S/MIMENetwork Working GroupD.Pinkas (Bull SAS) INTERNET-DRAFT N.Pope (Thales eSecurity) Expires May 2008 J.Ross (Security and Standards)D. Pinkas Request for Comments: 5126 Bull SAS Obsoletes:RFC3126November 2007 Intended status:N. Pope Category: Informational Thales eSecurity J. Ross Security and Standards February 2008 CMS Advanced Electronic Signatures (CAdES)<draft-ietf-smime-cades-07.txt>Status ofthisThis Memo This memoBy submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents ofprovides information for the InternetEngineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time.community. Itis inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The listdoes not specify an Internet standard ofcurrent Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html. The listany kind. Distribution ofInternet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Copyright Notice Copyright (C) The IETF Trust (2007).this memo is unlimited. Abstract This document defines the format of an electronic signature that can remain valid over long periods. This includes evidence as to its validity even if the signer or verifying party later attempts to deny (i.e., repudiates) the validity of the signature. The format can be considered as an extension to RFC 3852[4]and RFC2634 [5],2634, where, when appropriate, additional signed and unsigned attributes have been defined. The contents of this Informational RFCamountsamount to a transposition of the ETSITSTraffic Sector (TS) 101 733 V.1.7.4 (CMS Advanced Electronic Signatures--- CAdES)[TS101733]and is technically equivalent to it.The technical contents of this specification are maintained by ETSI. The ETSI TS and further updates are available free of charge at : http://www.etsi.org/WebSite/Standards/StandardsDownload.aspxTable of Contents 1. Introduction6....................................................6 2. Scope6...........................................................6 3. Definitions andabbreviations 8 3.1Abbreviations ...................................8 3.1. Definitions8 3.2................................................8 3.2. Abbreviations11.............................................11 4. Overview12 4.1.......................................................12 4.1. Majorparties 12 4.2 Signatures policies 14 4.3Parties .............................................13 4.2. Signature Policies ........................................14 4.3. Electronicsignature formats 14 4.3.1Signature Formats ..............................15 4.3.1. CAdES Basic Electronic Signature (CAdES-BES)14 4.3.2.......15 4.3.2. CAdES ExplicitPolicyPolicy-based Electronic Signatures (CAdES-EPES)17 4.4............................18 4.4. Electronicsignature formatsSignature Formats withvalidation data 18 4.4.1Validation Data .........19 4.4.1. Electronic Signature withTimeTime-stamp (CAdES-T)19 4.4.2.....20 4.4.2. ES with Completevalidation data referencesValidation Data References (CAdES-C)20 4.4.3..........................................21 4.4.3. Extendedelectronic signature formats 22 4.4.4Electronic Signature Formats ..............23 4.4.3.1. EXtended Long Electronic Signature (CAdES-X Long) ............................24 4.4.3.2. EXtended Electronic Signature with Time Type 1 ...............................25 4.4.3.3. EXtended Electronic Signature with Time Type 2 ...............................26 4.4.3.4. EXtended Long Electronic Signature with Time (CAdES-X Long ...................27 4.4.4. Archival Electronic Signature (CAdES-A)26 4.5............27 4.5. Arbitration27 4.6...............................................28 4.6. Validationprocess 28Process ........................................29 5. Electronicsignature attributes 29 5.1Signature Attributes ................................30 5.1. Generalsyntax 29 5.2Syntax ............................................30 5.2. Datacontent type 29 5.3Content Type .........................................30 5.3. Signed-datacontent type 29 5.4Content Type ..................................30 5.4. SignedDatatype 29 5.5Type ...........................................31 5.5. EncapsulatedContentInfotype 30 5.6Type ..............................31 5.6. SignerInfotype 30 5.6.1Type ...........................................31 5.6.1. Messagedigest calculation process 31 5.6.2Digest Calculation Process .................32 5.6.2. Messagesignature generation process 31 5.6.3Signature Generation Process ...............32 5.6.3. Messagesignature verification process 31 5.7Signature Verification Process .............32 5.7. Basic ESmandatory present attributes 31 5.7.1 Content type 31 5.7.2Mandatory Present Attributes .....................32 5.7.1. content-type .......................................32 5.7.2. Messagedigest 32 5.7.3Digest .....................................33 5.7.3. Signingcertificate reference attribute 32 5.8Certificate Reference Attributes ...........33 5.7.3.1. ESS signing-certificate Attribute Definition ................................34 5.7.3.2. ESS signing-certificate-v2 Attribute Definition ......................34 5.7.3.3. Other signing-certificate Attribute Definition ......................35 5.8. Additionalmandatory attributesMandatory Attributes for Explicit Policy-based Electronic Signatures34 5.8.1 Signature policy identifier 34 5.9........................36 5.8.1. signature-policy-identifier ........................36 5.9. CMSimported optional attributes 36 5.9.1 Signing time 36 5.9.2 Countersignature 36 5.10 ESS imported optional attributes 37 5.10.1 Content reference attribute 37 5.10.2 Content identifier attribute 37 5.10.3 Content hints attribute 37 5.11Imported Optional Attributes ..........................38 5.9.1. signing-time .......................................38 5.9.2. countersignature ...................................39 5.10. ESS-Imported Optional Attributes .........................39 5.10.1. content-reference Attribute .......................39 5.10.2. content-identifier Attribute ......................39 5.10.3. content-hints Attribute ...........................40 5.11. Additionaloptional attributes definedOptional Attributes Defined in thepresent document 38 5.11.1 Commitment type indication attribute 38 5.11.2 Signer location attribute 40 5.11.3 Signer attributes attribute 40 5.11.4 Content time-stamp 41 5.12Present Document .........................................40 5.11.1. commitment-type-indication Attribute ..............41 5.11.2. signer-location Attribute .........................43 5.11.3. signer-attributes Attribute .......................43 5.11.4. content-time-stamp ................................44 5.12. Support formultiple signatures 41 5.12.1Multiple Signatures ..........................44 5.12.1. Independentsignatures 41 5.12.2Signatures ............................44 5.12.2. Embeddedsignatures 42Signatures ...............................45 6. Additional Electronic Signaturevalidation attributes 42 6.1 Electronic Signature Time-stampedValidation Attributes ..........45 6.1. signature time-stamp Attribute (CAdES-T)43 6.1.1 Signature time- stamp attribute definition 44 6.2 Complete validation reference data (CAdES-C) 44 6.2.1 Complete certificate references attribute definition 45 6.2.2..................47 6.1.1. signature-time-stamp Attribute Definition ..........47 6.2. CompleteRevocationValidation Data Referencesattribute definition 45 6.2.3(CAdES-C) .............48 6.2.1. complete-certificate-references Attributecertificate references attribute definition 47 6.2.4Definition .........................................48 6.2.2. complete-revocation-references Attributerevocation references attribute definition 48 6.3Definition .........................................49 6.2.3. attribute-certificate-references Attribute Definition .........................................51 6.2.4. attribute-revocation-references Attribute Definition .........................................52 6.3. Extendedvalidation dataValidation Data (CAdES-X)48 6.3.1 Time-stamped validation data........................52 6.3.1. Time-Stamped Validation Data (CAdES-X Type 1 or Type 2)48 6.3.2.......................................53 6.3.2. Longvalidation dataValidation Data (CAdES-X Long, CAdES-X Long Type 1 or 2)48 6.3.3 Certificate values attribute definition 49 6.3.4 Revocation values attribute definition 50 6.3.5 CAdES-C time-stamp attribute definition 51 6.3.6 Time-stamped certificates and crls references attribute definition 52 6.4 Archive validation data 53 6.4.1..................................53 6.3.3. certificate-values Attribute Definition ............54 6.3.4. revocation-values Attribute Definition .............54 6.3.5. CAdES-C-time-stamp Attribute Definition ............56 6.3.6. time-stamped-certs-crls-references Attribute Definition ...............................57 6.4. Archivetime-stamp attribute definition 53Validation Data ...................................58 6.4.1. archive-time-stamp Attribute Definition ............58 7. Otherstandard data structures 55 7.1 Public-key certificate format 55 7.2Standard Data Structures .................................60 7.1. Public Key Certificaterevocation list format 55 7.3Format .............................60 7.2. Certificate Revocation List Format ........................60 7.3. OCSPresponse format 55 7.4 Time-stamp token format 55 7.5Response Format ......................................60 7.4. Time-Stamp Token Format ...................................60 7.5. Name andattribute formats 55 7.6Attributecertificate 56Formats ................................60 7.6. AttributeCertificate ......................................61 8. Conformancerequirements 56 8.1Requirements .......................................61 8.1. CAdES-Basic Electronic Signature (CAdES-BES)56 8.2..............62 8.2. CAdES-Explicit Policy-based Electronic Signature57 8.3..........63 8.3. Verificationusing time-stamping 57 8.4Using Time-Stamping ..........................63 8.4. Verificationusing secure records 58Using Secure Records .........................63 9.IANA Considerations 58 10.References58 10.1.....................................................64 9.1. Normativereferences 58 10.2References ......................................64 9.2. Informativereferences 59 11. Authors' addresses 62 12. Acknowledgments 62References ....................................65 Annex A (normative): ASN.1definitions 63 A.1Definitions ............................69 A.1. Signatureformat definitions usingFormat Definitions Using X.208 ASN.1syntax 63 A.2Syntax ...................................69 A.2. Signatureformat definitions usingFormat Definitions Using X.680 ASN.1syntax 71Syntax ...................................77 Annex B (informative): ExtendedformsForms of Electronic Signatures80 B.1....86 B.1. ExtendedformsForms ofvalidation data 80 B.1.1Validation Data ....................86 B.1.1. CAdES-X Long81 B.1.2..................................87 B.1.2. CAdES-X Type 182 B.1.3................................88 B.1.3. CAdES-X Type 283 B.1.4................................90 B.1.4. CAdES-X Long Type 1 and CAdES-X Long Type 285 B.2 Timestamp extensions 86 B.3...91 B.2. Time-Stamp Extensions ................................93 B.3. Archivevalidation dataValidation Data (CAdES-A)87 B.4....................94 B.4. Examplevalidation sequence 89 B.5Validation Sequence ..........................97 B.5. Additionaloptional features 94Optional Features ........................102 Annex C(informative):General description 95 C.1(informative): General Description .......................103 C.1. Thesignature policy 95 C.2Signature Policy ................................103 C.2. Signedinformation 96 C.3Information ..................................104 C.3. Components of anelectronic signature 96 C.3.1Electronic Signature ...............104 C.3.1. Reference to thesignature policy 96 C.3.2Signature Policy ............104 C.3.2. Commitmenttype indication 97 C.3.3Type Indication ...................105 C.3.3. CertificateidentifierIdentifier from thesigner 97 C.3.4Signer .......106 C.3.4. Roleattributes 98 C.3.4.1Attributes ..............................106 C.3.4.1. Claimedrole 98 C.3.4.2Role .......................107 C.3.4.2. Certifiedrole 99 C.3.5Role .....................107 C.3.5. Signerlocation 99 C.3.6Location ..............................108 C.3.6. Signingtime 99 C.3.7 Content format 100 C.3.8Time .................................108 C.3.7. Contenthints 100 C.3.9Format ...............................108 C.3.8. content-hints ................................109 C.3.9. Contentcross referencing 100 C.4Cross-Referencing ....................109 C.4. Components ofvalidation data 100 C.4.1Validation Data .......................109 C.4.1. Revocationstatus information 100 C.4.1.1Status Information ................109 C.4.1.1. CRLinformation 101 C.4.1.2Information .....................110 C.4.1.2. OCSPinformation 101 C.4.2Information ....................110 C.4.2. Certificationpath 102 C.4.3Path ...........................111 C.4.3. Time-stamping forlong lifeLong Life ofsignatures 102 C.4.4Signatures ....111 C.4.4. Time-stamping forlong lifeLong Life ofsignatureSignature before CA keycompromises 103 C.4.4.1Compromises ....................113 C.4.4.1. Time-stamping the ES withcomplete validation data 104 C.4.4.2 Time-stamping certificatesComplete Validation Data ...........113 C.4.4.2. Time-Stamping Certificates andrevocation information references 105 C.4.5Revocation Information References ..114 C.4.5. Time-stamping forarchiveArchive ofsignature 106 C.4.6Signature .......115 C.4.6. Reference toadditional data 107 C.4.7 Time-stampingAdditional Data .................116 C.4.7. Time-Stamping formutual recognition 107 C.4.8Mutual Recognition .........116 C.4.8. TSAkey compromise 108 C.5Key Compromise ...........................117 C.5. Multiplesignatures 108Signatures .................................118 Annex D(informative):Data protocols(informative): Data Protocols tointeroperateInteroperate with TSPs109 D.1..118 D.1. Operationalprotocols 109 D.1.1Protocols ...............................118 D.1.1. Certificateretrieval 109 D.1.2Retrieval ........................118 D.1.2. CRLretrieval 109 D.1.3 OnLine certificate status 109 D.1.4 Time-stamping 109 D.2Retrieval ................................118 D.1.3. Online Certificate Status ....................119 D.1.4. Time-Stamping ................................119 D.2. Managementprotocols 109 D.2.1Protocols ................................119 D.2.1. Request forcertificate revocation 109Certificate Revocation ...........119 Annex E (informative): Security Considerations110 E.1...................119 E.1. Protection ofprivate key 110 E.2Private Key ...........................119 E.2. Choice ofalgorithms 110Algorithms ................................119 Annex F (informative): Examplestructured contentsStructured Contents and MIME111 F.1......120 F.1. Generaldescription 111 F.2Description .................................120 F.1.1. Headerinformation 111 F.3Information ...........................120 F.1.2. Contentencoding 113 F.4 Multi-part content 113 F.5Encoding .............................121 F.1.3. Multi-Part Content ...........................121 F.2. S/MIME113..............................................122 F.2.1. Using application/pkcs7-mime .................123 F.2.2. Using application/pkcs7-signature ............124 Annex G (informative): Relationship to the European Directive and EESSI115 G.1.................................125 G.1. Introduction116 G.2........................................125 G.2. ElectronicsignaturesSignatures and thedirective 116 G.3Directive .............126 G.3. ETSIelectronic signature formatsElectronic Signature Formats and thedirective 117 G.4Directive .127 G.4. EESSIstandardsStandards andclassesClasses ofelectronic signature 117 G.4.1Electronic Signature .127 G.4.1. Structure of EESSIstandardization 117 G.4.2Standardization ...........127 G.4.2. Classes ofelectronic signatures 118 G.4.3Electronic Signatures .............128 G.4.3. EESSIclassesClasses and the ETSIelectronic signature format 118Electronic Signature Format .............................128 Annex H (informative): APIs for thegenerationGeneration andverificationVerification ofelectronic signatures tokens 118 H.1Electronic Signatures Tokens ...........129 H.1. Dataframing 119 H.2Framing ........................................129 H.2. IDUP-GSS-APIsdefinedDefined by the IETF120 H.3...................131 H.3. CORBAsecurity interfaces definedSecurity Interfaces Defined by the OMG121........132 Annex I(informative):Cryptographic algorithms 123 I.1(informative): Cryptographic Algorithms ..................133 I.1. Digestalgorithms 123 I.1.1Algorithms ...................................133 I.1.1. SHA-1123 I.1.2........................................133 I.1.2. General123 I.2......................................133 I.2. Digitalsignature algorithms 124 I.2.1Signature Algorithms ........................134 I.2.1. DSA124 I.2.2..........................................134 I.2.2. RSA124 I.2.3..........................................135 I.2.3. General125......................................135 Annex J (informative): Guidance onnaming 127 J.1Naming ........................137 J.1. Allocation ofnames 127 J.2Names .................................137 J.2. ProvidingaccessAccess toregistration information 127 J.3Registration Information ........138 J.3. Namingschemes 128 J.3.1Schemes ......................................138 J.3.1. NamingschemesSchemes forindividual citizens 128 J.3.2Individual Citizens .......138 J.3.2. NamingschemesSchemes foremployeesEmployees of anorganization 128 Annex K (informative): Changes from the previous version 130 Full Copyright Statement 131 Intellectual Property 131 Acknowledgements 132Organization .................................139 1. Introduction This document is intended to cover electronic signatures for various types of transactions, including business transactions(e.g.(e.g., purchase requisition, contract, and invoice applications) wherelong termlong-term validity of such signatures is important. This includes evidence as to its validity even if the signer or verifying party later attempts to deny (i.e.,repudiates,repudiates; see ISO/IEC 10181-5 [ISO10181-5]) the validity of thesignature). Thussignature. Thus, the present document can be used for any transaction between an individual and a company, between two companies, between an individual and a governmental body, etc. The present document is independent of anyenvironment. Itenvironment; it can be applied to anyenvironment e.g.environment, e.g., smart cards,GSM SIMGlobal System for Mobile Communication Subscriber Identity Module (GSM SIM) cards, special programs for electronic signatures, etc. The European Directive on a community framework for Electronic Signatures defines an electronic signature as: "Data in electronic form which is attached to or logically associated with other electronic data and which serves as a method of authentication". An electronicsignaturesignature, as used in the presentdocumentdocument, is a form of advanced electronicsignaturesignature, as defined in the Directive. 2. Scope The scope of the present document coversElectronic Signature Formatselectronic signature formats only. The aspects of Electronic Signature Policies are defined in RFC 3125 [RFC3125] andinETSI TR 102 272 [TR102272]. The present document defines a number ofElectronic Signature Formats, includingelectronic signature formats, including electronic signatures that can remain valid over long periods. This includes evidence as to its validity even if the signer or verifying party later attempts to deny (repudiates) the validity of the electronic signature. The present document specifies use oftrusted service providers (e.g.Trusted Service Providers (e.g., Time-StampingAuthorities),Authorities) and the data that needs to be archived(e.g. cross certificates(e.g., cross-certificates and revocation lists) to meet the requirements oflong termlong-term electronic signatures. An electronicsignaturesignature, as defined by the presentdocumentdocument, can be used for arbitration in case of a dispute between the signer and verifier, which may occur at some later time, even years later. The present document includes the concept of signature policies that can be used to establish technical consistency when validating electronicsignaturessignatures, but it does not mandate their use. The present document is based on the use of public key cryptography to produce digital signatures, supported by public key certificates. The present document also specifies the use of time-stamping andtime- markingtime-marking services to prove the validity of a signature long after the normal lifetime of critical elements of an electronic signature.ItThis document also, as an option, defines ways to provide very long-term protection against key compromise or weakened algorithms. The present document builds on existing standards that are widely adopted.This includes:These include: - RFC 3852[4][4]: "Cryptographic Message Syntax (CMS)"; - ISO/IEC 9594-8/ITU-T Recommendation X.509 [1]: "Information technology - Open Systems Interconnection - The Directory: Authentication framework"; - RFC 3280[2][2]: "Internet X.509 Public Key Infrastructure (PKIX) Certificate andCRLCertificate Revocation List (CRL) Profile"; - RFC 3161[7][7]: "Internet X.509 Public Key Infrastructure Time-StampProtocol".Protocol (TSP)". NOTE: SeesectionSection 11 for a full set of references. The present document describes formats for advanced electronic signatures using ASN.1 (Abstract Syntax Notation 1) [14]. ASN.1 is encoded using X.690 [16]. These formats are based on CMS (Cryptographic Message Syntax) defined in RFC 3852 [4]. These electronic signatures are thus called CAdES, for "CMS Advanced Electronic Signatures". Another document, TS 101 903 [TS101903], describes formats for XML advanced electronic signatures (XAdES) built on XMLDSIG [XMLDSIG]. In addition, the present document identifies other documents that define formats for Public Key Certificates, Attribute Certificates, and Certificate Revocation Lists and supporting protocols,including,including protocols for useofby trusted third parties to support the operation of electronic signature creation and validation. Informative annexes include: - illustrations of extended forms ofextendedElectronicSignaturesSignature formats that protect against various vulnerabilities and examples of validation processes (Annex B); - descriptions and explanations of some of the concepts used in the present document, giving a rationale for normative parts of the present document (Annex C); - information on protocols to interoperate with Trusted Service Providers (Annex D); - guidance on naming (Annex E); - an example structured content and MIME (Annex F); - the relationship between the present document and the directive on electronic signature and associated standardization initiatives (Annex G); - APIs to support the generation andtheverification of electronic signatures (Annex H); - cryptographic algorithms that may be used (Annex I); and -changes from the previous versionnaming schemes (see Annex J).33. Definitions andabbreviations 3.1Abbreviations 3.1. Definitions For the purposes of the present document, the following terms and definitions apply: Arbitrator: an arbitrator entity may be used to arbitrate a dispute between a signer and verifier when there is a disagreement on the validity of a digital signature. Attribute Authority (AA): an authoritywhichthat assigns privileges by issuing attribute certificates. Authoritycertificate:Certificate: a certificate issued to an authority(e.g.(e.g., either to a certification authority ortoan attribute authority). Attribute Authority Revocation List (AARL): a revocation list containing a list of references to certificates issued toAAs,AAs that are no longer considered valid by the issuing authority. Attribute Certificate Revocation List (ACRL): a revocation list containing a list of references to attribute certificates that are no longer considered valid by the issuing authority. Certification Authority Revocation List (CARL): a revocation list containing a list ofpublic-keypublic key certificates issued to certificationauthorities,authorities that are no longer considered valid by the certificate issuer. Certification Authority (CA): an authority trusted by one or more users to create and assign public keycertificates, optionallycertificates; optionally, the certification authority may create the users' keys. NOTE: See ITU-T Recommendation X.509 [1]. Certificate Revocation List (CRL): a signed list indicating a set of public key certificates that are no longer considered valid by the certificate issuer. Digitalsignature:Signature: data appended to, or a cryptographic transformation of, a data unit that allows a recipient of the data unit to prove the source and integrity of the data unit and protect against forgery,e.g.e.g., by the recipient. NOTE: See ISO 7498-2 [ISO7498-2]. Electronicsignature:Signature: data in electronic formwhich arethat is attached to or logically associated with other electronic data andwhich servethat serves as a method of authentication. NOTE: See Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on a Community framework for electronic signatures[EU Directive].[EUDirective]. Enhancedelectronic signatures:Electronic Signatures: electronic signatures enhanced by complementing the baseline requirements with additional data, such astime tamptime-stamp tokens and certificate revocation data, to address commonly recognized threats. Explicit Policy-based Electronic Signature (EPES): an electronic signature where the signature policy is explicitly specified that shall be used to validate it. Graceperiod:Period: a time periodwhichthat permits the certificate revocation information to propagate through the revocation process to relying parties. Initialverification:Verification: a process performed by a verifier done after an electronic signature is generated in order to capture additional information that could make it valid forlong termlong-term verification. Public Key Certificate (PKC): public keys of a user, together with some other information, rendered unforgeable by encipherment with the private key of the certification authoritywhichthat issued it. NOTE: See ITU-T Recommendation X.509 [1]. Rivest-Shamir-Adleman (RSA): an asymmetric cryptography algorithm based on the difficulty to factor very largenumbers,numbers using a key pair: a private key and a public key. Signaturepolicy:Policy: a set of rules for the creation and validation of an electronicsignature,signature that defines the technical and procedural requirements for electronic signature creation and validation, in order to meet a particular business need, and under which the signature can be determined to be valid. Signaturepolicy issuer:Policy Issuer: an entity that defines and issues a signature policy. Signaturevalidation policy:Validation Policy: part of the signature policywhichthat specifies the technical requirements on the signer in creating a signature and verifier when validating a signature. Signer: an entity that creates an electronic signature. Subsequent Verification: a process performed by a verifier to assess the signature validity. NOTE:ItSubsequent verification may be done even years after the electronic signature was produced by the signer and completed by theInitial Verificationinitial verification, and it might not need to capture more data than those captured at the time of initial verification. Time-Stamptoken:Token: a data object that binds a representation of a datum to a particular time, thus establishing evidence that the datum existed before that time. Time-Mark: information in an audit trail from a Trusted Service Provider that binds a representation of a datum to a particular time, thus establishing evidence that the datum existed before that time. Time-Marking Authority: a trusted third party that creates records in an audit trail in order to indicate that a datum existed before a particular point in time. Time-Stamping Authority (TSA): a trusted third party that createstime- stamptime-stamp tokens in order to indicate that a datum existed at a particular point in time. Time-Stamping Unit (TSU): a set of hardware and softwarewhichthat is managed as a unit and has a single time-stamp token signing key active at a time. Trusted Service Provider (TSP): an entity that helps to build trust relationships by making available or providing some information upon request. Validationdata:Data: additional data that may be used by a verifier of electronic signatures to determine that the signature is valid. Validelectronic signature:Electronic Signature: an electronic signaturewhichthat passes validation. Verifier: an entity that verifies evidence. NOTE 1: See ISO/IEC 13888-1 [ISO13888-1]. NOTE 2: Within the context of the presentdocumentdocument, this is an entity that validates an electronic signature.3.23.2. Abbreviations For the purposes of the present document, the following abbreviations apply: AA Attribute Authority AARL Attribute Authority Revocation List ACRL Attribute Certificate Revocation List API Application Program Interface ASCII American Standard Code for Information Interchange ASN.1 Abstract Syntax Notation 1 CA Certification Authority CAD Card Accepting Device CAdES CMS Advanced Electronic Signature CAdES-A CAdES with Archive validation data CAdES-BES CAdES Basic Electronic Signature CAdES-C CAdES with Complete validation data CAdES-EPES CAdES Explicit Policy Electronic Signature CAdES-T CAdES with Time-stamp CAdES-X CAdES with eXtended validation data CAdES-X Long CAdES with EXtended Long validation data CARL Certification Authority Revocation List CMS Cryptographic Message Syntax CRL Certificate Revocation List CWA CEN (European Committee for Standardization) Workshop Agreement DER Distinguished Encoding Rules (for ASN.1) DSA Digital Signature Algorithm EDIFACT Electronic Data Interchange For Administration, Commerce and Transport EESSI European Electronic Signature Standardization Initiative EPES Explicit Policy-based Electronic Signature ES Electronic Signature ESS Enhanced Security Services (enhances CMS) IDL Interface Definition Language MIME Multipurpose Internet Mail Extensions OCSP Online Certificate Status Provider OID Object IDentifier PKC Public Key Certificate PKIX Public Key Infrastructure using X.509 (IETF Working Group) RSA Rivest-Shamir-Adleman SHA-1 Secure Hash Algorithm 1 TSA Time-Stamping Authority TSP Trusted Service Provider TST Time-Stamp Token TSU Time-Stamping Unit URI Uniform Resource Identifier URL Uniform Resource Locator XMLeXtended Mark upExtensible Markup Language XMLDSIG XML-Signature Syntax and Processing44. Overview The present document defines a number of Electronic Signature (ES) formats that build on CMS (RFC 3852 [4]) by adding signed and unsigned attributes. Thissectionsection: - provides an introduction to the major parties involved(section(Section 4.1), - provides the concept ofSignature Policies (sectionsignature policies (Section 4.2), - provides an overview of the various ES formats(section(Section 4.3), - introduces the concept of validationdatadata, and provides an overview of formats that incorporate validation data(section(Section 4.4), and - presents relevant considerations on arbitration(section(Section 4.5) and for the validation process(section(Section 4.6). The formal specifications of the attributes are specified insectionsSections 5 and6, annexes6; Annexes C and D provide rationale for the definitions of the different ES forms.4.14.1. MajorpartiesParties The major parties involved in a business transaction supported by electronicsignaturessignatures, as defined in the presentdocumentdocument, are: - theSigner;signer; - theVerifier;verifier; - Trusted Service Providers (TSP); and - theArbitrator.arbitrator. The signer is the entity that creates the electronic signature. When the signer digitally signs over data using the prescribed format, this represents a commitment on behalf of the signing entity to the data being signed. The verifier is the entity that validates the electronicsignature,signature; it may be a single entity or multiple entities. The Trusted Service Providers (TSPs) are one or more entities that help to build trust relationships between the signer and verifier. They support the signer and verifier by means of supporting services including: user certificates, cross-certificates, time-stamp tokens, CRLs, ARLs, and OCSP responses. The following TSPs are used to support the functions defined in the present document: - Certification Authorities; - Registration Authorities; - CRL Issuers; - OCSP Responders; - Repository Authorities(e.g.(e.g., a Directory); - Time-Stamping Authorities; - Time-Marking Authorities; and - Signature Policy Issuers. Certification Authorities provide users with public key certificates andwitha revocation service. Registration Authorities allow the identification and registration of entities before a CA generates certificates. Repository Authorities publish CRLs issued by CAs, signature policies issued by Signature PolicyIssuersIssuers, and optionally public key certificates. Time-Stamping Authorities attest that some data was formed before a given trusted time. Time-Marking Authorities record that some data was formed before a given trusted time. Signature Policy Issuers define the signature policies to be used by signers and verifiers. In somecasescases, the following additional TSPs are needed: - Attribute Authorities. Attributes Authorities provide users with attributes linked to public key certificates. An Arbitrator is an entity that arbitrates in disputes between a signer and a verifier.4.2 Signatures policies4.2. Signature Policies The present document includes the concept of signature policies that can be used to establish technical consistency when validating electronic signatures. When a comprehensive signature policy used by the verifier is either explicitly indicated by the signer or implied by the data being signed, then a consistent result can be obtained when validating an electronic signature. When the signature policy being used by the verifier is neither indicated by the signer nor can be derived from other data, or the signature policy isincompleteincomplete, then verifiers, including arbitrators, may obtain different results when validating an electronic signature. Therefore, comprehensive signature policies that ensure consistency of signature validation are recommended from both thesignerssigner's andverifiersverifier's point of view. Further information on signature policies is provided in: - TR 102 038 [TR102038]; -sectionsSections 5.8.1,C.1C.1, and C.3.1 of the present document; - RFC 3125 [RFC3125]; and - TR 102 272 [TR102272].4.34.3. Electronicsignature formatsSignature Formats The currentdocument sectionprovidessection provides an overview for two forms of CMS advanced electronic signature specified in the present document, namely, the CAdES Basic Electronic Signature (CAdES-BES) and the CAdES Explicit Policy-based Electronic Signature (CAdES-EPES). Conformance to the present document mandates that the signercreatescreate one of these formats.4.3.14.3.1. CAdES Basic Electronic Signature (CAdES-BES) A CAdES Basic Electronic Signature(CAdES-BES)(CAdES-BES), in accordance with the present document, contains: - The signed user data(e.g.(e.g., the signer'sdocument)document), as defined in CMS (RFC 3852 [4]); - A collection of mandatory signedattributesattributes, as defined in CMS (RFC 3852 [4]) and in ESS (RFC 2634 [5]); - Additional mandatory signedattributesattributes, defined in the present document; and - The digital signature value computed on the user data and, when present, on the signed attributes, as defined in CMS (RFC 3852 [4]). A CAdES Basic Electronic Signature(CAdES-BES)(CAdES-BES), in accordance with the presentdocumentdocument, may contain: - a collection of additional signed attributes; and - a collection of optional unsigned attributes. The mandatory signed attributes are: - Content-type. It is defined in RFC 3852 [4] and specifies the type of the EncapsulatedContentInfo value being signed. Details are provided in5.7.1.Section 5.7.1 of the present document. Rationale for its inclusion is provided insectionAnnex C.3.7; - Message-digest. It is defined in RFC 3852 [4] and specifies the message digest of the eContent OCTET STRING within encapContentInfo being signed. Details are provided insectionSection 5.7.2; - ESS signing-certificate OR ESSsigning-certificate v2.signing-certificate-v2. The ESS signing-certificate attribute is defined in Enhanced Security Services (ESS), RFC 2634[5][5], and only allows for the use of SHA-1 as a digest algorithm. The ESSsigning-certificatesigning-certificate-v2 attributeV2is defined in "ESS Update: Adding CertID AlgorithmAgility"Agility", RFC 5035 [15], and allows for the use of any digest algorithm. A CAdES-BES claiming compliance with the present document must include one of them. Section 5.7.3 provides the details of these attributes. Rationale for its inclusion is provided insectionAnnex C.3.3. Optional signed attributes may be added to the CAdES-BES, including optional signed attributes defined in CMS (RFC 3852 [4]), ESS (RFC 2634[5])[5]), and the present document. Listed below are optional attributes that are defined insectionSection 5 and have arationalrationale provided inannexAnnex C: - Signing-time: as defined in CMS (RFC 3852[4])[4]), indicates the time of thesignaturesignature, as claimed by the signer. Details and short rationale are provided insection 5.9.1.Section 5.9.1. Annex C.3.6 provides the rationale. -Content-hintscontent-hints: as defined in ESS (RFC 2634[5])[5]), provides information that describes the innermost signed content of a multi-layer message where one content is encapsulated in another. Section 5.10.1 provides the specification details.SectionAnnex C.3.8 provides the rationale. -Content-reference.content-reference: as defined in ESS (RFC 2634[5])[5]), can be incorporated as a way to link request and reply messages in an exchange between two parties. Section 5.10.1 provides the specification details.SectionAnnex C.3.9 provides the rationale. -Content-identifier.content-identifier: as defined in ESS (RFC 2634[5])[5]), contains an identifier that may be used later on in the previouscontent- referencecontent-reference attribute. Section 5.10.2 provides the specification details.Section C.3.8 provides the rationale.-Commitment-type-indication. Thiscommitment-type-indication: this attribute is defined by the present document as a way to indicate the commitment endorsed by the signer when producing the signature. Section 5.11.1 provides the specification details.SectionAnnex C.3.2 provides the rationale. -Signer-location. Thissigner-location: this attribute is defined by the present document. It allows the signer to indicate the place where the signer purportedly produced the signature. Section 5.11.2 provides the specification details.SectionAnnex C.3.5 provides the rationale. -Signer-attributes. Thissigner-attributes: this attribute is defined by the present document. It allows a claimed or certified role to be incorporated into the signed information. Section 5.11.3 provides the specification details.SectionAnnex C.3.4 provides the rationale. -Content-time-stamp. Thiscontent-time-stamp: this attribute is defined by the present document. It allows a time-stamp token of the data to be signed to be incorporated into the signed information. It provides proof of the existence of the data before the signature was created. Section 5.11.4 provides the specification details.SectionAnnex C.3.6 provides the rationale. A CAdES-BES form can also incorporate instances of unsignedattributesattributes, as defined in CMS (RFC 3852 [4]) and ESS (RFC 2634 [5]). - CounterSignature, as defined in CMS (RFC 3852[4]). It[4]); it can be incorporated wherever embedded signatures(i.e.(i.e., a signature on a previous signature) are needed. Section 5.9.2 provides the specification details.SectionAnnex C.5 inannexAnnex C provides the rationale. The structure of the CAdES-BES is illustrated infigureFigure 1. +------Elect.Signature (CAdES-BES)------+ |+----------------------------------- + | ||+---------+ +----------+ | | |||Signer's | | Signed | Digital | | |||Document | |Attributes| Signature | | ||| | | | | | ||+---------+ +----------+ | | |+------------------------------------+ | +---------------------------------------+ Figure 1: Illustration of a CAdES-BES The signer's conformance requirements of a CAdES-BES are defined insectionSection 8.1. NOTE: The CAdES-BES is the minimum format for an electronic signature to be generated by the signer. On its own, it does not provide enough information for it to be verified in the longer term. For example, revocation information issued by the relevant certificate status information issuer needs to be available forlong termlong-term validation (seesectionSection 4.4.2). The CAdES-BES satisfies the legal requirements for electronicsignaturessignatures, as defined in the European Directive onelectronic signatures,Electronic Signatures, (seeannexAnnex C for further discussion on the relationship of the present document to the Directive). It provides basic authentication and integrity protection. The semantics of the signed data of a CAdES-BES or its context may implicitly indicate a signature policy to the verifier. Specification of the contents of signature policies is outside the scope of the present document. However, further information on signature policies is provided in TR 102 038 [TR102038], RFC 3125[RFC3125][RFC3125], andsectionsSections 5.8.1,C.1C.1, and C.3.1 of the present document.4.3.24.3.2. CAdES ExplicitPolicyPolicy-based Electronic Signatures (CAdES-EPES) A CAdES Explicit Policy-based Electronic Signature(CAdES-EPES)(CAdES-EPES), in accordance with the present document, extends the definition of an electronic signature to conform to the identified signature policy. A CAdES Explicit Policy-based Electronic Signature (CAdES-EPES) incorporates a signed attribute(signature-policy-identifier)(sigPolicyID attribute) indicatingthat a signature policy that is mandatory to use to validate the signature and specifies explicitlythe signature policy that shall beused.used to validate the electronic signature. This signed attribute is protected by the signature. The signature may also have other signed attributes required to conform to the mandated signature policy. Section 5.7.3 provides the details on the specification ofsignature- policy-identifiersignature-policy-identifier attribute.SectionAnnex C.1 provides a short rationale. Specification of the contents of signature policies is outside the scope of the present document. Further information on signature policies is provided in TR 102 038 [TR102038] andsectionsSections 5.8.1,C.1C.1, and C.3.1 of the present document. The structure of the CAdES-EPES is illustrated infigureFigure 2. +------------- Elect.Signature (CAdES-EPES) ---------------+ | | |+-------------------------------------------------------+ | || +-----------+ | | || | | +---------------------------+ | | || | | | +----------+ | | | || | Signer's | | |Signature | Signed | Digital | | || | Document | | |Policy ID | Attributes |Signature| | || | | | +----------+ | | | || | | +---------------------------+ | | || +-----------+ | | |+-------------------------------------------------------+ | | | +----------------------------------------------------------+ Figure 2: Illustration of a CAdES-EPES The signer's conformance requirements of CAdES-EPES are defined insectionSection 8.2.4.44.4. Electronicsignature formatsSignature Formats withvalidation dataValidation Data Validation of an electronicsignaturesignature, in accordance with the presentdocumentdocument, requires additional data needed to validate the electronic signature. This additional data is called validationdata;data, and includes: - Public Key Certificates (PKCs); - revocation status information for each PKC; - trusted time-stamps applied to the digitalsignature orsignature, otherwise atime- marktime-mark shall be available in an auditlog; andlog. - when appropriate, the details of a signature policy to be used to verify the electronic signature. The validation data may be collected by the signer and/or the verifier. When the signature-policy-identifier signed attribute is present, it shall meet the requirements of the signature policy. Validation data includes CA certificates as well as revocation status information in the form of Certificate Revocation Lists (CRLs) or certificate status information (OCSP) provided by anon-lineonline service. Validation data also includes evidence that the signature was created before a particular point intimetime; this may be either a time-stamp token or time-mark. The present document defines unsigned attributes able to contain validation data that can be added to CAdES-BES andCAdES-EPESCAdES-EPES, leading to electronic signature formats that include validation data.SectionsThe sections below summarize these formats and their most relevant characteristics.4.4.14.4.1. Electronic Signature withTimeTime-stamp (CAdES-T)Electronic SignatureAn electronic signature withTime (CAdES-T)time (CAdES-T), in accordance with the presentdocumentdocument, is when there exits trusted time associated with the ES. The trusted time may be provided by: -the signature-time-stampa time-stamp attribute as an unsigned attribute added to the ES; and -A time marka time-mark of the ES provided by atrusted service provider.Trusted Service Provider. Thesignature-time-stamptime-stamp attribute contains a time-stamp token of the electronic signature value. Section 6.1.1 provides the specification details.SectionAnnex C.4.3inprovides the rationale. A time-mark provided by a Trusted Service would have a similar effect to the signature-time-stampattributeattribute, but in thiscasecase, no attribute is added to theESES, as it is the responsibility of the TSP to provide evidence of atime marktime-mark when required to do so. The management of time marks is outside the scope of the present document. Trusted time provides the initial steps towards providinglong termlong-term validity. Electronic signatures with thetime stamptime-stamp attribute forming the CAdES-Tisare illustrated infigureFigure 3. +-------------------------------------------------CAdES-T ---------+ |+------ CAdES-BES or CAdES-EPES -------+ | ||+-----------------------------------+ | +----------------------+ | |||+---------+ +----------+ | | | | | ||||Signer's | | Signed | Digital | | | Signature-time-stamp | | ||||Document | |Attributes| Signature | | | attribute required | | |||| | | | | | | when using time | | |||+---------+ +----------+ | | | stamps. | | ||+-----------------------------------+ | | | | |+--------------------------------------+ | or the BES/EPES | | | | shall betime markedtime-marked | | | | | | | | Management and | | | | provision of time | | | | mark is the | | | | responsibility of | | | | the TSP. | | | +----------------------+ | +------------------------------------------------------------------+ Figure 3: Illustration of CAdES-T formats NOTE1 :1: Atime stamptime-stamp token is added to the CAdES-BES or CAdES-EPES as an unsigned attribute. NOTE2 : Timestamp2: Time-stamp tokens that may themselves include unsigned attributes required to validate thetimestamptime-stamp token, such as the complete-certificate-references andcomplete- revocation-references attributescomplete-revocation-references attributes, as defined by the present document.4.4.24.4.2. ES with Completevalidation data referencesValidation Data References (CAdES-C) Electronic Signature with Complete validation data references(CAdES-C)(CAdES-C), in accordance with the presentdocumentdocument, adds to the CAdES-T the complete-certificate-references and complete-revocation-referencesattributesattributes, as defined by the present document. Thecomplete- certificate-referencescomplete-certificate-references attributecontaincontains references to all the certificates present in the certification path used for verifying the signature. The complete-revocation-references attribute contains references to the CRLs and/or OCSP responses used for verifying the signature. Section 6.2 provides the specification details. Storing the references allows the values of the certification path and theCRLsCRL's orOCSPsOCSP's responses to be stored elsewhere, reducing the size of a stored electronic signature format. Sections C.4.1 to C.4.2 provide rationale on the usage of validation data and when it is suitable to generate the CAdES-C form. Electronicsignaturessignatures, with the additional validation data forming theCAdES-CCAdES-C, are illustrated infigureFigure 4. +------------------------- CAdES-C --------------------------------+ |+----------------------------- CAdES-T ---------+ | || +----------+ | +-------------+ | || |Timestamp | | | | | || |attribute | | | | | ||+- CAdES-BES or CAdES-EPES ------+|over | | | | | ||| ||digital | | | Complete | | |||+---------++----------+ ||signature | | | certificate | | ||||Signer's || Signed | Digital ||is | | | and | | ||||Document ||Attributes|Signature||mandatory | | | revocation | | |||| || | ||if is not | | | references | | |||+---------++----------+ ||timemarked| | | | | ||+--------------------------------++----------+ | | | | |+-----------------------------------------------+ +-------------+ | +------------------------------------------------------------------+ Figure 4: Illustration of CAdES-C format NOTE 1: The complete certificate and revocation references are added to the CAdES-T as an unsigned attribute. NOTE 2: As a minimum, the signer will provide the CAdES-BESoror, when indicating that the signature conforms to an explicit signingpolicypolicy, the CAdES-EPES. NOTE 3: To reduce the risk of repudiating signature creation, the trusted time indication needs to be as close as possible to the time the signature was created. The signer or a TSP could provide theCAdES-T,CAdES-T; ifnotnot, the verifier should create the CAdES-T on first receipt of an electronic signature because the CAdES-T provides independent evidence of the existence of the signature prior to the trusted time indication. NOTE 4:AnA CAdES-T trusted timeindicationsindication must be created before a certificate has been revoked or expired. NOTE 5: The signer and TSP could provide theCAdES-C,CAdES-C to minimize thisriskrisk, and when the signer does not provide the CAdES-C, the verifier should create the CAdES-C when the required component of revocation and validation data becomeavailable,available; this may require a grace period. NOTE 6: A grace period permits certificate revocation information to propagate through the revocation processes. This period could extend from the time an authorized entity requests certificaterevocation,revocation to when the information is available for the relying party to use. In order to make sure that the certificate was not revoked at the time the signature was time-marked or time-stamped, verifiers should wait until the end of the grace period. A signature policy may define specific values for grace periods. An illustration of a grace period is provided infigureFigure 5. +<--------------Grace Period --------->+ ----+-------+-------+--------+---------------------+----------+ ^ ^ ^ ^ ^ ^ | | | | | | | | | | | | Signature | First | Second | creation | revocation | revocation | time | status | status | | checking | checking | | | | Time-stamp Certification Build or path CAdES-C time-mark construction over & verification signature Figure 5: Illustration of a grace period NOTE 7: CWA 14171 [CWA14171] specifies a signature validation process using CAdES-T,CAdES-CCAdES-C, and a grace period. Annex B provides example validation processes.SectionAnnex C.4 provides additional information about applying grace periods during the validation process. The verifier's conformance requirements are defined insectionSection 8.3 fortime stamped CAdES-Ctime-stamped CAdES-C, andsectionSection 8.4 fortime markedtime-marked CAdES-C. The present document only defines conformance requirements for the verifier up to an ES withcompleteComplete validation data (CAdES-C). This means that none of the extended and archive forms ofElectronic Signatureelectronic signatures, as defined insectionsSections 4.4.3 to4.4.4)4.4.4, need to be implemented to achieve conformance to the present document.4.4.34.4.3. Extendedelectronic signature formatsElectronic Signature Formats CAdES-C can be extended by adding unsigned attributes to the electronic signature. The present document defines various unsigned attributes that are applicable for verylong termlong-term verification, and for preventing some disaster situationswhichthat are discussed inannexAnnex C. Annex B provides the details of the various extended formats, all the required unsigned attributes for eachtypetype, and how they can be used within the electronic signature validation process. The sections below give an overview of the various forms of extended signature formats in the present document.4.4.3.14.4.3.1. EXtended Long Electronic Signature (CAdES-X Long) Extended Long format (CAdES-XLong)Long), in accordance with the presentdocumentdocument, addsto the CAdES-C formatthe certificate-values and revocation-valuesattributes.attributes to the CAdES-C format. The first one contains the whole certificate path required for verifying the signature; the second one contains the CRLs and/OCSP responses required for the validation of the signature. This provides a known repository of certificate and revocation information required to validateana CAdES-C and prevents such information from getting lost. Sections 6.3.3 and 6.3.4 give specification details.SectionAnnex B.1.1 gives details on the production of the format.SectionsAnnexes C4.1 to C.4.2 provide the rationale. The structure of the CAdES-X Long format is illustrated infigureFigure 6. +----------------------- CAdES-X-Long -----------------------------+ |+------------------------------------ CadES-C --+ | || +----------+ | +-------------+ | ||+------ CAdES -------------------+|Timestamp | | | | | ||| || over | | | Complete | | |||+---------++----------+ ||digital | | | certificate | | ||||Signer's || Signed | Digital ||signature | | | and | | ||||Document ||Attributes|Signature|| | | | revocation | | |||| || | ||Optional | | | data | | |||+---------++----------+ ||when | | | | | ||+--------------------------------+|timemarked| | | | | || +----------+ | | | | || +-------------+ | +-------------+ | || | Complete | | | || | certificate | | | || | and | | | || | revocation | | | || | references | | | || +-------------+ | | |+-----------------------------------------------+ | | | +------------------------------------------------------------------+ Figure 6: Illustration of CAdES-X-Long4.4.3.24.4.3.2. EXtended Electronic Signature with Time Type 1 (CAdES-X Type 1) Extended format with time type 1 (CAdES-X Type1)1), in accordance with the presentdocumentdocument, addsto the CAdES-C formatthe CAdES-C-time-stamp attribute, whose content is a time-stamp token on the CAdES-Citself.itself, to the CAdES-C format. This provides an integrity and trusted time protection over all the elements and references. It may protect the certificates,CRLsCRLs, and OCSP responses in case of a later compromise of a CA key, CRLkeykey, or OCSP issuer key. Section 6.3.5 provides the specification details.SectionAnnex B.1.2 gives details on the production of the time-stamping process.SectionsAnnex C.4.4.1 provides the rationale. The structure of the CAdES-X Type 1 format is illustrated infigureFigure 7. +----------------------- CAdES-X-Type 1 ------------------------------+ |+-------------------------------------- CAdES-C -----+ | || +-------------+ | +-----------+ | ||+--------- CAdES ------------------+| Timestamp | | | | | ||| || over | | | | | |||+---------++----------+ || digital | | | | | ||||Signer's || Signed | Digital || signature | | | Timestamp | | ||||Document ||Attributes| Signature || | | | over | | |||| || | || Optional | | | CAdES-C | | |||+---------++----------+ || when | | | | | ||+----------------------------------+| time-marked | | | | | || +-------------+ | | | | || +-------------+ | +-----------+ | || | Complete | | | || | certificate | | | || | and | | | || | revocation | | | || | references | | | || +-------------+ | | |+----------------------------------------------------+ | +---------------------------------------------------------------------+ Figure 7: Illustration of CAdES-X Type 14.4.3.34.4.3.3. EXtended Electronic Signature with Time Type 2 (CAdES-X Type 2) Extended format with time type 2 (CAdES-X Type2)2), in accordance with the presentdocumentdocument, adds to the CAdES-C format theCAdES-C-time- stamped-certs-crls-referencesCAdES-C-time-stamped-certs-crls-references attribute, whose content is a time-stamp token on the certification path and revocation information references. This provides an integrity and trusted time protection over all the references. It may protect the certificates, CRLs and OCSP responses in case of a later compromise of a CA key, CRL key or OCSP issuer key. Both CAdES-X Type 1 and CAdES-X Type 2 counter the samethreatsthreats, and the usage of one or the other depends on the environment. Section 6.3.5 provides the specification details.SectionAnnex B.1.3 gives details on the production of the time-stamping process.SectionAnnex C.4.4.2 provides the rationale. The structure of the CAdES-X Type 2 format is illustrated infigureFigure 8. +------------------------- CAdES-X-Type 2 ----------------------------+ |+----------------------------------------CAdES-C ---+ | || +------------+| | ||+----- CAdES -----------------------+|TimmestampTimestamp || | ||| || over || | |||+---------+ +----------+ || digital || +-------------+| ||||Signer's | | Signed | Digital || signature || | Time-stamp || ||||Document | |Attributes| signature || || | only over || |||| | | | || optional || | complete || |||+---------+ +----------+ || when || | certificate || ||+-----------------------------------+| timemarked || | and || || +------------+| | revocation || || +-------------+ | | references || || | Complete | | +-------------+| || | certificate | | | || | and | | | || | revocation | | | || | references | | | || +-------------+ | | |+---------------------------------------------------+ | +---------------------------------------------------------------------+ Figure 8: Illustration of CAdES-X Type 24.4.3.44.4.3.4. EXtended Long Electronic Signature with Time (CAdES-X Long Type 1 or 2) Extended Long with Time (CAdES-X Long Type 1 or2)2), in accordance with the presentdocumentdocument, is a combination of CAdES-X Long and one of the two former types (CAdES-X Type 1 and CAdES-X Type 2).SectionAnnex B.1.4 gives details on the production of the time-stamping process.Section C4.8Annex C.4.8 inannexAnnex C provides the rationale. The structure of the CAdES-X Long Type 1 and CAdES-X Long Type2.2 format is illustrated infigureFigure 9. +------------------ CAdES-X Long Type 1 or 2 -----------------------+ | +--------------+| |+-------------------------------------- CAdES-C --+|+------------+|| || ||| Timestamp ||| ||+------- CAdES --------------------++----------+ ||| over ||| ||| ||Timestamp | ||| CAdES-C ||| ||| ||over | ||+------------+|| |||+---------++----------+ ||digital | || OR || ||||Signer's || Signed | Digital ||signature | ||+------------+|| ||||Document ||Attributes| signature || | ||| Timestamp ||| |||| || | ||Optional | ||| only over ||| |||+---------++----------+ ||when | ||| complete ||| ||+----------------------------------+|timemarked| ||| certificate||| || +----------+ ||| and ||| || ||| Revocation ||| || +-------------+ ||| References ||| || | Complete | ||+------------+|| || | certificate | |+--------------+| || | and | | +------------+ | || | revocation | | | Complete | | || | references | | |certificate | | || +-------------+ | | and | | |+-------------------------------------------------+ |revocation | | | | value | | | +------------+ | +-------------------------------------------------------------------+ Figure 9: Illustration of CAdES-X Long Type 1 and CAdES Long Type 24.4.44.4.4. Archival Electronic Signature (CAdES-A) Archival Form(CAdES-A)(CAdES-A), in accordance with the presentdocumentdocument, builds on a CAdES-X Long or a CAdES-X Long Type 1 or 2 by adding one or more archive-time-stamp attributes. This form is used for archival oflong- termlong-term signatures. Successive time-stamps protect the whole material against vulnerable hashing algorithms or the breaking of the cryptographic material or algorithms. Section 6.4 contains the specification details. Sections C.4.5 and C.4.8 provide the rationale. The structure of the CAdES-A form is illustrated infigureFigure 10. +---------------------------CAdES-A ---------------------------------+ |+----------------------------------------------------+ | || +--------------+| +----------+ | ||+----------------------CAdES-C ----+|+------------+|| | | | ||| +----------+ ||| Timestamp ||| | | | |||+---- CAdES-BES ----+|Timestamp | ||| over ||| | | | |||| or CAdeS-EPES || over | ||| CAdES-C ||| | Archive | | |||| ||digital | ||+------------+|| | | | |||| ||signature | || or || |Timestamp | | |||| || | ||+------------+|| | | | |||| ||Optional | ||| Timestamp ||| | | | |||| ||when | ||| only over ||| | | | |||| ||Timemarked| ||| complete ||| | | | |||+-------------------+| | ||| certificate||| +----------+ | ||| +----------+ ||| and ||| | ||| +-------------+ ||| revocation ||| | ||| | Complete | ||| references ||| | ||| | certificate | ||+------------+|| | ||| | and | |+--------------+| | ||| | revocation | | +------------+ | | ||| | references | | | Complete | | | ||| +-------------+ | |certificate | | | ||| | | and | | | ||+----------------------------------+ |revocation | | | || | values | | | || +------------+ | | |+----------------------------------------------------+ | +--------------------------------------------------------------------+ Figure 10: Illustration of CAdES-A4.54.5. Arbitration The CAdES-C may be used for arbitration should there be a dispute between the signer and verifier, provided that: - the arbitrator knows where to retrieve the signer's certificate (if not already present), all the cross-certificates and the required CRLs,ACRLsACRLs, or OCSP responses referenced in the CAdES-C; - when time-stamping in the CAdES-T is being used, the certificate from the TSU that has issued the time-stamp token in the CAdES-T format is still within its validity period; - when time-stamping in the CAdES-T is being used, the certificate from the TSU that has issued the time-stamp token in the CAdES-T format is not revoked at the time of arbitration; - when time-marking in the CAdES-T is being used, a reliable audit trail from the Time-Marking Authority is available for examination regarding the time; - none of the private keys corresponding to the certificates used to verify the signature chain have ever been compromised; - the cryptography used at the time the CAdES-C was built has not been broken at the time the arbitration is performed; and -Ifif the signature policy can beexplicitexplicitly or implicitlyidentifiedidentified, then an arbitrator is able to determine the rules required to validate the electronic signature.4.6 Validation process The4.6. Validation Process The validation process validates an electronicsignature,signature; the output status of the validation process can be: - invalid; - incomplete validation; or - valid. AnInvalidinvalid response indicates that either the signature format is incorrect or that the digital signature value fails verification(e.g.(e.g., the integrity check on the digital signature valuefailsfails, or any of the certificates on which the digital signature verification depends is known to be invalid or revoked). AnIncomplete Validationincomplete validation response indicates that the signature validation status is currently unknown. In the case of incomplete validation, additional information may be made available to the application or user, thus allowing them to decide what to do with the electronic signature. In the case of incomplete validation, the electronic signature may be checked again at some later time when additional information becomes available. NOTE: Forexample;example, an incomplete validation may be because all the required certificates are not available or the grace period is not completed. AValidvalid response indicates that the signature has passedverificationverification, and it complies with the signature validation policy. Example validation sequences are illustrated inannexAnnex B.55. Electronicsignature attributesSignature Attributes This section builds upon the existing Cryptographic Message Syntax (CMS), as defined in RFC 3852 [4], and Enhanced Security Services (ESS), as defined in RFC 2634 [5]. The overall structure of an Electronic Signature is as defined in CMS. The Electronic Signature (ES) uses attributes defined in CMS,ESSESS, and the present document. The present document defines ES attributeswhichthat it uses and that are not defined elsewhere. The mandated set of attributes and the digital signature value is defined as the minimum Electronic Signature (ES) required by the present document. A signature policy may mandate that other signed attributesarebe present.5.15.1. GeneralsyntaxSyntax The general syntax of the ES is as defined in CMS (RFC 3852 [4]). NOTE: CMS defines content types for id-data, id-signedData,id- envelopedData,id-envelopedData, id-digestedData, id-encryptedData, andid- authenticatedData.id-authenticatedData. Although CMS permits other documents to define other content types, the ASN.1 type defined should not be a CHOICE type. The present document does not define other content types.5.25.2. Datacontent typeContent Type The data content type of the ES is as defined in CMS (RFC 3852 [4]). NOTE: If the content type is id-data, it is recommended that the contentisbe encoded usingMIMEMIME, and that the MIME type is used to identify the presentation format of the data. SeeannexAnnex F.1 for an example of using MIME to identify the encoding type.5.35.3. Signed-datacontent typeContent Type Thesigned-dataSigned-data content type of the ES is as defined in CMS (RFC 3852 [4]).5.45.4. SignedDatatypeType The syntax of the SignedData of the ES is as defined in CMS (RFC 3852 [4]). The fields of type SignedDatahave the meaningsare as defined in CMS (RFC 3852 [4]). The identification of a signer's certificate used to create the signature is always signed (seesectionSection 5.7.3). The validation policy may specify requirements for the presence of certain certificates. The degeneratecasecase, where there are nosignerssigners, is not valid in the present document.5.55.5. EncapsulatedContentInfotypeType The syntax of the EncapsulatedContentInfo type ES is as defined in CMS (RFC 3852 [4]). For the purpose oflong term validationlong-term validation, as defined by the present document, it is advisable that either the eContent is present, or the datawhichthat is signed is archived in such as way as to preserve any data encoding. It is important that the OCTET STRING used to generate the signature remains the same every time either the verifier or an arbitrator validates the signature. NOTE: The eContent is optional in CMS : - When it is present, this allows the signed data to be encapsulated in the SignedData structure, which then contains both the signed data and the signature. However, the signed data may only be accessed by a verifier able to decode the ASN.1 encoded SignedData structure. - When it is missing, this allows the signed data to be sent or stored separately from thesignaturesignature, and the SignedData structure only contains the signature. Itisis, in the case ofsignaturethe signature, onlythatthe datawhichthat is signed that needs to be stored and distributed in such as way as to preserve any data encoding. The degenerate case where there are no signers is not valid in the present document.5.65.6. SignerInfotypeType The syntax of the SignerInfo type ES is as defined in CMS (RFC 3852 [4]). Per-signer information is represented in the type SignerInfo. In the case of multiple independent signatures (seesectionAnnex B.5), there is an instance of this field for each signer. The fields of type SignerInfo have the meanings defined in CMS (RFC 3852[4])[4]), but the signedAttrs field shall contain the following attributes: -content-typecontent-type, as defined insectionSection 5.7.1; and -message-digestmessage-digest, as defined insectionSection 5.7.2; -signing-certificatesigning-certificate, as defined insectionSection 5.7.3.5.6.15.6.1. Messagedigest calculation processDigest Calculation Process The message digest calculation process is as defined in CMS (RFC 3852 [4]).5.6.25.6.2. Messagesignature generation processSignature Generation Process The input to the message signature generation process is as defined in CMS (RFC 3852 [4]).5.6.35.6.3. Messagesignature verification processSignature Verification Process The procedures for message signature verification are defined in CMS (RFC 3852 [4]) and enhanced in the present document: the input to the signature verification process must be the signer's publickeykey, which shall be verified as correct using the signing certificate reference attribute containing a reference to the signing certificate,i.e.i.e., when SigningCertificateV2 from RFC 5035 [16] or SigningCertificate from ESS [5] is used, the public key from the first certificate identified in the sequence of certificate identifiers from SigningCertificate must be the key used to verify the digital signature.5.75.7. Basic ESmandatory present attributesMandatory Present Attributes The following attributes shall be present with the signed-data defined by the present document. The attributes are defined in CMS (RFC 3852 [4]).5.7.1 Content type5.7.1. content-type The content-type attribute indicates the type of the signed content. The syntax of the content-type attribute type is as defined in CMS (RFC 3852 [4])sectionSection 11.1.Note 1 :NOTE 1: As stated in RFC 3852 [4] , the content-type attribute must have its value(i.e.(i.e., ContentType) equal to the eContentType of the EncapsulatedContentInfo value being signed.Note 2 :NOTE 2: For implementations supporting signature generation, if the content-type attribute is id-data, then it is recommended that the eContent be encoded using MIME. For implementations supporting signature verification, if the signed data(i.e.(i.e., eContent) is MIME-encoded, then the OID of the content-type attribute must be id-data. In both cases, the MIME content-type(s) must be used to identify the presentation format of the data. See Annex F for further details about the use of MIME.5.7.25.7.2. MessagedigestDigest The syntax of the message-digest attribute type of the ES is as defined in CMS (RFC 3852 [4]).5.7.35.7.3. Signingcertificate reference attributesCertificate Reference Attributes The Signing certificate reference attributes are supported by using either the ESS signing-certificate attribute or theESS-signing- certificate-v2ESS-signing-certificate-v2 attribute. These attributes shall contain a reference to the signer'scertificate,certificate; they are designed to preventthesimple substitution andre-issuereissue attacks and to allow for a restricted set of certificates to be used in verifying a signature. They have a compact form (much shorter than the full certificate) that allowstofor a certificate to be unambiguously identified. One, and only one, of the following alternative attributes shall be present with thesignedDatasignedData, defined by the presentdocument.document: - The ESS signing-certificate attribute, defined in ESS [5], must be used if the SHA-1 hashing algorithm is used. - The ESSsigning-certificate attribute v2,signing-certificate-v2 attribute, defined in "ESS Update: Adding CertID Algorithm Agility", RFC 5035[15][15], which shall be used when other hashing algorithms are to be used. The certificate to be used to verify the signature shall be identified in the sequence(i.e.(i.e., the certificate from thesigner)signer), and the sequence shall not be empty. The signature validation policy may mandate other certificates be present that may include all the certificates up to the trust anchor.5.7.3.15.7.3.1. ESSsigning certificate attribute definitionsigning-certificate Attribute Definition The syntax of the signing-certificate attribute type of the ES is as defined in Enhanced Security Services (ESS), RFC 2634[5][5], and further qualified in the present document. The sequence of the policy information field is not used in the present document. The ESS signing-certificate attribute shall be a signed attribute. The encoding of the ESSCertID for this certificate shall include the issuerSerial field. If present, the issuerAndSerialNumber in SignerIdentifier field of the SignerInfo shall match the issuerSerial field present in ESSCertID. Inadditionaddition, the certHash from ESSCertID shall match the SHA-1 hash of the certificate. The certificate identified shall be used during the signature verification process. If the hash of the certificate does not match the certificate used to verify the signature, the signature shall be considered invalid. NOTE: Where an attribute certificate is used by the signer to associate a role, or other attributes of the signer, with the electronicsignature,signature; this is placed in the signer-attributes attribute as defined insectionSection 5.8.3.5.7.3.25.7.3.2. ESSsigning certificate v2 attribute definitionsigning-certificate-v2 Attribute Definition The ESSsigning-certificate v2signing-certificate-v2 attribute is similar to the ESS signing-certificate defined above, except that this attribute can be used with hashing algorithms other than SHA-1. The syntax of thesigning-certificate v2signing-certificate-v2 attribute type of the ES is as defined in "ESS Update: Adding CertID Algorithm Agility", RFC 5035[15][15], and further qualified in the present document. The sequence of the policy information field is not used in the present document. This attribute shall be used in the same manner as defined above for the ESS signing-certificate attribute. The object identifier for this attribute is: id-aa-signingCertificateV2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 47 } If present, the issuerAndSerialNumber in SignerIdentifier field of the SignerInfo shall match the issuerSerial field present in ESSCertID. Inadditionaddition, the certHash from ESSCertID shall match the SHA-1 hash of the certificate. The certificate identified shall be used during the signature verification process. If the hash of the certificate does not match the certificate used to verify the signature, the signature shall be considered invalid.Note 1 :NOTE 1: Where an attribute certificate is used by the signer to associate a role, or other attributes of the signer, with the electronicsignature,signature; this is placed in the signer-attributes attribute as defined insectionSection 5.8.3.Note 2 :NOTE 2: RFC 3126 was using the othersigning certificatesigning-certificate attribute (seesectionSection 5.7.3.3) for the same purpose. Its use is now deprecated, since this structure is simpler.5.7.3.35.7.3.3. Othersigning certificate attribute definitionsigning-certificate Attribute Definition RFC 3126 was using the othersigning certificatesigning-certificate attribute as an alternative to the ESS signing-certificate when hashing algorithms other than SHA-1 were being used. Its use is now deprecated, since the structure of thegeneral-signing-certificate-v2signing-certificate-v2 attribute is simpler. Its description is however still present in this version for backwards compatibility. id-aa-ets-otherSigCert OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 19 } The other-signing-certificate attribute value has the ASN.1 syntax OtherSigningCertificate: OtherSigningCertificate ::= SEQUENCE { certs SEQUENCE OF OtherCertID, policies SEQUENCE OF PolicyInformation OPTIONAL -- NOT USED IN THE PRESENT DOCUMENT } OtherCertID ::= SEQUENCE { otherCertHash OtherHash, issuerSerial IssuerSerial OPTIONAL } OtherHash ::= CHOICE { sha1Hash OtherHashValue, -- This contains a SHA-1 hash otherHash OtherHashAlgAndValue} OtherHashValue ::= OCTET STRING OtherHashAlgAndValue ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, hashValue OtherHashValue }5.85.8. Additionalmandatory attributesMandatory Attributes for Explicit Policy-based Electronic Signatures5.8.1 Signature policy identifier5.8.1. signature-policy-identifier The present document mandates that forCAdES-EPESCAdES-EPES, a reference to the signature policy is included in the signedData. This reference is explicitly identified. A signature policy defines the rules for creation and validation of an electronic signature, and is included as a signed attribute with every Explicit Policy-based Electronic Signature. The signature-policy-identifier shall be a signed attribute. The following object identifier identifies the signature-policy-identifier attribute: id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 15 } signature-policy-identifier attribute values have ASN.1 type SignaturePolicyIdentifier: SignaturePolicyIdentifier ::= CHOICE { signaturePolicyId SignaturePolicyId, signaturePolicyImplied SignaturePolicyImplied -- not used in this version } SignaturePolicyId ::= SEQUENCE { sigPolicyId SigPolicyId, sigPolicyHash SigPolicyHash, sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF SigPolicyQualifierInfo OPTIONAL} SignaturePolicyImplied ::= NULL The sigPolicyId field contains an object-identifierwhichthat uniquely identifies a specific version of the signature policy. The syntax of this field is as follows: SigPolicyId ::= OBJECT IDENTIFIER The sigPolicyHash field optionally contains the identifier of the hash algorithm and the hash of the value of the signature policy. The hashValue within the sigPolicyHash may be set to zero to indicate that the policy hash value is not known. NOTE: The use ofzero policythe zero-policy hash value is to ensurebackwardbackwards compatibility with earlier versions of the current document. If hashValue iszerozero, then the hash value should not be checked against the calculated hash value of the signature policy. If the signature policy is defined using ASN.1, then the hash is calculated on the value without the outer type and lengthfieldsfields, and the hashing algorithm shall be as specified in the field sigPolicyHash. If the signature policy is defined using another structure, the type of structure and the hashing algorithm shall be either specified as part of the signature policy, or indicated using a signature policy qualifier. SigPolicyHash ::= OtherHashAlgAndValue OtherHashAlgAndValue ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, hashValue OtherHashValue } OtherHashValue ::= OCTET STRING Asignature policy identifierSignature Policy Identifier may be qualified with other information about the qualifier. The semantics and syntax of the qualifier is as associated with the object-identifier in the sigPolicyQualifierId field. The general syntax of this qualifier is as follows: SigPolicyQualifierInfo ::= SEQUENCE { sigPolicyQualifierId SigPolicyQualifierId, sigQualifier ANY DEFINED BY sigPolicyQualifierId } The present document specifies the following qualifiers: - spuri: this contains the web URI or URL reference to the signature policy, and - sp-user-notice: this contains a user noticewhichthat should be displayed whenever the signature is validated. sigpolicyQualifierIds defined in the present document: SigPolicyQualifierId ::= OBJECT IDENTIFIER id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 1 } SPuri ::= IA5String id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 2 } SPUserNotice ::= SEQUENCE { noticeRef NoticeReference OPTIONAL, explicitText DisplayText OPTIONAL} NoticeReference ::= SEQUENCE { organization DisplayText, noticeNumbers SEQUENCE OF INTEGER } DisplayText ::= CHOICE { visibleString VisibleString (SIZE (1..200)), bmpString BMPString (SIZE (1..200)), utf8String UTF8String (SIZE (1..200)) }5.95.9. CMSimported optional attributesImported Optional Attributes The following attributes may be present with thesigned-data,signed-data; the attributes are defined in CMS (RFC 3852 [4]) and are imported into the present document.Were appropriatedWhere appropriate, the attributes are qualified and profiled by the present document.5.9.1 Signing time5.9.1. signing-time The signing-time attribute specifies the time at which the signer claims to have performed the signing process. Signing-time attribute values for ES have the ASN.1 type SigningTime as defined in CMS (RFC 3852 [4]). NOTE: RFC 3852 [4] states that dates between1January 1, 1950 and31December 31, 2049 (inclusive) must be encoded as UTCTime. Any dates with year values before 1950 or after 2049 must be encoded as GeneralizedTime.5.9.2 Countersignature5.9.2. countersignature ThecounterSignaturecountersignature attribute values for ES have ASN.1 typeCounterSignatureCounterSignature, as defined in CMS (RFC 3852 [4]). AcounterSignaturecountersignature attribute shall be an unsigned attribute.5.10 ESS imported optional attributes5.10. ESS-Imported Optional Attributes The following attributes may be present with the signed-data defined by the present document. The attributes are defined in ESS and are imported into the present document and wereappropriateappropriately qualified and profiled by the present document.5.10.1 Content reference attribute5.10.1. content-reference Attribute The content-reference attribute is a link from one SignedData to another. It may be used to link a reply to the original message to which it refers, or to incorporate by reference one SignedData into another. The content-reference attribute shall be a signed attribute.Content-referencecontent-reference attribute values for ES have ASN.1 typeContentReferenceContentReference, as defined in ESS (RFC 2634 [5]). The content-reference attribute shall be used as defined in ESS (RFC 2634 [5]).5.10.2 Content identifier attribute5.10.2. content-identifier Attribute The content-identifier attribute provides an identifier for the signedcontentcontent, for use when a reference may be later required to thatcontent,content; forexampleexample, in thecontent referencecontent-reference attribute in other signed data sent later. The content-identifier shall be a signed attribute. content-identifier attribute type values forofthe ES have an ASN.1 typeContentIdentifierContentIdentifier, as defined in ESS (RFC 2634 [5]). The minimal content-identifier attribute should contain a concatenation of user-specific identification information (such as a user name or public keying material identification information), a GeneralizedTime string, and a random number.5.10.3 Content hints attribute5.10.3. content-hints Attribute The content-hints attribute provides information on the innermost signed content of a multi-layer message where one content is encapsulated in another. The syntax of the content-hints attribute type of the ES is as defined in ESS (RFC 2634 [5]). When used to indicate the precise format of the data to be presented to theuseruser, the following rules apply: - the contentType indicates the type of the associated content. It is an object identifier(i.e.(i.e., a unique string of integers) assigned by an authority that defines the content type; and - when the contentType is id-data, the contentDescription shall define the presentationformat,format; the format may be defined by MIME types. When the format of the content is defined by MIMEtypestypes, the following rules apply: - the contentType shall beid-dataid-data, as defined in CMS (RFC 3852 [4]); - the contentDescription shall be used to indicate the encoding of thedatadata, in accordance with the rules defined RFC 2045[6],[6]; seeannexAnnex F for an example of structured contents and MIME. NOTE 1: id-data OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs7(7) 1 } NOTE 2: contentDescription is optional in ESS (RFC 2634 [5]). It may be used to complement contentTypes definedelsewhere ,elsewhere; such definitions are outside the scope of the present document.5.115.11. Additionaloptional attributes definedOptional Attributes Defined in thepresent documentPresent Document This section defines a number of attributes that may be used to indicate additional information to averifier :verifier: a) the type of commitment from the signer, and/or b) the claimed location where the signature is performed, and/or c) claimed attributes or certified attributes of the signer, and/or d) a content time-stamp applied before the content was signed.5.11.1 Commitment type indication attribute5.11.1. commitment-type-indication Attribute There may be situations where a signer wants to explicitly indicate to a verifier that by signing the data, it illustrates a type of commitment on behalf of the signer. The commitment-type-indication attribute conveys such information. The commitment-type-indication attribute shall be a signed attribute. The commitment type may be: - defined as part of the signature policy, in whichcasecase, the commitment type has precise semantics thatisare defined as part of the signature policy; and - be a registered type, in whichcasecase, the commitment type has precise semantics defined by registration, under the rules of the registration authority. Such a registration authority may be a trading association or a legislative authority. The signature policy specifies a set of attributes that it "recognizes". This "recognized" set includes all those commitment types defined as part of the signaturepolicypolicy, as well as any externally defined commitment types that the policy may choose to recognize. Only recognized commitment types are allowed in this field. The following object identifier identifies thecommitment-type- indicationcommitment-type-indication attribute: id-aa-ets-commitmentType OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 16} commitment-type-indication attribute values have ASN.1 type CommitmentTypeIndication. CommitmentTypeIndication ::= SEQUENCE { commitmentTypeId CommitmentTypeIdentifier, commitmentTypeQualifier SEQUENCE SIZE (1..MAX) OF CommitmentTypeQualifier OPTIONAL} CommitmentTypeIdentifier ::= OBJECT IDENTIFIER CommitmentTypeQualifier ::= SEQUENCE { commitmentTypeIdentifier CommitmentTypeIdentifier, qualifier ANY DEFINED BY commitmentTypeIdentifier } The use of any qualifiers to the commitment type is outside the scope of the present document. The following generic commitment types are defined in the present document: id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 1} id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 2} id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 3} id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 4} id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 5} id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 6} These generic commitment types have the followingmeaning:meanings: Proof of origin indicates that the signer recognizes to have created,approvedapproved, and sent the message. Proof of receipt indicates that signer recognizes to have received the content of the message. Proof of delivery indicates that the TSP providing that indication has delivered a message in a local store accessible to the recipient of the message. Proof of sender indicates that the entity providing that indication has sent the message (but not necessarily created it). Proof of approval indicates that the signer has approved the content of the message. Proof of creation indicates that the signer has created the message (but not necessarily approved, nor sent it).5.11.2 Signer location attribute5.11.2. signer-location Attribute The signer-location attribute specifies a mnemonic for an address associated with the signer at a particular geographical(e.g.(e.g., city) location. The mnemonic is registered in the country in which the signer is located and is used in the provision of the Public Telegram Service (according to ITU-T Recommendation F.1 [11]). The signer-location attribute shall be a signed attribute. The following object identifier identifies the signer-location attribute: id-aa-ets-signerLocation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 17} Signer-location attribute values have ASN.1 type SignerLocation: SignerLocation ::= SEQUENCE { -- at least one of the following shall bepresentpresent: countryName [0] DirectoryString OPTIONAL, -- As used to name a Country in X.500 localityName [1] DirectoryString OPTIONAL, -- As used to name a locality in X.500 postalAdddress [2] PostalAddress OPTIONAL } PostalAddress ::= SEQUENCE SIZE(1..6) OF DirectoryString5.11.3 Signer attributes attribute5.11.3. signer-attributes Attribute The signer-attributes attribute specifies additional attributes of the signer(e.g.(e.g., role). It may be either: - claimed attributes of the signer; or - certified attributes of the signer. The signer-attributes attribute shall be a signed attribute. The following object identifier identifies the signer-attribute attribute: id-aa-ets-signerAttr OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 18} signer-attributes values have ASN.1 type SignerAttribute: SignerAttribute ::= SEQUENCE OF CHOICE { claimedAttributes [0] ClaimedAttributes, certifiedAttributes [1] CertifiedAttributes } ClaimedAttributes ::= SEQUENCE OF Attribute CertifiedAttributes ::= AttributeCertificate -- as defined in RFC3281 :3281: seesectionSection 4.1. NOTE 1: Only a single signer-attributes can be used NOTE 2: The claimedAttributes and certifiedAttributes fields are as defined in ITU-T Recommendations X.501 [9] and X.509 [1].5.11.4 Content time-stamp5.11.4. content-time-stamp The content-time-stamp attribute is an attributewhichthat is thetime- stamptime-stamp token of the signed data content before it is signed. The content-time-stamp attribute shall be a signed attribute. The following object identifier identifies the content-time-stamp attribute: id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) member- body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 20}Content-time-stampcontent-time-stamp attribute values have ASN.1 type ContentTimestamp: ContentTimestamp ::= TimeStampToken The value of messageImprint of TimeStampToken (as described in RFC 3161 [7]) shall be a hash of the value of the eContent field within encapContentInfo in the signedData. For further information and definition ofTimeStampTokenTimeStampToken, seesectionSection 7.4. NOTE:Content-time-stampcontent-time-stamp indicates that the signed information was formed before the date included in theContent-time-stamp. 5.12content-time-stamp. 5.12. Support formultiple signatures 5.12.1Multiple Signatures 5.12.1. IndependentsignaturesSignatures Multiple independent signatures (seesectionAnnex B.5) are supported by independent SignerInfo from each signer. Each SignerInfo shall include all the attributes required under the present document and shall be processed independently by the verifier.Note:NOTE: Independent signatures may be used to provide independent signatures from different parties with different signed attributes, or to provide multiple signatures from the same party using alternative signaturealgorithmsalgorithms, in which case the other attributes, excluding time values and signature policy information, will generally be the same.5.12.25.12.2. EmbeddedsignaturesSignatures Multiple embedded signatures (seesectionAnnex C.5) are supported using the countersignature unsigned attribute (seesectionSection 5.9.2). Each counter signature is carried inCountersignaturecountersignature held as an unsigned attribute to the SignerInfo to which the counter-signature is applied.Note:NOTE: Counter signatures may be used to provide signatures from different parties with different signed attributes, or to provide multiple signatures from the same party using alternative signaturealgorithmsalgorithms, in which case the other attributes, excluding time values and signature policy information, will generally be the same.66. Additional Electronic Signaturevalidation attributesValidation Attributes This section specifies attributes that contain different types of validation data. These attributes build on the electronic signature specified insectionSection 5. This includes: - Signature-time-stamp applied to the electronic signature value or a Time-Mark in an audit trail. This is defined as the Electronic Signature withTimeTime-stamp (CAdES-T); and -completeComplete validation data referenceswhich comprisesthat comprise thetime- stamptime-stamp of the signature value (CAdES-T), plus references to all the certificates (complete-certificate-references) and revocation (complete-revocation-references) information used for full validation of the electronic signature. This is defined as the Electronic Signature with Complete data references (CAdES-C). NOTE 1: Formats for CAdES-T are illustrated insection 4.4Section 4.4, and theattributeattributes are defined insectionSection 6.1.1. NOTE 2: Formats for CAdES-C are illustrated insectionSection 4.4. The required attributes for the CAdES-C signature format are defined insectionSections 6.2.1 to6.2.2,6.2.2; optional attributes are defined insectionsSections 6.2.3 and 6.2.4. Inadditionaddition, the following optionaleXtendedextended forms of validation data are alsodefined,defined; seeannexAnnex B for an overview of theeXtendedextended forms of validation data: - CAdES-X withtime stamp:time-stamp: there are two types oftime-stamptime-stamps used in extended validation data defined by the presentdocument:document; - Type 1(CAdES-X Type 1): comprises a time-stamp over the ES withcompleteComplete validation data (CAdES-C); and - Type 2 (CAdES-X Type2): comprises a time-stamp over the certification path references and the revocation information references used to support the CAdES-C. NOTE 3: Formats for CAdES-X Type 1 and CAdES-X Type 2 are illustrated insectionsSections B.1.2 and B.1.3, respectively. - CAdES-XLong :comprisesLong: comprises thecompleteComplete validation data references(CAdES-C)(CAdES-C), plus the actual values of all the certificates and revocation information used in the CAdES-C. NOTE 4: Formats for CAdES-X Long are illustrated insectionAnnex B.1.1. - CAdES-X Long Type 1 or CAdES-X Long Type 2: comprises anX-Time- StampX-Time-Stamp (Type 1 or Type2)2), plus the actual values of all the certificates and revocation information used in the CAdES-C as per CAdES-X Long. This section also specifies the data structures used in Archive validation data format (CAdES-A)ofeXtendedextended forms: - Archive form of electronic signature (CAdES-A)comprisescomprises: - thecompleteComplete validation data references (CAdES-C), - the certificate and revocation values (as in a CAdES-X Long ),if present- any existing extended electronic signaturetimestampstime-stamps (CAdES-X Type 1 or CAdES-X Type 2),plusif present, and - the signed user data and an additional archive time-stamp applied over all that data. An archivetime- stamptime-stamp may be repeatedly applied after long periods to maintain validity when electronic signature and time-stamping algorithms weaken. The additional data required to create the forms of electronic signature identified above is carried as unsigned attributes associated with an individual signature by being placed in the unsignedAttrs field of SignerInfo.ThusThus, all the attributes defined insectionSection 6 are unsigned attributes. NOTE 5: Where multiple signatures are to be supported, as described insectionSection 5.12, each signature has a separate SignerInfo. Thus, each signature requires its own unsigned attribute values to create CAdES-T, CAdES-C, etc. NOTE 6:theThe optional attributes of the extended validation data are defined insectionsSections 6.3 and 6.4.6.1 Electronic Signature Time-stamped6.1. signature time-stamp Attribute (CAdES-T) AnElectronic Signatureelectronic signature with time-stamp is an electronic signature for which part, but not all, of the additional data required for validation is available(i.e.(i.e., some certificates and revocation information areavailableavailable, but not all). The minimum structure time-stamp validation data is: - theSignature Time-stamp Attributesignature time-stamp attribute, as defined insection 6.1.1Section 6.1.1, over the ES signature value.6.1.1 Signature time- stamp attribute definition6.1.1. signature-time-stamp Attribute Definition The signature-time-stamp attribute is a TimeStampToken computed on the signature value for a specificsigner. Itsigner; it is an unsigned attribute. Several instances of this attribute may occur with an electronic signature, from different TSAs. The following object identifier identifies the signature-time-stamp attribute: id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 14} The signature-time-stamp attribute value has ASN.1 type SignatureTimeStampToken: SignatureTimeStampToken ::= TimeStampToken The value of the messageImprint field within TimeStampToken shall be a hash of the value of the signature field within SignerInfo for the signedData being time-stamped. For further information and definition ofTimeStampTokenTimeStampToken, seesectionSection 7.4. NOTE 1: In the case of multiplesignaturessignatures, it is possible to haveaa: - TimeStampToken computed for each and allsigners,signers; or - TimeStampToken computed on one signer'ssignaturesignature; and no - TimeStampToken on another signer's signature. NOTE 2: In the case of multiple signatures, several TSTs, issued by different TSAs, may be present within the same signerInfo (see RFC 3852 [4]).6.26.2. Completevalidation reference dataValidation Data References (CAdES-C) An electronic signature withcompleteComplete validation data references (CAdES-C) is anElectronic Signatureelectronic signature for which all the additional data required for validation(i.e.(i.e., all certificates and revocation information) is available. This form is built on the CAdES-T form defined above. As a minimum, thecompleteComplete validation data shall include the following: - a time, which shall either be a signature-timestamp attribute, as defined insectionSection 6.1.1, or atime marktime-mark operated by aTime- MarkingTime-Marking Authority; - complete-certificate-references, as defined insectionSection 6.2.1; -complete-revocation-references ,complete-revocation-references, as defined insectionSection 6.2.2.6.2.1 Complete certificate references attribute definition6.2.1. complete-certificate-references Attribute Definition The complete-certificate-references attribute is an unsigned attribute. It references the full set of CA certificates that have been used to validate an ES with Complete validation data up to (but not including) the signer's certificate. Only a single instance of this attribute shall occur with an electronic signature. NOTE 1: The signer's certificate is referenced in the signing certificate attribute (seesectionSection 5.7.3). id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 21} Thecomplete-certificate-referencescomplete-certificate-referneces attribute value has the ASN.1 syntax CompleteCertificateRefs. CompleteCertificateRefs ::= SEQUENCE OF OtherCertID OtherCertID is defined insectionSection 5.7.3.2. The IssuerSerial that shall be present in OtherCertID. The certHash shall match the hash of the certificate referenced. NOTE 2: Copies of the certificate values may be held using the certificate-valuesattributeattribute, defined insectionSection 6.3.3. This attribute may include references to the certification chain for any TSUs that provides time-stamp tokens. In thiscasecase, the unsigned attribute shall be added to the signedData of the relevanttimes tamptime-stamp token as an unsignedAttrs in the signerInfos field.6.2.2 Complete Revocation References attribute definition6.2.2. complete-revocation-references Attribute Definition The complete-revocation-references attribute is an unsigned attribute. Only a single instance of this attribute shall occur with an electronic signature. It references the full set of the CRL,ACRLACRL, or OCSP responses that have been used in the validation of thesignersigner, and CA certificates used in ES with Complete validation data. This attributecan be used to illustrateindicates that the verifier has taken due diligenceofto gather the available revocationinformation and then toinformation. The references stored in this attribute can beableused to retrievethat information whenthe referenced information, if not storedelsewhere.in the CMS structure, but somewhere else. The following object identifier identifies thecomplete-revocation- referencescomplete-revocation-references attribute: id-aa-ets-revocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 22} The complete-revocation-references attribute value has the ASN.1 syntax CompleteRevocationRefs: CompleteRevocationRefs ::= SEQUENCE OF CrlOcspRef CrlOcspRef ::= SEQUENCE { crlids [0] CRLListID OPTIONAL, ocspids [1] OcspListID OPTIONAL, otherRev [2] OtherRevRefs OPTIONAL } CompleteRevocationRefs shall contain one CrlOcspRef for thesigning- certificate,signing-certificate, followed by one for each OtherCertID in the CompleteCertificateRefs attribute. The second and subsequent CrlOcspRef fields shall be in the same order as the OtherCertID to which they relate. At least one of CRLListID or OcspListID or OtherRevRefs should be present for all but the "trusted" CA of the certificate path. CRLListID ::= SEQUENCE { crls SEQUENCE OF CrlValidatedID } CrlValidatedID ::= SEQUENCE { crlHash OtherHash, crlIdentifier CrlIdentifier OPTIONAL } CrlIdentifier ::= SEQUENCE { crlissuer Name, crlIssuedTime UTCTime, crlNumber INTEGER OPTIONAL } OcspListID ::= SEQUENCE { ocspResponses SEQUENCE OF OcspResponsesID } OcspResponsesID ::= SEQUENCE { ocspIdentifier OcspIdentifier, ocspRepHash OtherHash OPTIONAL } OcspIdentifier ::= SEQUENCE { ocspResponderID ResponderID, -- As in OCSP response data producedAt GeneralizedTime -- As in OCSP response data } When creating a crlValidatedID, the crlHash is computed over the entire DER encoded CRL including the signature. The crlIdentifier would normally be present unless the CRL can be inferred from other information. The crlIdentifier is to identify the CRL using the issuer name and theCRL issuedCRL-issued time, which shall correspond to the time thisUpdate contained in the issued CRL, and if present, the crlNumber. The crlListID attribute is an unsigned attribute. In the case that the identified CRL is a DeltaCRLCRL, then references to the set of CRLs to provide a complete revocation list shall be included. The OcspIdentifier is to identify the OCSP response using the issuer name and the time of issue of the OCSPresponseresponse, which shall correspond to the timeproducedAtproduced as contained in the issued OCSP response. Since it may be needed to make the difference between two OCSP responses received within the same second,thenthe hash of the response contained in the OcspResponsesID may be needed to solve the ambiguity. NOTE 1: Copies of the CRL and OCSP responses values may be held using the revocation-values attribute defined insectionSection 6.3.4. NOTE 2: It is recommended that this attributeisbe used in preference toThethe OtherRevocationInfoFormat specified in RFC 3852 toMaintain backwardmaintain backwards compatibility with the earlier version of this specification. The syntax and semantics of other revocation referencesisare outside the scope of the present document. The definition of the syntax of the other form of revocation information is as identified by OtherRevRefType. This attribute may include the references to the full set of the CRL,ACRLACRL, or OCSP responses that have been used to verify the certification chain for any TSUs thatprovidesprovide time-stamp tokens. In thiscasecase, the unsigned attribute shall be added to the signedData of the relevanttimestamptime-stamp token as an unsignedAttrs in the signerInfos field.6.2.36.2.3. attribute-certificate-references Attributecertificate references attribute definitionDefinition This attribute is only used when a user attribute certificate is present in the electronic signature. The attribute-certificate-references attribute is an unsigned attribute. It references the full set of AA certificates that have been used to validate the attribute certificate. Only a single instance of this attribute shall occur with an electronic signature. id-aa-ets-attrCertificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 44} The attribute-certificate-references attribute value has the ASN.1 syntax AttributeCertificateRefs: AttributeCertificateRefs ::= SEQUENCE OF OtherCertID OtherCertID is defined insectionSection 5.8.2. NOTE: Copies of the certificate values may be held using the certificate-values attribute defined insectionSection 6.3.3.6.2.46.2.4. attribute-revocation-references Attributerevocation references attribute definitionDefinition This attribute is only used when a user attribute certificate is present in the electronic signature and when that attribute certificate can be revoked. The attribute-revocation-references attribute is an unsigned attribute. Only a single instance of this attribute shall occur with an electronic signature. It references the full set of the ACRL or OCSP responses that have been used in the validation of the attribute certificate. This attribute can be used to illustrate that the verifier has taken due diligence of the available revocation information. The following object identifier identifies theattribute-revocation- referencesattribute-revocation-references attribute: id-aa-ets-attrRevocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 45} The attribute-revocation-references attribute value has the ASN.1 syntax AttributeRevocationRefs: AttributeRevocationRefs ::= SEQUENCE OF CrlOcspRef6.36.3. Extendedvalidation dataValidation Data (CAdES-X) This section specifies a number of optional attributes that are used by extended forms of electronic signatures (seeannexAnnex B for an overview of these forms of validation data).6.3.1 Time-stamped validation data6.3.1. Time-Stamped Validation Data (CAdES-X Type 1 or Type 2) The extended validation data may include one of the following additional attributes, forming a CAdES-X Time-Stamp validation data (CAdES-X Type 1 or CAdES-X Type 2), to provide additional protection against later CA compromise and provide integrity of the validation data used: - CAdES-C Time-stamp, as defined insectionSection 6.3.5 (CAdES-X Type 1); or - Time-Stamped Certificates and CRLs references, as defined insectionSection 6.3.6 (CAdES-X Type 2).6.3.26.3.2. Longvalidation dataValidation Data (CAdES-X Long, CAdES-X Long Type 1 or 2) The extended validation data may also include the following additional information, forming a CAdES-X Long, for use if later validation processes may not have access to this information: -certificate-valuescertificate-values, as defined insectionSection 6.3.3; and -revocation-valuesrevocation-values, as defined insectionSection 6.3.4. The extended validation datamaymay, in addition to certificate-values and revocation-values as defined insectionsSections 6.3.3 and6.3.46.3.4, include one of the following additional attributes, formingana CAdES-X Long Type 1 or CAdES-X Long Type 2. - CAdES-C Time-stamp, as defined insectionSection 6.3.3 (CAdES-X long Type 1); or - Time-Stamped Certificates and CRLs references, as defined insectionSection 6.3.4 (CAdES-X Long Type 2). The CAdES-X Long Type 1 or CAdES-X Long Type 2provideprovides additional protection against later CA compromise andprovideprovides integrity of the validation data used. NOTE 1: The CAdES-X-Long signature provideslong termlong-term proof of the validity of the signature for as long as the CA keys, CRL Issuerskeyskeys, and OCSP responder keys are not compromised and are resistant to cryptographic attacks. NOTE 2: As long as thetime stamptime-stamp data remains valid, the CAdES-X Long Type 1 and the CAdES-X Long Type 2providesprovide the following important property forlong standinglong-standing signatures; that having been found once to be valid, it shall continue to be so months or years later, long after the validity period of the certificateshavehas expired, or after the user key has been compromised.6.3.3 Certificate values attribute definition6.3.3. certificate-values Attribute Definition This attribute may be used to contain the certificate information required for the following forms ofeXtended Electronic Signature:extended electronic signature: CAdES-XLong ,Long, ES X-Long Type11, and CAdES-X Long Type2,2; seesectionAnnex B.1.1 for an illustration of this form of electronic signature. The certificate-values attribute is an unsigned attribute. Only a single instance of this attribute shall occur with an electronic signature. It holds the values of certificates referenced in the complete-certificate-references attribute. NOTE: If an attribute certificate is used, it is not provided in this structure but shall be provided by the signer as asigner- attributessigner-attributes attribute (seesectionSection 5.11.3). The following object identifier identifies the certificate-values attribute: id-aa-ets-certValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 23} The certificate-values attribute value has the ASN.1 syntax CertificateValues. CertificateValues ::= SEQUENCE OF Certificate Certificate is defined insectionSection 7.1. (which is as defined in ITU-T Recommendation X.509[1].[1]). This attribute may include the certification information for any TSUs that have provided the time-stamptokenstokens, if these certificates are not already included in the TSTs as part of the TSUs signatures. In thiscasecase, the unsigned attribute shall be added to the signedData of the relevanttimestamptime-stamp token.6.3.4 Revocation values attribute definition6.3.4. revocation-values Attribute Definition This attribute is used to contain the revocation information required for the following forms ofeXtended Electronic Signature:extended electronic signature: CAdES-X Long, ES X-Long Type11, and CAdES-X Long Type2,2; seesectionAnnex B.1.1 for an illustration of this form of electronic signature. The revocation-values attribute is an unsigned attribute. Only a single instance of this attribute shall occur with an electronic signature. It holds the values of CRLs and OCSP referenced in the complete-revocation-references attribute.NOTE :NOTE: It is recommended that this attributeisbe used in preference to the OtherRevocationInfoFormat specified in RFC 3852 to maintainbackwardbackwards compatibility with the earlier version of this specification. The following object identifier identifies the revocation-values attribute: id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 24} The revocation-values attribute value has the ASN.1 syntax RevocationValues RevocationValues ::= SEQUENCE { crlVals [0] SEQUENCE OF CertificateList OPTIONAL, ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL, otherRevVals [2] OtherRevVals OPTIONAL } OtherRevVals ::= SEQUENCE { OtherRevValType OtherRevValType, OtherRevVals ANY DEFINED BY OtherRevValType } OtherRevValType ::= OBJECT IDENTIFIER The syntax and semantics of the other revocation values (OtherRevVals)isare outside the scope of the present document. The definition of the syntax of the other form of revocation information is as identified by OtherRevRefType. CertificateList is defined insectionSection 7.2. (which is as defined in ITU-T Recommendation X.509 [1]). BasicOCSPResponse is defined insectionSection 7.3. (which is as defined in RFC 2560 [3]). This attribute may include the values of revocation data including CRLs andOCSPOCSPs for any TSUs that have provided the time-stamptokenstokens, if these certificates are not already included in the TSTs as part of the TSUs signatures. In thiscasecase, the unsigned attribute shall be added to the signedData of the relevanttimestamp token. 6.3.5 CAdES-Ctime-stampattribute definitiontoken. 6.3.5. CAdES-C-time-stamp Attribute Definition This attribute is used to protect against CA key compromise. This attribute is used for thetime stampingtime-stamping of the complete electronic signature (CAdES-C). It is used in the following forms ofeXtended Electronic Signature;extended electronic signature; CAdES-X Type 1 and CAdES-X Long Type1,1; seesectionAnnex B.1.2 for an illustration of this form of electronic signature. TheCAdES-C-timestampCAdES-C-time-stamp attribute is an unsigned attribute. It is a time-stamp token of the hash of the electronic signature and the complete validation data (CAdES-C). It is aspecial purposespecial-purpose TimeStampToken Attributewhichthat time-stamps the CAdES-C. Several instances of this attribute may occur with an electronic signature from different TSAs. NOTE 1: It is recommended that the attributes being time-stampedarebe encoded in DER. If DER is notemployedemployed, then the binary encoding of theASN.1structuresASN.1 structures being time-stamped should be preserved to ensure that the recalculation of the data hash is consistent. NOTE 2: Each attribute is included in the hash with the attrType and attrValues (including type and length) but without the type and length of the outer SEQUENCE. The following object identifier identifies the CAdES-C-Timestamp attribute: id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 25} The CAdES-C-timestamp attribute value has the ASN.1 syntax ESCTimeStampToken : ESCTimeStampToken ::= TimeStampToken The value of the messageImprint field within TimeStampToken shall be a hash of the concatenated values (without the type or length encoding for that value) of the following data objects: - OCTETSTRING of the SignatureValue field within SignerInfo; - signature-time-stamp, or atime marktime-mark operated by a Time-Marking Authority; - complete-certificate-referencessattribute; and - complete-revocation-references attribute. For further information and definition of the TimeStampToken, seeclauseSection 7.4.6.3.6 Time-stamped certificates and crls references attribute definition6.3.6. time-stamped-certs-crls-references Attribute Definition This attribute is used to protect against CA key compromise. This attribute is used for thetime stampingtime-stamping certificate and revocation references. It is used in the following forms ofeXtended Electronic Signature;extended electronic signature: CAdES-X Type 2 and CAdES-X Long Type2,2; seesectionAnnex B.1.3 for an illustration of this form of electronic signature. A time-stamped-certs-crls-references attribute is an unsigned attribute. It is a time-stamp token issued for a list of referenced certificates and OCSP responsesor/andand/or CRLs to protect against certain CA compromises. Its syntax is as follows: NOTE 1: It is recommended that the attributes being time-stampedarebe encoded in DER. If DER is notemployedemployed, then the binary encoding of theASN.1structuresASN.1 structures being time-stamped should be preserved to ensure that the recalculation of the data hash is consistent. NOTE 2: Each attribute is included in the hash with the attrType and attrValues (including type and length) but without the type and length of the outerSEQUENCESEQUENCE. The following object identifier identifies thetime-stamped-certs-crls- referencestime-stamped-certs-crls-references attribute: id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 26} The attribute value has the ASN.1 syntaxTimestampedCertsCRLs :TimestampedCertsCRLs: TimestampedCertsCRLs ::= TimeStampToken The value of the messageImprint field within the TimeStampToken shall be a hash of the concatenated values (without the type or length encoding for that value) of the following dataobjectsobjects, as present in the ES with Complete validation data (CAdES-C): - complete-certificate-references attribute; and - complete-revocation-references attribute.6.46.4. Archivevalidation dataValidation Data Where an electronic signature is required to last for a very long time, andathe time-stamp token on an electronic signature is in danger of being invalidated due to algorithm weakness or limits in the validity period of the TSA certificate,thenit may be required to time-stamp the electronic signature several times. When this isrequiredrequired, an archive time-stamp attribute may be required for the archive form of the electronic signature (CAdES-A). This archive time-stamp attribute may be repeatedly applied over a period of time.6.4.1 Archive time-stamp attribute definition6.4.1. archive-time-stamp Attribute Definition The archive-time-stamp attribute is a time-stamp token of many of the elements of the signedData in the electronic signature. If the certificate-values and revocation-values attributes are not present in the CAdES-BES or CAdES-EPES, then they shall be added to the electronic signature prior to computing the archive time-stamp token. The archive-time-stamp attribute is an unsigned attribute. Several instances of this attribute may occur with an electronic signature both over time and from different TSUs. The following object identifier identifies the nested archive-time-stamp attribute: id-aa-ets-archiveTimestampV2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 48} Archive-time-stamp attribute values have the ASN.1 syntax ArchiveTimeStampToken ArchiveTimeStampToken ::= TimeStampToken The value of the messageImprint field within TimeStampToken shall be a hash of the concatenation of: -Thethe encapContentInfo element of the SignedData sequence; -If the eContent element of the encapContentInfo is omitted,any external content being protected by thesignature;signature, if the eContent element of the encapContentInfo is omitted; -When present,the Certificates and crls elements of the SignedDatasequence; andsequence, when present, and; -Together withall data elements in the SignerInfo sequence including all signed and unsigned attributes. NOTE 1: An alternative archiveTimestamp attribute, identified by an object identifier { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 27, is defined in prior versions of TS 101 733 [TS101733] and in RFC 3126. The archiveTimestampattributeattribute, defined in versions of TS 101 733 prior to 1.5.1 and in RFC31263126, is not compatible with the attribute defined in the current document. The archiveTimestampattributeattribute, defined in versions 1.5.1 to1.7.31.6.3 of TS 101733733, is compatible with the current document if the content is internal to encapContentInfo. Unless the version of TS 101 733 employed by the signing party is known by all recipients, use of the archiveTimestamp attribute defined in prior versions of TS 101 733 is deprecated. NOTE 2: Counter signatures held as countersignature attributes do not require independent archivetime-stampstime-stamps, as they are protected by the archive time-stamp against the containingsignedDataSignedData structure. NOTE 3: Unless DER is used throughout, it is recommended that the binary encoding of the ASN.1 structures being time-stampedarebe preserved when being archived to ensure that the recalculation of the data hash is consistent. NOTE 4: The hash is calculated over the concatenated data elements asreceived / storedreceived/stored, including the Type and Length encoding. NOTE 5: Whilst it is recommended that unsigned attributesarebe DERencodedencoded, it cannot generally be so guaranteed except by prior arrangement.FurtherFor further information and definition ofTimeStampTokenTimeStampToken, seesectionSection 7.4. The timestamp should be created using stronger algorithms (or longer key lengths) than in the original electronic signatures and weak algorithm (key length) timestamps. NOTE 6: This form of ES also provides protection against a TSP key compromise. The ArchiveTimeStamp will be added as an unsigned attribute in the SignerInfo sequence. For the validation of oneArchiveTimeStampArchiveTimeStamp, the data elements of the SignerInfo must beconcatenatedconcatenated, excluding all later ArchivTimeStampToken attributes. Certificates and revocation information required to validate the ArchiveTimeStamp shall be provided by one of the following methods: - The TSU provides the information in the SignedData of the timestamp token; - Adding the complete-certificate-references attribute and the complete-revocation-references attribute of the TSP as an unsigned attribute within TimeStampToken, when the required information isstorestored elsewhere; or - Adding the certificate-values attribute and the revocation-values attribute of the TSP as an unsigned attribute within TimeStampToken, when the required information isstorestored elsewhere.77. Otherstandard data structures 7.1 Public-key certificate formatStandard Data Structures 7.1. Public Key Certificate Format The X.509 v3 certificate basis syntax is defined in ITU-T Recommendation X.509 [1]. A profile of the X.509 v3 certificate is defined in RFC 3280 [2].7.27.2. Certificaterevocation list formatRevocation List Format The X.509 v2 CRL syntax is defined in ITU-T Recommendation X.509 [1]. A profile of the X.509 v2 CRL is defined in RFC 3280 [2].7.37.3. OCSPresponse formatResponse Format The format of an OCSP token is defined in RFC 2560 [3].7.4 Time-stamp token format7.4. Time-Stamp Token Format The format of a TimeStampToken type is defined in RFC 3161 [7] and profiled in ETSI TS 101 861 [TS101861].7.57.5. Name andattribute formatsAttribute Formats The syntax of the naming and other attributes is defined in ITU-T Recommendation X.509 [1].Note:NOTE: The name used by the signer, held as the subject in the signer's certificate, is allocated and verified on registration with the Certification Authority, either directly or indirectly through a Registration Authority, before being issued with a Certificate. The present document places no restrictions on the form of the name. The subject's name may be a distinguished name, as defined in ITU-T Recommendation X.500 [12], held in the subject field of the certificate, or any other name form held in the subjectAltName certificate extensionfieldfield, as defined in ITU-T Recommendation X.509 [1]. In the case that the subject has no distinguished name, the subject name can be an empty sequence and the subjectAltName extension shall be critical. All Certification Authorities, AttributeAuthoritiesAuthorities, andTime StampingTime-Stamping Authorities shall use distinguished names in the subject field of their certificate. The distinguished name shall include identifiers for the organization providing the service and the legal jurisdiction(e.g.(e.g., country) under which it operates. Where a signer signs as anindividualindividual, but wishes to also identify him/herself as acting on behalf of an organization, it may be necessary to provide two independent forms of identification. The first identity,withwhich is directly associated with the signingkeykey, identifies him/her as an individual. The second, which is managed independently, identifies that person acting as part of the organization, possibly with a given role. In thiscasecase, one of the two identities is carried in the subject/subjectAltName field of the signer's certificate as described above. The present document does not specify the format of the signer's attribute that may be included in public key certificates.NOTE : Signer'sNOTE: The signer's attribute may be supported by using a claimed role in the CMS signed attributes field or by placing an attribute certificate containing a certified role in the CMS signed attributesfield,field; seesectionSection 7.6.7.6 Attribute certificate7.6. AttributeCertificate The syntax of the AttributeCertificate type is defined in RFC 3281 [13]. 8. ConformancerequirementsRequirements For implementations supporting signature generation, the present document defines conformance requirements for the generation of two forms of basic electronic signature, one of the two forms must be implemented. For implementations supporting signature verification, the present document defines conformance requirements for the verification of two forms of basic electronic signature, one of the two forms must be implemented. The present document only defines conformance requirements up to an ES with Complete validation data (CAdES-C). This means that none of the extended and archive forms ofElectronic Signaturethe electronic signature (CAdES-X, CAdES-A) need to be implemented to get conformance to the present document. On verification the inclusion of optional signed and unsigned attributes must be supported only to theextendedextent that the signature is verifiable. The semantics of optional attributes may be unsupported, unless specified otherwise by a signature policy.8.18.1. CAdES-Basic Electronic Signature (CAdES-BES) A system supporting CAdES-BESsignerssigners, according to the presentdocumentdocument, shall, at a minimum, support generation of an electronic signature consisting of the following components: - The general CMS syntax and contenttypetype, as defined in RFC 3852 [4] (seesectionsSections 5.1 and 5.2); - CMSSignedDataSignedData, as defined in RFC 3852[4][4], with the version set to 3 and at least one SignerInfoshall bepresent (seesectionsSections 5.3 to 5.6); - The following CMSattributesattributes, as defined in RFC 3852 [4]: - content-type; this shall always be present (seesectionSection 5.7.1); and - message-digest; this shall always be present (seesectionSection 5.7.2). - One of the followingattributesattributes, as defined in the present document: - signing-certificate: as defined insectionSection 5.7.3.1; or - signing-certificate v2 : as defined insectionSection 5.7.3.2.Note :NOTE: RFC 3126 was using the othersigning certificatesigning-certificate attribute (seesectionSection 5.7.3.3). Its use is now deprecated, since the structure of the signing-certificate v2 attribute is simpler than the othersigning certificatesigning-certificate attribute.8.28.2. CAdES-Explicit Policy-based Electronic Signature A system supporting Policy-basedsignerssigners, according to the presentdocumentdocument, shall, at a minimum, support the generation of an electronic signature consisting of the previous components defined for the basic signer, plus: - The followingattributesattributes, as defined insectionSection 5.9: - signature-policy-identifier; this shall always be present (seesectionSection 5.8.1).8.38.3. Verificationusing time-stampingUsing Time-Stamping A system supportingverifiersverifiers, according to the presentdocumentdocument, with time-stamping facilities shall, at a minimum, support: - verification of the mandated components of an electronic signature, as defined insectionSection 8.1; - signature-time-stamp attribute, as defined insectionSection 6.1.1; -complete-certificate-references, attributecomplete-certificate-references attribute, as defined insectionSection 6.2.1; - complete-revocation-references attribute, as defined insectionSection 6.2.2; - Public Key Certificates, as defined in ITU-T Recommendation X.509 [1] (seesectionSection 8.1); and - either of: - Certificate RevocationLists.Lists, as defined in ITU-T Recommendation X.509 [1] (seesectionSection 8.2); or -on-lineOnline Certificate Status Protocol, as defined in RFC 2560 [3] (seesectionSection 8.3).8.48.4. Verificationusing secure recordsUsing Secure Records A system supportingverifiersverifiers, according to the presentdocumentdocument, shall, at a minimum, support: - verification of the mandated components of an electronic signature, as defined insectionSection 8.1; - complete-certificate-references attribute, as defined insectionSection 6.2.1; - complete-revocation-references attribute, as defined insectionSection 6.2.2; - a record of the electronic signature and the time when the signature was first validated using the referencedcertificatescertificates, and revocation information must bemaintainedmaintained, such that records cannot beundetectableundetectably modified; - Public Key Certificates, as defined in ITU-T Recommendation X.509 [1] (seesectionSection 8.1); and - either of: - Certificate RevocationLists.Lists, as defined in ITU-T Recommendation X.509 [1] (seesectionSection 8.2); or -on-lineonline Certificate Status Protocol, as defined in RFC 2560 [3] (seesectionSection 8.3). 9.IANA Considerations No IANA actions required. 10.References10.19.1. NormativereferencesReferences [1] ITU-T Recommendation X.509 (2000)/ISO/IEC 9594-8 (2001): "Information technology - Open Systems Interconnection - The Directory:AuthenticationPublic key and Attribute Certificate framework". [2]IETF RFC 3280 (2002):Housley, R., Polk, W., Ford, W., and D. Solo, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL)Profile". [3] IETFProfile", RFC2560 (1999):3280, April 2002. [3] Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams, "X.509 Internet Public Key Infrastructure Online Certificate Status Protocol -OCSP". [4] IETFOCSP", RFC3852 (2004):2560, June 1999. [4] Housley, R., "Cryptographic Message Syntax(CMS)". [5] IETF(CMS)", RFC2634 (1999):3852, July 2004. [5] Hoffman, P., Ed., "Enhanced Security Services forS/MIME". [6] IETFS/MIME", RFC2045 (1996):2634, June 1999. [6] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet MessageBodies". [7] IETFBodies", RFC3161 (2001):2045, November 1996. [7] Adams, C., Cain, P., Pinkas, D., and R. Zuccherato, "Internet X.509 Public Key Infrastructure Time-Stamp Protocol".(TSP)", RFC 3161, August 2001. [8] ITU-T Recommendation X.680 (1997): "Information technology - Abstract Syntax Notation One (ASN.1): Specification of basic notation". [9] ITU-T Recommendation X.501 (2000)/ISO/IEC 9594-1 (2001): "Information technology - Open Systems Interconnection - Directorymodels ".models". [10]IETF RFC 3370 (2002):Housley, R., "Cryptographic Message Syntax (CMS)Algorithms".Algorithms", RFC 3370, August 2002. [11] ITU-T Recommendation F.1: "Operational provisions for the international public telegram service". [12] ITU-T Recommendation X.500: "Information technology - Open Systems Interconnection - The Directory: Overview of concepts, models and services". [13]IETF RFC 3281 (2002):Farrell, S. and R. Housley, "An Internet Attribute Certificate Profile forAuthorization".Authorization", RFC 3281, April 2002. [14] ITU-T Recommendation X.208 (1988): "Specification of Abstract Syntax Notation One (ASN.1)". [15]IETF RFC 5035 (2007). ESSSchaad, J., "Enhanced Security Services (ESS) Update: Adding CertID AlgorithmAgility.Agility", RFC 5035, August 2007. [16] ITU-T Recommendation X.690 (2002): "Information technology ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules(DER) 10.2(DER)". 9.2. Informativereferences ETSI technical specifications can be downloaded free of charge via the Services and Products Download Area at: http://www.etsi.org/WebSite/Standards/StandardsDownload.aspx [EU Directive]References [EUDirective] Directive 1999/93/EC of the European Parliament and of the Council of 13 December 1999 on aCommunitycommunity framework forelectronic signatures.Electronic Signatures. [TS101733] ETSI Standard TS 101 733 V.1.7.3 (2005-06) Electronic Signature Formats. [TS101861] ETSI TS 101 861: "Time stamping profile". [TS101903] ETSI TS 101 903: "XML Advanced Electronic Signatures (XAdES)". [TR102038] ETSI TR 102 038: "Electronic Signatures and Infrastructures (ESI); XML format for signature policies". [TR102272] ETSI TR 102 272 V1.1.1 (2003-12). "Electronic Signatures and Infrastructures (ESI); ASN.1 format for signature policies". [RFC2479]IETF RFC 2479 (1998):Adams, C., "Independent Data Unit Protection Generic Security Service Application Program Interface(IDUP-GSS-API)". [RFC2743] IETF(IDUP- GSS-API)", RFC2743 (2000):2479, December 1998. [RFC2743] Linn, J., "Generic Security Service Application Program Interface Version 2, Update1 [RFC3125] IETF1", RFC3125 (2000):2743, January 2000. [RFC3125] Ross, J., Pinkas, D., and N. Pope, "Electronic SignaturePolicies". [RFC3447] IETFPolicies", RFC3447 (2003): "PKCS3125, September 2001. [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version2.1".2.1", RFC 3447, February 2003. [RFC3494]IETFZeilenga, K., "Lightweight Directory Access Protocol version 2 (LDAPv2) to Historic Status", RFC3494 (2003): "Internet X.509 Public Key Infrastructure Operational Protocols - LDAPv2".3494, March 2003. [RFC3851]IETF RFC 3851 (2004): "SMIMERamsdell, B., Ed., "Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 MessageSpecification". [RFC4210] IETFSpecification", RFC4210 (2005):3851, July 2004. [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, "Internet X.509 Public Key Infrastructure Certificate ManagementProtocols". [RFC4346] IETFProtocol (CMP)", RFC4346 (2006):4210, September 2005. [RFC4346] Dierks, T. and E. Rescorla, "TheTLSTransport Layer Security (TLS) Protocol Version1.1". [RFC4523] IETF1.1", RFC4523 (2006): " Lightweight4346, April 2006. [RFC4523] Zeilenga, K., "Lightweight Directory Access Protocol(LDAP).(LDAP) Schema Definitions for X.509Certificates".Certificates", RFC 4523, June 2006. [ISO7498-2] ISO 7498-2 (1989): "Information processing systems - Open Systems Interconnection - Basic Reference Model - Part 2: Security Architecture". [ISO9796-2] ISO/IEC 9796-2 (2002): "Information technology - Security techniques - Digital signature schemes giving message recovery - Part 2: Integer factorization based mechanisms". [ISO9796-4] ISO/IEC 9796-4 (1998): "Digital signature schemes giving message recovery - Part 4: Discrete logarithm based mechanisms". [ISO10118-1] ISO/IEC 10118-1 (2000): "Information technology - Security techniques - Hash-functions - Part 1: General". [ISO10118-2] ISO/IEC 10118-2 (2000): "Information technology - Security techniques - Hash-functions - Part 2: Hash-functions using an n-bit block cipher algorithm". [ISO10118-3] ISO/IEC 10118-3 (2004): "Information technology - Security techniques - Hash-functions - Part 3: Dedicated hash-functions". [ISO10118-4] ISO/IEC 10118-4 (1998): "Information technology - Security techniques - Hash-functions - Part 4:Hash-functionsHash- functions using modular arithmetic". [ISO10181-5] ISO/IEC 10181-5: Security Frameworks in Open Systems. Non-Repudiation Framework. April 1997. [ISO13888-1] ISO/IEC 13888-1 (2004): "IT security techniques - Non-repudiation - Part 1: General". [ISO14888-1] ISO/IEC 14888-1 (1998): "Information technology - Security techniques - Digital signatures with appendix - Part 1: General". [ISO14888-2] ISO/IEC 14888-2 (1999): "Information technology - Security techniques - Digital signatures with appendix - Part 2: Identity-based mechanisms". [ISO14888-3] ISO/IEC 14888-3 (1998): "Information technology - Security techniques - Digital signatures with appendix - Part 3: Certificate-based mechanisms". [ISO15946-2] ISO/IEC 15946-2 (2002): "Information technology - Security techniques - Cryptographic techniques based on elliptic curves - Part 2: Digital signatures". [CWA14171] CWA 14171 CEN Workshop Agreement: "General Guidelines for Electronic Signature Verification". [XMLDSIG] XMLDSIG: W3C/IETF Recommendation (February 2002): "XML-Signature Syntax and Processing". [X9.30-1] ANSI X9.30-1 (1997): "Public Key Cryptography for the Financial Services Industry - Part 1: The Digital Signature Algorithm (DSA)". [X9.30-2] ANSI X9.30-2 (1997): "Public Key Cryptography for the Financial Services Industry - Part 2: The Secure Hash Algorithm (SHA-1)". [X9.31-1] ANSI X9.31-1 (1997): "Public Key Cryptography Using Reversible Algorithms for the Financial Services Industry - Part 1: The RSA Signature Algorithm". [X9.31-2] ANSI X9.31-2 (1996): "Public Key Cryptography Using Reversible Algorithms for the Financial Services Industry - Part 2: Hash Algorithms". [X9.62] ANSI X9.62(1998): "Public Key Cryptography for the Financial Services Industry - The Elliptic Curve Digital Signature Algorithm (ECDSA)". [P1363] IEEE P1363 (2000): "Standard Specifications for Public-Key Cryptography". 12. Authors' addresses Denis Pinkas Bull S.A.S. Rue Jean-Jaures 78340 Les Clayes sous Bois CEDEX FRANCE EMail: Denis.Pinkas@bull.net Nick Pope Thales eSecurity Meadow View House Long Crendon Aylesbury Buck HP18 9EQ United Kingdom EMail: nick.pope@thales-esecurity.com John Ross Security & Standards Consultancy Ltd(1998): "Public Key Cryptography for the Financial Services Industry - TheWaterhouse Business Centre 2 Cromer Way Chelmsford Essex CM1 2QE United Kingdom EMail: ross@secstan.com 13. Acknowledgments Special thanks to Russ HousleyElliptic Curve Digital Signature Algorithm (ECDSA)". [P1363] IEEE P1363 (2000): "Standard Specifications forreviewingPublic-Key Cryptography". ETSI technical specifications can be downloaded free of charge via thedocument.Services and Products Download Area at: http://www.etsi.org/WebSite/Standards/StandardsDownload.aspx Annex A (normative): ASN.1definitionsDefinitions This annex provides a summary of all the ASN.1 syntax definitions for new syntax defined in the present document.A.1A.1. Signatureformat definitions usingFormat Definitions Using X.208 ASN.1syntaxSyntax NOTE: The ASN.1 module defined insectionAnnex A.1 using syntax defined in ITU-T Recommendation X.208 [14] has precedence over that defined insectionAnnex A.2 in the case of any conflict. ETS-ElectronicSignatureFormats-ExplicitSyntax88 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) eSignature-explicit88(28)} DEFINITIONS EXPLICIT TAGS ::= BEGIN -- EXPORTS All IMPORTS -- Cryptographic Message Syntax (CMS): RFC 3852 ContentInfo, ContentType, id-data, id-signedData, SignedData, EncapsulatedContentInfo, SignerInfo, id-contentType, id-messageDigest, MessageDigest, id-signingTime, SigningTime, id-countersignature, Countersignature FROM CryptographicMessageSyntax2004 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) cms-2004(24) } -- ESS Defined attributes: ESS Update -- RFC 5035 (Adding CertID Algorithm Agility) id-aa-signingCertificate, SigningCertificate, IssuerSerial, id-aa-contentReference, ContentReference, id-aa-contentIdentifier, ContentIdentifier, id-aa-signingCertificateV2 FROM ExtendedSecurityServices-2006 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-ess-2006(30) } -- Internet X.509 Public Key Infrastructure - Certificate and CRL -- Profile: RFC 3280 Certificate, AlgorithmIdentifier, CertificateList, Name, DirectoryString, Attribute, BMPString, UTF8String FROM PKIX1Explicit88 {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-explicit(18)} GeneralNames, GeneralName, PolicyInformation FROM PKIX1Implicit88 {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-implicit (19)} -- Internet Attribute Certificate Profile for Authorization - RFC 3281 AttributeCertificate FROM PKIXAttributeCertificate {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-attribute-cert(12)} -- OCSP - RFC 2560 BasicOCSPResponse, ResponderID FROM OCSP {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-ocsp(14)} -- Time Stamp Protocol RFC 3161 TimeStampToken FROM PKIXTSP {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)} ; -- Definitions of Object Identifier arcs used in the present document -- ================================================================== -- OID used referencing electronic signature mechanisms based on -- the present document for use with theIDUPIndependent Data Unit -- Protection (IDUP) API (seeannexAnnex D) id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::= { itu-t(0) identified-organization(4) etsi(0) electronic-signature-standard (1733) part1 (1) idupMechanism (4) etsiESv1(1) } -- Basic ES CMS Attributes Defined in the present document -- ======================================================= -- OtherSigningCertificate - deprecated id-aa-ets-otherSigCert OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 19 } OtherSigningCertificate ::= SEQUENCE { certs SEQUENCE OF OtherCertID, policies SEQUENCE OF PolicyInformation OPTIONAL -- NOT USED IN THE PRESENT DOCUMENT } OtherCertID ::= SEQUENCE { otherCertHash OtherHash, issuerSerial IssuerSerial OPTIONAL } OtherHash ::= CHOICE { sha1Hash OtherHashValue, -- This contains a SHA-1 hash otherHash OtherHashAlgAndValue} -- Policy ES Attributes Defined in the present document -- ==================================================== -- Mandatory Basic Electronic Signature Attributes as above, -- plus in addition. --Signature Policy IdentifierSignature-policy-identifier attribute id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 15 } SignaturePolicy ::= CHOICE { signaturePolicyId SignaturePolicyId, signaturePolicyImplied SignaturePolicyImplied -- not used in this version } SignaturePolicyId ::= SEQUENCE { sigPolicyId SigPolicyId, sigPolicyHash SigPolicyHash, sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF SigPolicyQualifierInfo OPTIONAL } SignaturePolicyImplied ::= NULL SigPolicyId ::= OBJECT IDENTIFIER SigPolicyHash ::= OtherHashAlgAndValue OtherHashAlgAndValue ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, hashValue OtherHashValue } OtherHashValue ::= OCTET STRING SigPolicyQualifierInfo ::= SEQUENCE { sigPolicyQualifierId SigPolicyQualifierId, sigQualifier ANY DEFINED BY sigPolicyQualifierId } SigPolicyQualifierId ::= OBJECT IDENTIFIER id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 1 } SPuri ::= IA5String id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 2 } SPUserNotice ::= SEQUENCE { noticeRef NoticeReference OPTIONAL, explicitText DisplayText OPTIONAL} NoticeReference ::= SEQUENCE { organization DisplayText, noticeNumbers SEQUENCE OF INTEGER } DisplayText ::= CHOICE { visibleString VisibleString (SIZE (1..200)), bmpString BMPString (SIZE (1..200)), utf8String UTF8String (SIZE (1..200)) } -- Optional Electronic Signature Attributes --Commitment TypeCommitment-type attribute id-aa-ets-commitmentType OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 16} CommitmentTypeIndication ::= SEQUENCE { commitmentTypeId CommitmentTypeIdentifier, commitmentTypeQualifier SEQUENCE SIZE (1..MAX) OF CommitmentTypeQualifier OPTIONAL} CommitmentTypeIdentifier ::= OBJECT IDENTIFIER CommitmentTypeQualifier ::= SEQUENCE { commitmentTypeIdentifier CommitmentTypeIdentifier, qualifier ANY DEFINED BY commitmentTypeIdentifier } id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 1} id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 2} id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 3} id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 4} id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 5} id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 6} --Signer LocationSigner-location attribute id-aa-ets-signerLocation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 17} SignerLocation ::= SEQUENCE { -- at least one of the following shall be present countryName [0] DirectoryString OPTIONAL, -- As used to name a Country in X.500 localityName [1] DirectoryString OPTIONAL, -- As used to name a locality in X.500 postalAdddress [2] PostalAddress OPTIONAL } PostalAddress ::= SEQUENCE SIZE(1..6) OF DirectoryString --Signer AttributesSigner-attributes attribute id-aa-ets-signerAttr OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 18} SignerAttribute ::= SEQUENCE OF CHOICE { claimedAttributes [0] ClaimedAttributes, certifiedAttributes [1] CertifiedAttributes } ClaimedAttributes ::= SEQUENCE OF Attribute CertifiedAttributes ::= AttributeCertificate -- as defined in RFC3281 :3281: seesectionSection 4.1 --Content TimestampContent-time-stamp attribute id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 20} ContentTimestamp ::= TimeStampToken --Signature TimestampSignature-time-stamp attribute id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 14} SignatureTimeStampToken ::= TimeStampToken --Complete Certificate Refs.Complete-certificate-references attribute id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 21} CompleteCertificateRefs ::= SEQUENCE OF OtherCertID --Complete Revocation RefsComplete-revocation-references attribute id-aa-ets-revocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 22} CompleteRevocationRefs ::= SEQUENCE OF CrlOcspRef CrlOcspRef ::= SEQUENCE { crlids [0] CRLListID OPTIONAL, ocspids [1] OcspListID OPTIONAL, otherRev [2] OtherRevRefs OPTIONAL } CRLListID ::= SEQUENCE { crls SEQUENCE OF CrlValidatedID} CrlValidatedID ::= SEQUENCE { crlHash OtherHash, crlIdentifier CrlIdentifier OPTIONAL} CrlIdentifier ::= SEQUENCE { crlissuer Name, crlIssuedTime UTCTime, crlNumber INTEGER OPTIONAL } OcspListID ::= SEQUENCE { ocspResponses SEQUENCE OF OcspResponsesID} OcspResponsesID ::= SEQUENCE { ocspIdentifier OcspIdentifier, ocspRepHash OtherHash OPTIONAL } OcspIdentifier ::= SEQUENCE { ocspResponderID ResponderID, -- As in OCSP response data producedAt GeneralizedTime -- As in OCSP response data } OtherRevRefs ::= SEQUENCE { otherRevRefType OtherRevRefType, otherRevRefs ANY DEFINED BY otherRevRefType } OtherRevRefType ::= OBJECT IDENTIFIER --Certificate ValuesCertificate-values attribute id-aa-ets-certValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 23} CertificateValues ::= SEQUENCE OF Certificate --Certificate Revocation ValuesCertificate-revocation-values attribute id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 24} RevocationValues ::= SEQUENCE { crlVals [0] SEQUENCE OF CertificateList OPTIONAL, ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL, otherRevVals [2] OtherRevVals OPTIONAL} OtherRevVals ::= SEQUENCE { otherRevValType OtherRevValType, otherRevVals ANY DEFINED BY otherRevValType } OtherRevValType ::= OBJECT IDENTIFIER -- CAdES-CTimestamptime-stamp attribute id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 25} ESCTimeStampToken ::= TimeStampToken -- Time-Stamped Certificates and CRLs id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 26} TimestampedCertsCRLs ::= TimeStampToken -- ArchiveTimestamptime-stamp attribute id-aa-ets-archiveTimestampV2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 48} ArchiveTimeStampToken ::= TimeStampToken --Attribute certificate referencesAttribute-certificate-references attribute id-aa-ets-attrCertificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 44} AttributeCertificateRefs ::= SEQUENCE OF OtherCertID --Attribute revocation referencesAttribute-revocation-references attribute id-aa-ets-attrRevocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 45} AttributeRevocationRefs ::= SEQUENCE OF CrlOcspRef ENDA.2A.2. Signatureformat definitions usingFormat Definitions Using X.680 ASN.1syntaxSyntax NOTE: The ASN.1 module defined insectionAnnex A.1 has precedence over that defined insectionAnnex A.2 using syntax defined in ITU-T Recommendation X.680 (1997) [8] in the case of any conflict. ETS-ElectronicSignatureFormats-ExplicitSyntax97 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) eSignature-explicit97(29)} DEFINITIONS EXPLICIT TAGS ::= BEGIN -- EXPORTS All - IMPORTS -- Cryptographic Message Syntax (CMS): RFC 3852 ContentInfo, ContentType, id-data, id-signedData, SignedData, EncapsulatedContentInfo, SignerInfo, id-contentType, id-messageDigest, MessageDigest, id-signingTime, SigningTime, id-countersignature, Countersignature FROM CryptographicMessageSyntax2004 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) cms-2004(24) } -- ESS Defined attributes: ESS Update -- RFC 5035 (Adding CertID Algorithm Agility) id-aa-signingCertificate, SigningCertificate, IssuerSerial, id-aa-contentReference, ContentReference, id-aa-contentIdentifier, ContentIdentifier, id-aa-signingCertificateV2 FROM ExtendedSecurityServices-2006 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) id-mod-ess-2006(30) } -- Internet X.509 Public Key Infrastructure -- Certificate and CRL Profile: RFC 3280 Certificate, AlgorithmIdentifier, CertificateList, Name, Attribute FROM PKIX1Explicit88 {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-explicit(18)} GeneralNames, GeneralName, PolicyInformation FROM PKIX1Implicit88 {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-implicit(19)} -- Internet Attribute Certificate Profile for Authorization - RFC 3281 AttributeCertificate FROM PKIXAttributeCertificate {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-attribute-cert(12)} -- OCSP RFC 2560 BasicOCSPResponse, ResponderID FROM OCSP {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-ocsp(14)} -- RFC 3161 Internet X.509 Public Key Infrastructure -- Time-Stamp Protocol TimeStampToken FROM PKIXTSP {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-tsp(13)} -- X.520 DirectoryString {} FROM SelectedAttributeTypes {joint-iso-itu-t ds(5) module(1) selectedAttributeTypes(5) 4} ; -- Definitions of Object Identifier arcs used in the present document -- ================================================================== -- OID used referencing electronic signature mechanisms based -- on the present document for use with the IDUP API (seeannexAnnex D) id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::= { itu-t(0) identified-organization(4) etsi(0) electronic-signature-standard (1733) part1 (1) idupMechanism (4) etsiESv1(1) } -- Basic ES Attributes Defined in the present document -- =================================================== -- CMS Attributes defined in the present document -- OtherSigningCertificate - deprecated id-aa-ets-otherSigCert OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 19 } OtherSigningCertificate ::= SEQUENCE { certs SEQUENCE OF OtherCertID, policies SEQUENCE OF PolicyInformation OPTIONAL -- NOT USED IN THE PRESENT DOCUMENT } OtherCertID ::= SEQUENCE { otherCertHash OtherHash, issuerSerial IssuerSerial OPTIONAL } OtherHash ::= CHOICE { sha1Hash OtherHashValue, -- This contains a SHA-1 hash otherHash OtherHashAlgAndValue} -- Policy ES Attributes Defined in the present document -- ==================================================== -- Mandatory Basic Electronic Signature Attributes, plus in addition. -- Signature Policy Identifier id-aa-ets-sigPolicyId OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 15 } SignaturePolicy ::= CHOICE { signaturePolicyId SignaturePolicyId, signaturePolicyImplied SignaturePolicyImplied -- not used in this version } SignaturePolicyId ::= SEQUENCE { sigPolicyId SigPolicyId, sigPolicyHash SigPolicyHash, sigPolicyQualifiers SEQUENCE SIZE (1..MAX) OF SigPolicyQualifierInfo OPTIONAL } SignaturePolicyImplied ::= NULL SigPolicyId ::= OBJECT IDENTIFIER SigPolicyHash ::= OtherHashAlgAndValue OtherHashAlgAndValue ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, hashValue OtherHashValue } OtherHashValue ::= OCTET STRING SigPolicyQualifierInfo ::= SEQUENCE { sigPolicyQualifierId SIG-POLICY-QUALIFIER.&id ({SupportedSigPolicyQualifiers}), qualifier SIG-POLICY-QUALIFIER.&Qualifier ({SupportedSigPolicyQualifiers} {@sigPolicyQualifierId})OPTIONAL } SupportedSigPolicyQualifiers SIG-POLICY-QUALIFIER ::= { noticeToUser | pointerToSigPolSpec } SIG-POLICY-QUALIFIER ::= CLASS { &id OBJECT IDENTIFIER UNIQUE, &Qualifier OPTIONAL } WITH SYNTAX { SIG-POLICY-QUALIFIER-ID &id [SIG-QUALIFIER-TYPE &Qualifier] } noticeToUser SIG-POLICY-QUALIFIER ::= { SIG-POLICY-QUALIFIER-ID id-spq-ets-unotice SIG-QUALIFIER-TYPE SPUserNotice } pointerToSigPolSpec SIG-POLICY-QUALIFIER ::= { SIG-POLICY-QUALIFIER-ID id-spq-ets-uri SIG-QUALIFIER-TYPE SPuri } id-spq-ets-uri OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 1 } SPuri ::= IA5String id-spq-ets-unotice OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-spq(5) 2 } SPUserNotice ::= SEQUENCE { noticeRef NoticeReference OPTIONAL, explicitText DisplayText OPTIONAL} NoticeReference ::= SEQUENCE { organization DisplayText, noticeNumbers SEQUENCE OF INTEGER } DisplayText ::= CHOICE { visibleString VisibleString (SIZE (1..200)), bmpString BMPString (SIZE (1..200)), utf8String UTF8String (SIZE (1..200)) } -- Optional Electronic Signature Attributes -- Commitment Type id-aa-ets-commitmentType OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 16} CommitmentTypeIndication ::= SEQUENCE { commitmentTypeId CommitmentTypeIdentifier, commitmentTypeQualifier SEQUENCE SIZE (1..MAX) OF CommitmentTypeQualifier OPTIONAL} CommitmentTypeIdentifier ::= OBJECT IDENTIFIER CommitmentTypeQualifier ::= SEQUENCE { commitmentQualifierId COMMITMENT-QUALIFIER.&id, qualifier COMMITMENT-QUALIFIER.&Qualifier OPTIONAL } COMMITMENT-QUALIFIER ::= CLASS { &id OBJECT IDENTIFIER UNIQUE, &Qualifier OPTIONAL } WITH SYNTAX { COMMITMENT-QUALIFIER-ID &id [COMMITMENT-TYPE &Qualifier] } id-cti-ets-proofOfOrigin OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 1} id-cti-ets-proofOfReceipt OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 2} id-cti-ets-proofOfDelivery OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 3} id-cti-ets-proofOfSender OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 4} id-cti-ets-proofOfApproval OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 5} id-cti-ets-proofOfCreation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) cti(6) 6} -- Signer Location id-aa-ets-signerLocation OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 17} SignerLocation ::= SEQUENCE { -- at least one of the following shall be present countryName [0] DirectoryString{maxSize} OPTIONAL, -- as used to name a Country in X.520 localityName [1] DirectoryString{maxSize} OPTIONAL, -- as used to name a locality in X.520 postalAdddress [2] PostalAddress OPTIONAL } PostalAddress ::= SEQUENCE SIZE(1..6) OF DirectoryString{maxSize} -- maxSize parametrization as specified in X.683 -- Signer Attributes id-aa-ets-signerAttr OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 18} SignerAttribute ::= SEQUENCE OF CHOICE { claimedAttributes [0] ClaimedAttributes, certifiedAttributes [1] CertifiedAttributes } ClaimedAttributes ::= SEQUENCE OF Attribute CertifiedAttributes ::= AttributeCertificate -- as defined in RFC3281 :3281: seesectionSection 4.1 -- Content Timestamp id-aa-ets-contentTimestamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 20} ContentTimestamp ::= TimeStampToken -- Signature Timestamp id-aa-signatureTimeStampToken OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 14} SignatureTimeStampToken ::= TimeStampToken -- Complete Certificate Refs. id-aa-ets-certificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 21} CompleteCertificateRefs ::= SEQUENCE OF OtherCertID -- Complete Revocation Refs id-aa-ets-revocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 22} CompleteRevocationRefs ::= SEQUENCE OF CrlOcspRef CrlOcspRef ::= SEQUENCE { crlids [0] CRLListID OPTIONAL, ocspids [1] OcspListID OPTIONAL, otherRev [2] OtherRevRefs OPTIONAL } CRLListID ::= SEQUENCE { crls SEQUENCE OF CrlValidatedID } CrlValidatedID ::= SEQUENCE { crlHash OtherHash, crlIdentifier CrlIdentifier OPTIONAL } CrlIdentifier ::= SEQUENCE { crlissuer Name, crlIssuedTime UTCTime, crlNumber INTEGER OPTIONAL } OcspListID ::= SEQUENCE { ocspResponses SEQUENCE OF OcspResponsesID } OcspResponsesID ::= SEQUENCE { ocspIdentifier OcspIdentifier, ocspRepHash OtherHash OPTIONAL } OcspIdentifier ::= SEQUENCE { ocspResponderID ResponderID, -- As in OCSP response data producedAt GeneralizedTime -- As in OCSP response data } OtherRevRefs ::= SEQUENCE { otherRevRefType OTHER-REVOCATION-REF.&id, otherRevRefs SEQUENCE OF OTHER-REVOCATION-REF.&Type } OTHER-REVOCATION-REF ::= CLASS { &Type, &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { WITH SYNTAX &Type ID &id } -- Certificate Values id-aa-ets-certValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 23} CertificateValues ::= SEQUENCE OF Certificate -- Certificate Revocation Values id-aa-ets-revocationValues OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 24} RevocationValues ::= SEQUENCE { crlVals [0] SEQUENCE OF CertificateList OPTIONAL, ocspVals [1] SEQUENCE OF BasicOCSPResponse OPTIONAL, otherRevVals [2] OtherRevVals OPTIONAL } OtherRevVals ::= SEQUENCE { otherRevValType OTHER-REVOCATION-VAL.&id, otherRevVals SEQUENCE OF OTHER-REVOCATION-REF.&Type } OTHER-REVOCATION-VAL ::= CLASS { &Type, &id OBJECT IDENTIFIER UNIQUE } WITH SYNTAX { WITH SYNTAX &Type ID &id } -- CAdES-C Timestamp id-aa-ets-escTimeStamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 25} ESCTimeStampToken ::= TimeStampToken -- Time-Stamped Certificates and CRLs id-aa-ets-certCRLTimestamp OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 26} TimestampedCertsCRLs ::= TimeStampToken -- Archive Timestamp id-aa-ets-archiveTimestampV2 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 48} ArchiveTimeStampToken ::= TimeStampToken -- Attribute certificate references id-aa-ets-attrCertificateRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 44} AttributeCertificateRefs ::= SEQUENCE OF OtherCertID -- Attribute revocation references id-aa-ets-attrRevocationRefs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-aa(2) 45} AttributeRevocationRefs ::= SEQUENCE OF CrlOcspRef END Annex B (informative): ExtendedformsForms of Electronic Signatures Section 4 providesonan overview of the various formats of electronic signatures included in the present document. This annex lists the attributes that need to be present in the various extended electronic signature formats andprovideprovides example validation sequences using the extended formats.B.1B.1. ExtendedformsForms ofvalidation dataValidation Data ThecompleteComplete validation data (CAdES-C) described insectionSection 4.3 and illustrated infigureFigure 3 may be extended to createElectronic Signatureselectronic signatures with extended validation data. SomeElectronic Signatureselectronic signature forms that include extended validation are explained below. An X-Long electronic signature (CAdES-X Long) iswhenthe CAdES-C with the values of the certificates and revocationinformation are added to the CAdES-C.information. This form ofElectronic Signatureelectronic signature can be useful when the verifier does not have direct access to the following information: - the signer's certificate; - all the CA certificates that make up the full certification path; - all the associated revocation status information, as referenced in the CAdES-C. In somesituationssituations, additional time-stamps may be created and added to the Electronic Signatures as additional attributes. For example: - time-stamping all the validation data as held with the ES(CAdES- C),(- CAdES-C), this eXtended validation data is called a CAdES-X Type 1; or - time-stamping individual reference data as used for complete validation. This form of eXtended validation data is called an CAdES-X Type 2. NOTE 1: The advantages/drawbacks for CAdES-X Type 1 and CAdES-X Type 2 are discussed insectionAnnex C.4.4. The above time-stamp forms can be useful when it is required to counter the risk that any CA keys used in the certificate chain may be compromised. A combination of the two formats above may be used. This form of eXtended validation data is called an ES X-Long Type 1 or CAdES-X Long Type 2. This form ofElectronic Signatureelectronic signature can be useful when the verifier needs both the values and proof of when the validation data existed. NOTE 2: The advantages/drawbacks for CAdES-X long Type 1 and CAdES-X long Type 2 are discussed insectionAnnex C.4.6.B.1.1B.1.1. CAdES-X Long AnElectronic Signatureelectronic signature with the additional validation data forming the CAdES-X Long form(CAdES-X-Long))(CAdES-X-Long) is illustrated infigureFigure B.1 and comprises the following: - CAdES-BES orCAdES-EPESCAdES-EPES, as defined insectionsSections 4.3 ,5.75.7, or 5.8; - complete-certificate-referencesattributeattribute, as defined insectionSection 6.2.1; - complete-revocation-referencesattributeattribute, as defined insectionSection 6.2.2. The following attributes are required if a TSP is not providing atime- marktime-mark of the ES: - signature-time-stampattributeattribute, as defined insectionSection 6.1.1. The following attributes are required if the full certificate values and revocation values are not already included in the CAdES-BES or CAdES-EPES: - certificate-valuesattributeattribute, as defined insectionSection 6.3.3; - revocation-values attribute, as defined insectionSection 6.3.4. If attributes certificates areusedused, then the following attributes may be present: - attribute-certificate-referencesattributeattribute, defined insectionSection 6.2.3; - attribute-revocation-referencesattributeattribute, as defined insectionSection 6.2.4. Other unsigned attributes may be present, but are not required. NOTE: Attribute certificate and revocation references are only present if a user attribute certificate is present in the electronicsignature,signature; seesectionsSections 6.2.2 and 6.2.3. +---------------------- CAdES-X-Long --------------------------------+ |+-------------------------------------- CAdES-C ---+ | || +----------+ | +-------------+| ||+----- CAdES-BES or CAdES-EPES ----+ |Timestamp | | | || ||| | |over | | | Complete || |||+---------++----------++---------+| |digital | | | certificate || |||| || || || |signature | | | and || ||||Signer's || Signed ||Digital || | | | | revocation || ||||Document ||Attributes||signature|| |Optional | | | data || |||| || || || |when | | | || |||+---------++----------++---------+| |timemarked| | | || ||+----------------------------------+ +----------+ | | || || +-----------+| +-------------+| || |Complete || | || |certificate|| | || |and || | || |revocation || | || |references || | || +-----------+| | |+--------------------------------------------------+ | | | +--------------------------------------------------------------------+ FigureB.1 :B.1: Illustration of CAdES-X-LongB.1.2B.1.2. CAdES-X Type 1 AnElectronic Signatureelectronic signature with the additional validation data forming the eXtendedValidation Datavalidation data - Type 1 X is illustrated infigureFigure B.2 and comprises the following: - the CAdES-BES orCAdES-EPESCAdES-EPES, as defined insectionsSections 4.2,5.75.7, or 5.8; - complete-certificate-referencesattributeattribute, as defined insectionSection 6.2.1; - complete-revocation-referencesattributeattribute, as defined insectionSection 6.2.2; - CAdES-C-Timestamp attribute, as defined insectionSection 6.3.5. The following attributes are required if a TSP is not providing atime- marktime-mark of the ES: - signature-time-stampattributeattribute, as defined insectionSection 6.1.1. If attributes certificates areusedused, then the following attributes may be present: - attribute-certificate-referencesattributeattribute, defined insectionSection 6.2.3; - attribute-revocation-referencesattributeattribute, as defined insectionSection 6.2.4. Other unsigned attributes may be present, but are not required. +------------------------ CAdES-X-Type 1 ----------------------------+ |+---------------------------------- CAdES-C ------+ | || +----------+ | +-------------+ | ||+--- CAdES-BES or CAdES-EPES ------+|Timestamp | | | | | ||| ||over | | | | | |||+---------++----------++---------+||digital | | | | | ||||Signer's || Signed || Digital |||signature | | | Timestamp | | ||||Document ||Attributes||signature||| | | | over | | |||| || || |||Optional | | | CAdES-C | | |||+---------++----------++---------+||when | | | | | ||+----------------------------------+|timemarked| | | | | || +----------+ | | | | || +-----------+| +-------------+ | || |Complete || | || |certificate|| | || | and || | || |revocation || | || |references || | || +-----------+| | |+-------------------------------------------------+ | | | +--------------------------------------------------------------------+ FigureB.2 :B.2: Illustration of CAdES-X Type 1B.1.3B.1.3. CAdES-X Type 2 AnElectronic Signatureelectronic signature with the additional validation data forming the eXtended Validation Data - Type 2 X is illustrated infigure B.3.Figure B.3 and comprises the following: - CAdES-BES orCAdES-EPESCAdES-EPES, as defined insectionsSections 4.2,5.75.7, or 5.8; - complete-certificate-referencesattributeattribute, as defined insectionSection 6.2.1; - complete-revocation-referencesattributeattribute, as defined insectionSection 6.2.2; - time-stamped-certs-crls-referencesattributeattribute, as defined insectionSection 6.3.6. The following attributes are required if a TSP is not providing atime- marktime-mark of the ES: - signature-time-stampattributeattribute, as defined insectionSection 6.1.1. If attributes certificates areusedused, then the following attributes may be present: - attribute-certificate-referencesattributeattribute, defined insectionSection 6.2.3; - attribute-revocation-referencesattributeattribute, as defined insectionSection 6.2.4. Other unsigned attributes may be present, but are not required. +----------------------- CAdES-X-Type 2 -----------------------------+ |+-------------------------------------- CAdES-C --+ | || +----------+ | | ||+-- CAdES-BES or CAdES-EPES -------+|Timestamp | | | ||| ||over | | | |||+---------++----------++---------+||digital | | +-------------+ | |||| || || |||Signature | | | Timestamp | | ||||Signer's || Signed || Digital ||| | | | only over | | ||||Document ||Attributes||signature|||Optional | | | Complete | | |||| || || |||when | | | certificate | | |||+---------++----------++---------+||Timemarked| | | and | | ||+----------------------------------++----------+ | | revocation | | || +-----------+| | references | | || |Complete || +-------------+ | || |certificate|| | || |and || | || |revocation || | || |references || | || +-----------+| | |+-------------------------------------------------+ | | | +--------------------------------------------------------------------+ FigureB.3 :B.3: Illustration of CAdES-X Type 2B.1.4B.1.4. CAdES-X Long Type 1 and CAdES-X Long Type 2 AnElectronic Signatureelectronic signature with the additional validation data forming the CAdES-X Long Type 1 and CAdES-X Long Type 2 is illustrated infigureFigure B.4 and comprises the following: - CAdES-BES orCAdES-EPESCAdES-EPES, as defined insectionsSections 4.3,5.75.7, or 5.8; - complete-certificate-referencesattributeattribute, as defined insectionSection 6.2.1; - complete-revocation-referencesattributeattribute, as defined insectionSection 6.2.2; The following attributes are required if a TSP is not providing atime- marktime-mark of the ES: - signature-time-stampattributeattribute, as defined insectionSection 6.1.1. The following attributes are required if the full certificate values and revocation values are not already included in the CAdES-BES or CAdES-EPES: - certificate-valuesattributeattribute, as defined insectionSection 6.3.3; - revocation-values attribute, as defined insectionSection 6.3.4. If attributes certificates areusedused, then the following attributes may be present: - attribute-certificate-referencesattributeattribute, defined insectionSection 6.2.3; - attribute-revocation-referencesattributeattribute, as defined insectionSection 6.2.4. Plus one of the following attributes is required: - CAdES-C-Timestamp attribute, as defined insectionSection 6.3.5; - time-stamped-certs-crls-referencesattributeattribute, as defined insectionSection 6.3.6. Other unsigned attributes may be present, but are not required. +---------------------- CAdES-X-Type 1 or 2 ------------------------+ | +--------------+| |+-------------------------------------- CAdES-C --+|+------------+|| || +----------+ ||| Timestamp ||| ||+-- CAdES-BES or CAdES-EPES -------+|Timestamp | ||| over ||| ||| ||over | ||| CAdES-C ||| |||+---------++----------++---------+||digital | | +------------+ | |||| || || |||signature | || or || ||||Signer's || Signed || Digital ||| | ||+------------+|| ||||Document ||Attributes||Signature|||Optional | ||| Timestamp ||| |||| || || |||when | ||| only over ||| |||+---------++----------++---------+||timemarked| ||| complete ||| ||+----------------------------------++----------+ ||| certificate||| || ||| and ||| || +-----------+||| revocation ||| || |Complete |||| references ||| || |certificate|||+------------+|| || |and ||+--------------+| || |revocation || +------------+ | || |references || |Complete | | || +-----------+| |certificate | | |+-------------------------------------------------+ | and | | | |revocation | | | | values | | | +------------+ | +-------------------------------------------------------------------+ FigureB.4 :B.4: Illustration of CAdES-X Long Type 1 and CAdES-X Long Type 2B.2 Timestamp extensionsB.2. Time-Stamp Extensions Each instance of the time-stamp attribute mayincludeinclude, as unsigned attributes in the signedData of thetimestamptime-stamp, the followingattributeattributes related to the TSU: - complete-certificate-references attribute of theTSUTSU, as defined insectionSection 6.2.1; - complete-revocation-references attribute of theTSUTSU, as defined insectionSection 6.2.2; - certificate-valuesattribute;attribute of theTSUTSU, as defined insectionSection 6.3.3; - revocation-valuesattribute,attribute of theTSUTSU, as defined insectionSection 6.3.4. Other unsigned attributes may be present, but are not required.B.3B.3. Archivevalidation dataValidation Data (CAdES-A) Before the algorithms,keyskeys, and other cryptographic data used at the time the CAdES-C was built become weak and the cryptographic functions become vulnerable, or the certificates supporting previous time-stampsexpires,expire, the signed data, theCAdES-CCAdES-C, and any additional information(i.e.(i.e., any CAdES-X) should be time-stamped. Ifpossiblepossible, this should use stronger algorithms (or longer key lengths) than in the originaltime- stamp.time-stamp. This additional data and time-stamp is called ArchiveValidation Datavalidation data required for the ES Archive format (CAdES-A). The Time-stamping process may be repeated every time the protection used to time-stamp a previous CAdES-A becomes weak.AnA CAdES-A may thus bear multiple embeddedtime stamps.time-stamps. An example of anElectronic Signatureelectronic signature (ES), with the additional validation data for the CAdES-C and CAdES-X forming the CAdES-A is illustrated infigureFigure B.5. +--------------------------- CAdES-A---------------------------------+ |+----------------------------------------------------+ | || +--------------+| +----------+ | ||+--------------------- CAdES-C ----+|+------------+|| | | | ||| +----------+ ||| Timestamp ||| | | | |||+-- CAdES-BES ------+|Timestamp | ||| over ||| | | | |||| or CAdES-EPES ||over | ||| CAdES-C ||| | Archive | | |||| ||digital | ||+------------+|| | | | |||| ||signature | || or || |Timestamp | | |||| || | ||+------------+|| | | | |||| ||optional | ||| Timestamp ||| | | | |||| ||when | ||| only over ||| | | | |||| ||timemarked| ||| complete ||| | | | |||+-------------------++----------+ ||| certificate||| +----------+ | ||| ||| and ||| | ||| +-------------+||| revocation ||| | ||| | Complete |||| references ||| | ||| | certificate |||+------------+|| | ||| | and ||+--------------+| | ||| | revocation || +------------+ | | ||| | references || |Complete | | | ||| +-------------+| |certificate | | | ||+----------------------------------+ | and | | | || |revocation | | | || | values | | | || +------------+ | | |+----------------------------------------------------+ | +--------------------------------------------------------------------+ FigureB.5 :B.5: Illustration of CAdES-A The CAdES-A comprises the following elements: - the CAdES-BES orCAdES-EPESCAdES-EPES, including their signed and unsigned attributes; - complete-certificate-referencesattributeattribute, as defined insectionSection 6.2.1; - complete-revocation-referencesattributeattribute, as defined insectionSection 6.2.2. The following attributes are required if a TSP is not providing atime- marktime-mark of the ES: - signature-time-stampattributeattribute, as defined insectionSection 6.1.1. If attributes certificates areusedused, then the following attributes may be present: - attribute-certificate-referencesattributeattribute, defined insectionSection 6.2.3; - attribute-revocation-referencesattributeattribute, as defined insectionSection 6.2.4. The following attributes are required if the full certificate values and revocation values are not already included in the CAdES-BES or CAdES-EPES: - certificate-valuesattributeattribute, as defined insectionSection 6.3.3; - revocation-valuesattributeattribute, as defined insectionSection 6.3.4. At least one of the following two attributes is required: - CAdES-C-Timestampattributeattribute, as defined insectionSection 6.3.5; - time-stamped-certs-crls-referencesattributeattribute, as defined insectionSection 6.3.6. The following attribute is required: - archive-time-stampattributesattributes, defined insectionSection 6.4.1. Several instances of the archive-time-stamp attribute may occur with an electronicsignaturesignature, both over time and from different TSUs. Thetime- stamptime-stamp should be created using stronger algorithms (or longer key lengths) than in the original electronic signatures or time-stamps. Other unsigned attributes of the ES may be present, but are not required. Thearchive timestamparchive-time-stamp will itself contain the certificate and revocation information required to validate thearchive timestamp,archive-time-stamp; this may include the following unsigned attributes: - complete-certificate-references attribute of theTSUTSU, as defined insectionSection 6.2.1; - complete-revocation-references attribute of theTSUTSU, as defined insectionSection 6.2.2; - certificate-values attribute of theTSUTSU, as defined insectionSection 6.3.3; - revocation-values attribute of theTSUTSU, as defined insectionSection 6.3.4. Other unsigned attributes may be present, but are not required.B.4B.4. Examplevalidation sequenceValidation Sequence As describedearlierearlier, the signer or initial verifier may collect all the additional data that forms the electronic signature. FigureB.6,B.6 and the subsequentdescription, describesdescription describe how the validation process may build up a complete electronic signature over time. +------------------------------------------ CAdES-C -------------+ |+------------------------------- CAdES-T ------+ | ||+-------------- CAdES ------------+ | | |||+--------------------++---------+|+---------+| +-----------+ | |||| ________ || |||Timestamp|| |Complete | | |||||Sign.Pol| ||Digital |||over || |certificate| | ||||| Id. | Signed ||signature|||digital || | and | | ||||| option.|attributes|| |||signature|| |revocation | | |||||________| |+---------+|+---------+| |references | | |||+--------------------+ | ^ | +-----------+ | ||+---------------------------------+ | | ^ | || 1 | / | | | |+---------------------- | ------------/--------+ | | +----------------------- | ---------- / --------------- / -------+ | /2 ----3-------- +----------+ | / / | | v / | | Signer's | +---------------------+ +-------------+ | document |----->| Validation Process |---->|- Valid | | | +---------------------+ 4 |- Invalid | +----------+ | ^ | ^ |- Validation | v | v | | Incomplete | +---------+ +--------+ +-------------+ |Signature| |Trusted | | Policy | |Service | | Issuer | |Provider| +---------+ +--------+ FigureB.6 :B.6: Illustration of a CAdES validation sequence Soon after receiving theElectronic Signatureelectronic signature (CAdES) from the signer (1), the digital signature value may be checked; the validation process shall at least add a time-stamp (2), unless the signer has provided one which is trusted by the verifier. The validation process may also validate the electronicsignature,signature using additional data(e.g.(e.g., certificates, CRL, etc.) provided bytrusted service providers.Trusted Service Providers. When applicable, the validation process will also need to conform to the requirements specified in a signature policy. If the validation process is validation incomplete, then the output from this stage is the CAdES-T. To ascertain the validity status as Valid or Invalid and communicate that to the user(4)(4), all the additional data required to validate theCAdES-C,CAdES-C must be available(e.g.(e.g., the complete certificate and revocation information). Once the data needed to complete validation data references (CAdES-C) isavailableavailable, then the validation process should: - obtain all the necessary additionalcertificatecertificates and revocation status information; - complete all the validation checks on theES,ES using the complete certificate and revocation information (if a time-stamp is not already present, this may be added at the samestagestage, combining the CAdES-T and CAdES-Cprocess);processes); - record the complete certificate and revocation references (3); - indicate the validity status to the user (4). At the same time as the validation process creates the CAdES-C, the validation process may provide and/or record the values of certificates and revocation status information used inCAdES-C,CAdES-C (5). The end result is calledtheCAdES-XLong (5).Long. This is illustrated infigureFigure B.7. +----------------------------------------------------- CAdES-X Long -+ |+------------------------------- CAdES-C -------------+ | ||+-------------- CAdES ------------+ | | |||+--------------------++---------+|+---------+ |+-----------+| |||| ________ || |||Timestamp| ||Complete || |||||Sign.Pol| ||Digital |||over | ||certificate|| ||||| Id. | Signed ||signature|||digital | || and || ||||| option.|attributes|| |||signature| ||revocation || |||||________| || ||+---------+ || values || |||+--------------------++---------+| ^ +-----------+|+-----------+| ||+---------------------------------+ | |Complete || ^ | || | | |certificate|| | | || | 2 | | and || | | || | | |revocation || | | || | | |references || | | || 1 | / +-----------+| | | |+------------------------ | ------- / --------- ^-----+ / | +------------------------- | ------ / ---------- |--------- / -------+ | / ----- / ------- / +----------+ | / / 3 / 5 | | v | | | | Signer's | +--------------------+ +-----------+ | document |----->| Validation Process |----->| - Valid | | | +--------------------+ 4 | - Invalid | +----------+ | ^ | ^ +-----------+ v | v | +---------+ +--------+ |Signature| |Trusted | | Policy | |Service | | Issuer | |Provider| +---------+ +--------+ FigureB.7 :B.7: Illustration of a CAdES validation sequence with CAdES-X Long When the validation process creates theCAdES-CCAdES-C, it may also create extended forms of validation data. A first alternative is to time-stamp all data forming the CAdES-X Type1 (6).1. This is illustrated infigureFigure B.8. +------------------------------------------------ CAdES-X Type 1 -----+ |+------------------------------- CAdES-C ------------------+ | ||+-------------- CAdES ------------+ | | |||+--------------------++---------+|+---------++----------+|+-------+| |||| ________ || |||Timestamp|| Complete ||| || |||||Sign.Pol| ||Digital |||over || cert. |||Time- || ||||| Id. | Signed ||signature|||digital || and |||stamp || ||||| option.|attributes|| |||signature|| revoc. ||| over || |||||________| |+---------+|+---------+|references|||CAdES-C|| |||+--------------------+ | ^ | ||| || ||+---------------------------------+ | +----------+|+-------+| || | | ^ | ^ | || 1 | / | | | | |+------------------------ | --------- / ----------- / -----+ | | +------------------------- | -------- / ----------- / --------- / ----+ | 2 / ---3---- / +----------+ | / / -----------5------ | | v | | / | Signer's | +--------------------+ +-----------+ | document |----->| Validation Process |-----> | - Valid | | | +--------------------+ 4 | - Invalid | +----------+ | ^ | ^ +-----------+ v | v | +---------+ +--------+ |Signature| |Trusted | | Policy | |Service | | Issuer | |Provider| +---------+ +--------+ FigureB.8 :B.8: Illustration of CAdES with eXtendedValidation Datavalidation data CAdES-X Type 1 Another alternative is to time-stamp the certificate and revocation information references used to validate the electronic signature (but not the signature)(6'); this(6). The end result is called CAdES-X Type 2. This is illustrated infigureFigure B.9. +-------------------------------------------- CAdES-X Type 2 --------+ |+------------------------------- CAdES-C -------------+ | ||+-------------- CAdES ------------+ | | |||+--------------------++---------+|+---------+ |+-----------+| |||| ________ || |||Timestamp| ||Timestamp || |||||Sign.Pol| || |||over | || over || ||||| Id. | Signed ||Digital |||digital | ||complete || ||||| option.|attributes||signature|||signature| ||certificate|| |||||________| || ||| | || || |||+--------------------++---------+|+---------+ || and || ||+---------------------------------+ ^ +-----------+||revocation || || | | |Complete |||references || || | | |certificate||+-----------+| || | | | and || ^ | || 1 | 2 | |revocation || | | || | | |references || | | || | | +-----------+| | | |+------------------------ | --------- | --- ^ --------+ | | | | | 3 | / | | | | / ---------- | | | / / /56 | | | / / / | | | / / / | +------------------------- | ----- | -- | -- / ----------------------+ | | | | v | | | +--------------------+ +-----------+ | Validation Process |----->| - Valid | +--------------------+ 4 | - Invalid | | ^ | ^ +-----------+ v | v | +---------+ +--------+ |Signature| |Trusted | | Policy | |Service | | Issuer | |Provider| +---------+ +--------+ Figure B.9: Illustration of CAdES with eXtendedValidation Datavalidation data CAdES-X Type 2 Before the algorithms used in any of the electronic signatures become or arelikely,likely to be compromised or rendered vulnerable in the future, it may be necessary to time-stamp the entire electronic signature, including all the values of the validation and user data as an ES with ArchiveValidation Datavalidation data (CAdES-A) (7).AnA CAdES-A is illustrated infigureFigure B.10. +----------------------------- CAdES-A ---------------------------+ | | | +-- CAdES-X Long Type 1 or 2 ----------+ | | | | +------------+ | | | | | | | | | | | Archive | | | | | | Time-stamp | | | | | | | | | | | +------------+ | | +---------------------------------------+ ^ | | +----------+ ^ ^ ^ ^ | | | | | | | | | / | | | Signers' | | | | | / | | | Document |\ | | | | / | | | | \ 1 2 | 3 | 5 | 6 | 7 / | | +----------+ \ | | | | / | | \ | | | | / | +----------------- \ --- | - | - | - | ------ / ------------------+ \ | | | | | | | | | | | | | | | | | v v | | | | +-----------------------------+ +-----------+ | Validation Process |----->| - Valid | +-----------------------------+ 4 | - Invalid | | ^ | ^ +-----------+ v | v | +---------+ +--------+ |Signature| |Trusted | | Policy | |Service | | Issuer | |Provider| +---------+ +--------+ Figure B.10: Illustration of CAdES-AB.5B.5. Additionaloptional featuresOptional Features The present document also defines additional optional features to: - indicate a commitment type being made by the signer; - indicate the claimed time when the signature was done; - indicate the claimed location of the signer; - indicate the claimed or certified role under which a signature was created; - support counter signatures; - support multiple signatures. Annex C(informative):General description(informative): General Description This annex explains some of the concepts and provides therationalrationale for normative parts of the present document. The specification below includes a description of why and whentheeach component of an electronic signature is useful, with a brief description of the vulnerabilities and threats and the manner by which they are countered.C.1C.1. Thesignature policySignature Policy The signature policy is a set of rules for the creation and validation of an electronic signature, under which the signature can be determined to be valid. A given legal/contractual context may recognize a particular signature policy as meeting its requirements. A signature policy may be issued, for example, by a party relying on the electronic signatures and selected by the signer for use with that relying party. Alternatively, a signature policy may be established through an electronic trading association for use amongst its members. Both the signer and verifier use the same signature policy. The signature policy may be explicitly identified or may be implied by the semantics of the data being signed and other externaldatadata, like a contract beingreferencedreferenced, which itself refers to a signature policy. An explicit signature policy has a globally unique reference, which is bound to an electronic signature by the signer as part of the signature calculation. The signature policy needs to be available in human readable form so that it can be assessed to meet the requirements of the legal and contractual context in which it is being applied. To facilitate the automatic processing of an electronicsignaturesignature, the parts of the signaturepolicypolicy, whichspecifiesspecify the electronic rules for the creation and validation of the electronicsignaturesignature, alsoneedsneed to be comprehensively defined and in acomputer processablecomputer-processable form. The signature policy thus includes the following: -rules, whichrules that apply to technical validation of a particular signature; - ruleswhichthat may be implied through adoption of Certificate Policies that apply to the electronic signature(e.g.(e.g., rules for ensuring the secrecy of the private signing key); -rules, whichrules that relate to the environment used by the signer,e.g.e.g., the use of an agreed CAD (Card Accepting Device) used in conjunction with a smart card. For example, the major rules required for technical validation can include: - recognized root keys or "top-level certificationauthorities",authorities"; - acceptable certificate policies (ifany),any); - necessary certificate extensions and values (ifany),any); - the need for the revocation status for each component of the certificationtree,tree; - acceptable TSAs (iftime- stamptime-stamp tokens are beingused),used); - acceptable organizations for keeping the audit trails with time-marks (if time-marking is beingused),used); - acceptable AAs (if any are beingused).as well asused),and; - rules defining the components of the electronic signature that shall be provided by the signer with data required by the verifier when required to providelong termlong-term proof.C.2C.2. SignedinformationInformation The information being signed may be defined as a MIME-encapsulated messagewhichthat can be used to signal the format of the content in order to select the right display or application. It can be composed of formatted data, freetexttext, or fields from an electronic form (e-form). For example, the Adobe(tm) format "pdf"may be usedor the eXtensible Mark up Language(XML).(XML) may be used. Annex D defines how the content may be structured to indicate the type of signed data using MIME.C.3C.3. Components of anelectronic signature C.3.1Electronic Signature C.3.1. Reference to thesignature policySignature Policy When two independent parties want to evaluate an electronic signature, it is fundamental that they get the same result. This requirement can be met using comprehensive signature policies that ensure consistency of signature validation. Signature policies can be identified implicitly by the data beingsignedsigned, or they can be explicitly identified using the CAdES-EPES form of electronicsignature,signature; the CAdES-EPES mandates a consistent signature policy must be used by both the signer and verifier. By signing over thesignature policy identifierSignature Policy Identifier in theCAdES-EPESCAdES-EPES, the signer explicitly indicates that he or she has applied the signature policy in creating the signature. In order to unambiguously identify the details of an explicit signature policy that is to be used to verify aCAdES-EPESCAdES-EPES, thesignaturesignature, anidentifieridentifier, and hash of the "Signature policy" shall be part of the signed data. Additional information about the explicit policy(e.g.(e.g., web reference to the document) may be carried as "qualifiers" to thesignature policy identifier.Signature Policy Identifier. In order to unambiguously identify the authority responsible for defining an explicit signaturepolicypolicy, the "Signature policy" can be signed.C.3.2C.3.2. Commitmenttype indicationType Indication The commitment type can be indicated in the electronic signature either: - explicitly using a "commitment type indication" in the electronic signature; - implicitly or explicitly from the semantics of the signed data. If the indicated commitment type is explicit using a "commitment type indication" in the electronic signature, acceptance of a verified signature implies acceptance of the semantics of that commitment type. The semantics of explicit commitmenttypestype indications may be subject to signer and verifier agreement, specified as part of the signature policy or registered for generic use across multiple policies. If a CAdES-EPES electronic signature format is used and the electronic signature includes a commitment type indication other than one of those recognized under the signaturepolicypolicy, the signature shall be treated as invalid. How commitment is indicated using the semantics of the data being signed is outside the scope of the present document. NOTE: Examples of commitment indicated through the semantics of the data beingsigned,signed are: - an explicit commitment made by the signer indicated by the type of data being signed over. Thus, the data structure being signed can have an explicit commitment within the context of the application(e.g.(e.g., EDIFACT purchase order); - an implicit commitmentwhichthat is a commitment made by the signer because the data being signed over has specific semantics(meaning)(meaning), which is only interpretable by humans,(i.e.(i.e., free text).C.3.3C.3.3. CertificateidentifierIdentifier from thesignerSigner In manyreal life environmentsreal-life environments, users will be able to get from different CAs or even from the same CA, different certificates containing the same public key for different names. The prime advantage is that a user can use the same private key for different purposes. Multiple use of the private key is an advantage when a smart card is used to protect the private key, since the storage of a smart card is always limited. When several CAs are involved, each different certificate may contain a different identity,e.g.e.g., as anationalcitizen of a nation or as an employee from a company.ThusThus, when a private key is used for various purposes, the certificate is needed to clarify the context in which the private key was used when generating the signature. Where there is the possibility that multiple private keys are used, it is necessary for the signer to indicate to the verifier the precise certificate to be used. Many current schemes simply add the certificate after the signed data and thus are vulnerable to substitution attacks. If the certificate from the signer was simply appended to the signature and thus not protected by the signature,any oneanyone could substitute one certificateby anotherfor another, and the message would appear to be signed bysome onesomeone else. In order to counter this kind of attack, the identifier of the signer has to be protected by the digital signature from the signer. In order toidentifyunambiguously identify the certificate to be used for the verification of thesignaturesignature, an identifier of the certificate from the signer shall be part of the signed data.C.3.4C.3.4. RoleattributesAttributes While the name of the signer is important, the position of the signer within a company or an organization is of paramount importance as well. Some information(i.e.(i.e., a contract) may only be valid if signed by a user in a particular role,e.g.e.g., a Sales Director. In manycasescases, who the sales Director really is, is not thatimportantimportant, but being sure that the signer is empowered by his company to be the Sales Director is fundamental. The present document defines two different ways for providing this feature: - by placing a claimed role name in the CMS signed attributes field; - by placing an attribute certificate containing a certified role name in the CMS signed attributes field. NOTE: Another possible approach would have been to use additional attributes containing the roles name(s) in the signer's identitycertificatecertificate. However, it was decided not to follow this approach as it significantly complicates the management of certificates. Forexampleexample, by using separate certificates for the signer's identity and roles means new identity keys need not be issued if a user's role changes.C.3.4.1C.3.4.1. ClaimedroleRole The signer may be trusted to state his own role without any certificate to corroborate thisclaim. Inclaim; in whichcasecase, the claimed role can be added to the signature as a signed attribute.C.3.4.2C.3.4.2. CertifiedroleRole Unlike public key certificates that bind an identifier to a public key, Attribute Certificates bind the identifier of a certificate to some attributes, like a role. An Attribute Certificate is NOT issued by a CA but by an Attribute Authority (AA). The AttributeAuthorityAuthority, in mostcasescases, might be under the control of an organization or a company that is best placed to know which attributes are relevant for which individual. The Attribute Authority may use or point to public key certificates issued by any CA, provided that the appropriate trust may be placed in that CA. Attribute Certificates may have various periods of validity. That period may be quite short,e.g.e.g., one day. While this requires that a new Attribute Certificate be obtained every day, valid for that day, this can be advantageous since revocation of such certificates may not be needed. When signing, the signer will have to specify which Attribute Certificate it selects. In order to do so, the Attribute Certificate will have to be included in the signed data in order to be protected by the digital signature from the signer. In order toidentifyunambiguously identify the attribute certificate(s) to be used for the verification of thesignaturesignature, an identifier of the attribute certificate(s) from the signer shall be part of the signed data.C.3.5C.3.5. SignerlocationLocation In sometransactionstransactions, the purported location of the signer at the time he or she applies his signature may need to be indicated. For thisreasonreason, an optional location indicator shall be able to be included. In order to provide indication of the location of the signer at the time he or she applied hissignaturesignature, a location attribute may be included in the signature.C.3.6C.3.6. SigningtimeTime The present document provides the capability to include a claimed signing time as an attribute of an electronic signature. Using thisattributeattribute, a signer may sign over a timewhichthat is the claimed signing time. When an ES with Time-stamp is created(CAdES-T)(CAdES-T), then either a trustedtime stamptime-stamp is obtained and added to the ES or a trustedtime marktime-mark exists in an audit trail. When a verifier accepts a signature, the two times shall be within acceptable limits. A further optional attribute is defined in the present document totimestamptime-stamp thecontent,content and to provide proof of the existence of the content, at the time indicated by the time-stamp token. Using this optionalattributeattribute, a trusted secure time may be obtained before the document is signed and included under the digital signature. This solution requires anon-lineonline connection to a trusted time-stamping service before generating the signature and may not represent the precise signing time, since it can be obtained in advance. However, this optional attribute may be used by the signer to prove that the signed object existed before the date included in the time-stamp (seesectionSection 5.11.4).C.3.7C.3.7. ContentformatFormat When presenting signed data to a humanuseruser, it may be important that there is no ambiguity as to the presentation of the signed information to the relying party. In order for the appropriate representation (text,soundsound, or video) to be selected by the relying party when data (as opposed to datawhichthat has been further signed or encrypted) is encapsulated in the SignedData (indicated by the eContentType within EncapsulatedContentInfo being set to id-data), further typing information should be used to identify the type of document being signed. This is generally achieved using the MIME content typing and encoding mechanism defined in RFC 2045 [6]). Further information on the use of MIME is given in Annex F.C.3.8 Content hintsC.3.8. content-hints Thecontents hintscontents-hints attribute provides information on the innermost signed content of amultilayermulti-layer message where one content is encapsulated in another. This may be useful if the signed data is itself encrypted.C.3.9C.3.9. Contentcross referencingCross-Referencing When presenting a signed data is inrelatedrelation to another signed data, it may be important to identify the signed data to which itrelates to.relates. TheContent-referencecontent-reference andContent-identifier attributescontent-identifier attributes, as defined in ESS (RFC 2634[5])[5]), provide the ability to link a request and reply messages in an exchange between two parties.C.4C.4. Components ofvalidation data C.4.1Validation Data C.4.1. Revocationstatus informationStatus Information A verifier will have to ascertain that the certificate of the signer was valid at the time of the signature. This can be done by either: - using Certificate Revocation Lists (CRLs); - using responses from anon-lineonline certificate status server (forexample;example, obtained through the OCSP protocol). NOTE 1: The time of the signature may not beknow,known, so time-stamping or time-marking may be used to provide the time indication of when it was known that the signature existed. NOTE 2: When validating an electronic signature and checking revocation statusinformationinformation, a "grace period" isrequiredrequired, which needs to be suitably long enough to allow the involved authority to process a"last minute""last-minute" revocation request and for the request to propagate through the revocation system. This grace period is to be added to the time included with thetimestamptime-stamp token or thetime marktime-mark, and thus the revocation status information should be captured after the end of the grace period.C.4.1.1C.4.1.1. CRLinformationInformation When using CRLs to get revocation information, a verifier will have to make sure that he or shegetsgets, at the time of the firstverificationverification, the appropriate certificate revocation information from the signer's CA. This should be done as soon as possible to minimize the time delay between the generation and verification of the signature. However, a "grace period" is required to allow CAs time to process revocation requests. For example, a revocation request may arrive at a CA just before issuing the nextCRLCRL, and there may not enough time to include the revised revocation status information. This involves checking that the signer certificate serial number is not included in the CRL.TheEither the signer, the initial verifier, or a subsequent verifier may obtaineitherthis CRL. If obtained by the signer, then it shall be conveyed to the verifier. It may be convenient to archive the CRL for ease of subsequent verification or arbitration. Alternatively, provided the CRL is archivedelsewhereelsewhere, which is accessible for the purpose of arbitration, then the serial number of the CRL used may be archived together with the verified electronic signature asana CAdES-C form. Even if the certificate serial number appears in the CRL with the status "suspended"(i.e.(i.e., on hold), the signature is not to be deemed as valid since a suspended certificate is not supposed to be used even by its rightful owner.C.4.1.2C.4.1.2. OCSPinformationInformation When using OCSP to get revocation information, a verifier will have to make sure that he or shegetsgets, at the time of the firstverificationverification, an OCSP response that contains the status "valid". This should be done as soon as possible after the generation of the signature, still providing a "grace period" suitable enough to allow the involved authority to process a"last minute""last-minute" revocationrequestrequest. The signer, theverifierverifier, or any other third party may fetch this OCSP response. Since OCSP responses are transient and thus are not archived by anyTSPTSP, including CA, it is the responsibility of every verifier to make sure that it is stored in a safe place. The simplest way is to store them associated with the electronic signature. An alternative would be to store themin some storageso that they can then be easilyretrieved,retrieved and incorporate references to them in the electronic signature itself asana CAdES-C form. In the same way as for the case of the CRL, it may happen that the certificate is declared as invalid but with the secondary status "suspended". In such a case, the same comment as for the CRL applies.C.4.2C.4.2. CertificationpathPath A verifier may have to ascertain that the certification path was valid, at the time of the signature, up to a trustpointpoint, according to the: - naming constraints; - certificate policy constraints; -Signature Policy,signature policy, when applicable. Since the time of the signature cannot be known with certainty, an upper limit of it should be used as indicated by either thetime stamptime-stamp ortime mark.time-mark. In thiscasecase, it will be necessary to capture all the certificates from the certification path, starting with those from the signer and ending up with those of the self-signed certificate from one trustedroot,root; whenapplicableapplicable, this may be specified as part of the Signature Policy. In addition, it will be necessary to capture the Certificate Authority Revocation Lists (CARLs) to provethanthat none of the CAs from the chainwaswere revoked at the time of the signature. Again, all this material may be incorporated in the electronic signature (ES X forms). An alternative would be to storeit in some storagethis information so thatthey canit can be easilyretrieved,retrieved and incorporate references to it in the electronic signature itself as a CAdES-C form.C.4.3 Time-stampingC.4.3. Time-Stamping forlong lifeLong Life ofsignaturesSignatures An important property forlong standinglong-standing signatures is that a signature, having been found once to be valid, shall continue to be so months or years later. A signer,verifierverifier, or both may be required toprovideprovide, on request, proof that a digital signature was created or verified during the validity period oftheall the certificates that make up the certificate path. In this case, the signer,verifierverifier, or both will also be required to provide proof that the signer's certificate and all the CA certificates used to form a valid certification path were not revoked when the signature was created or verified. It would be quiteunacceptable,unacceptable to consider a signature as invalid even if the keys or certificates were later compromised.ThusThus, there is a need to be able to demonstrate that the signature keyswaswere valid at the time that the signature was created to providelong termlong-term evidence of the validity of a signature. It could be the case that a certificate was valid at the time of the signature but revoked some time later. In this event, evidence shall be provided that the document was signed before the signing key was revoked. Time-stamping by a Time-Stamping Authority (TSA) can provide such evidence. Atime stamptime-stamp is obtained by sending the hash value of the given data to the TSA. The returned "time-stamp" is a signed document that contains the hash value, the identity of the TSA, and the time of stamping. This proves that the given data existed before the time of stamping. Time-stamping a digital signature (by sending a hash of the signature to the TSA) before the revocation of the signer's privatekey,key provides evidence that the signaturehashad been created before thekeycertificate was revoked. If a recipient wants to hold a valid electronicsignaturesignature, he will have to ensure that he has obtained a validtime stamptime-stamp forit,it before that key (and any key involved in the validation) is revoked. The sooner the time-stamp is obtained after the signing time, the better. Anytime stamptime-stamp ortime marktime-mark that is taken after the expiration date of any certificate in the certification path has no value in proving the validity of a signature. It is important to note that signatures may be generated "off-line" and time-stamped at a later time by anyone, forexampleexample, by the signer or any recipient interested in the value of the signature. Thetime stamptime-stamp can thus be provided by thesignersigner, together with the signed document, or obtained by the recipient following receipt of the signed document. Thetime stamptime-stamp is NOT a component of the Basic Electronic Signature, but it is the essential component of the ES with Time-stamp. It isrequiredrequired, in the presentdocumentdocument, that if a signer's digital signature value is to be time-stamped, theTime-Stamp Tokentime-stamp token is issued by a trusted source, known as aTime-stampingTime-Stamping Authority. The present document requires that the signer's digital signature valueisbe time-stamped by a trusted source before the electronic signature can become an ES with Complete validation data. Acceptable TSAs may be specified in a Signature Validation Policy. This technique is referred to as CAdES-C in the present document. Should both the signer and verifier be required to time-stamp the signature value to meet the requirements of the signature policy, the signature policy may specify a permitted time delay between the twotime stamps. C.4.4 Time-stampingtime-stamps. C.4.4. Time-Stamping forlong lifeLong Life ofsignatureSignature before CAkey compromises Time-stampedKey Compromises Time-stamped, extended electronic signatures are needed when there is a requirement to safeguard against the possibility of a CA key in the certificate chain ever being compromised. A verifier may be required toprovideprovide, on request, proof that the certification path and the revocation information usedaat the time of the signature were valid, even in the case where one of the issuing keys or OCSP responder keys is later compromised. The present document defines two ways of using time-stamps to protect against this compromise: - time-stamp the ES with Complete validation data, when an OCSP response is used to get the status of the certificate from the signer (CAdES-X Type 1). This format is suitable to be used with an OCSPresponseresponse, and it offers the additional advantageto provideof providing an integrity protection over the whole data; - time-stamp only the certification path and revocation information references when a CRL is used to get the status of the certificate from the signer (CAdES-X Type2). This format is suitable to be used with CRLs, since the time-stamped information may be used for more than one signature (when signers have their certificates issued by the same CA and when signatures can be checked using the same CRLs). NOTE: The signer,verifierverifier, or both may obtain the time-stamp.C.4.4.1 Time-stampingC.4.4.1. Time-Stamping the ES withcomplete validation dataComplete Validation Data (CAdES-X Type 1) When an OCSP response is used, it is necessary totime stamptime-stamp in particular that response in the case the key from the responder would be compromised. Since the information contained in the OCSP response is user specific and time specific, an individualtime stamptime-stamp is needed for every signature received. Instead of placing thetime stamptime-stamp only over the certification path references andtherevocation information references, which include the OCSP response, thetime stamptime-stamp is placed on the CAdES-C. Since the certification path and revocation information references are included in the ES with Complete validationdatadata, they are also protected. For the same cryptographic price, this provides an integrity mechanism over the ES with Complete validation data. Any modification can be immediately detected. It should be noticed that other means of protecting/detecting the integrity of the ES with CompleteValidation Datavalidation data exist and could be used. Although the technique requires atime stamptime-stamp for every signature, it is well suited for individual users wishing to have anintegrity protectedintegrity-protected copy of all the validated signatures they have received. By time-stamping the complete electronic signature, including the digital signature as well as the references to the certificates and revocation status information used to support validation of that signature, the time-stamp ensures that there is no ambiguity in the means of validating that signature. This technique is referred to as CAdES-X Type 1 in the present document. NOTE: Trust is achieved in the references by including a hash of the data being referenced. If it is desired for any reason to keep a copy of the additional data being referenced, the additional data may be attached to the electronic signature, in which case the electronic signature becomesana CAdES-X Long Type11, as defined by the present document.AnA CAdES-X Long Type 1 is simply the concatenation ofana CAdES-X Type11, with a copy of the additional data being referenced.C.4.4.2 Time-stamping certificatesC.4.4.2. Time-Stamping Certificates andrevocation information referencesRevocation Information References (CAdES-X Type 2) Time-stamping each ES with CompleteValidation Datavalidation data, as definedaboveabove, may not be efficient, particularly when the same set of CA certificates and CRL information is used to validate many signatures. Time-stamping CA certificates will stop any attacker from issuing bogus CA certificates that could be claimed to exist before the CA key was compromised. Any bogus time-stamped CA certificates will show that the certificate was created after the legitimate CA key was compromised. In the same way, time-stamping CACRLs,CRLs will stop any attacker from issuing bogus CA CRLswhichthat could be claimed to exist before the CA key was compromised. Time-stamping of commonly used certificates and CRLs can be done centrally,e.g.e.g., inside a company or by a service provider. This method reduces the amount of data the verifier has totime-stamp,time-stamp; forexampleexample, it couldreducebe reduced to just onetime stamptime-stamp per day(i.e.(i.e., in the casewerewhere all the signers use the sameCACA, and the CRL applies for the whole day). The information that needs to betime stampedtime-stamped is not the actual certificates andCRLsCRLs, but the unambiguous references to those certificates and CRLs. This technique is referred to as CAdES-X Type 2 in the present document and requires the following: - all the CA certificates references and revocation information references(i.e.(i.e., CRLs) used in validating the CAdES-C are covered by one or moretime-stamp. Thus antime-stamps. Thus, a CAdES-C with a time-stamp signature value at timeT1,T1 can be proved valid if all the CA and CRL references are time-stamped at time T1+.C.4.5 Time-stampingC.4.5. Time-Stamping forarchiveArchive ofsignatureSignature Advances in computing increase the probability of being able to break algorithms and compromise keys. There is therefore a requirement to be able to protect electronic signatures against this possibility. Over a period oftimetime, weaknesses may occur in the cryptographic algorithms used to create an electronic signature(e.g.(e.g., due to the time available forcrypto analysis,cryptoanalysis, or improvements incrypto analyticalcryptoanalytical techniques). Before such weaknesses become likely, a verifier should take extra measures to maintain the validity of the electronic signature. Several techniques could be used to achieve thisgoalgoal, depending on the nature of the weakened cryptography. In order to simplify matters, a singletechnique,technique called Archive validation data, covering all thecasescases, is being used in the present document. Archive validation data consists of the validation data and the complete certificate and revocation data,time stampedtime-stamped together with the electronic signature. The Archive validation data is necessary if the hash function and the crypto algorithms that were used to create the signature are no longer secure. Also, if it cannot be assumed that the hash function used by theTime StampingTime-Stamping Authority is secure, then nested time-stamps of the Archived Electronic Signature are required. The potential for a Trusted Service Provider (TSP) key compromise should be significantly lower than userkeys,keys because TSP(s) are expected to use stronger cryptography and better key protection. It can be expected that new algorithms (or old ones with greater key lengths) will be used. In such a case, a sequence of time-stamps will protect against forgery. Each time-stamp needs to be affixed before either the compromise of the signing key orofthe cracking of the algorithms used by the TSA. TSAs(Time-stamping(Time-Stamping Authorities) should have long keys(e.g.(e.g., which at the time of drafting the present document was at least 2048 bits for the signing RSA algorithm) and/or a "good" or different algorithm. Nested time-stamps will also protect the verifier against key compromise or cracking the algorithm on the old electronic signatures. The process will need to be performed and iterated before the cryptographic algorithms used for generating the previoustime stamptime-stamp are no longer secure. Archive validation data may thus bear multiple embeddedtime stamps.time-stamps. This technique is referred to as CAdES-A in the present document.C.4.6C.4.6. Reference toadditional dataAdditional Data Using CAdES-X Type 1 or CAdES-X Type 2 extended validationdatadata, verifiers stillneedsneed to keep track of all the components that were used to validate the signature, in order to be able to retrieve them again later on. These components may be archived by an externalsourcesource, like atrusted service provider,Trusted Service Provider; in whichcasecase, referenced information that is provided as part of the ES with Complete validation data (CAdES-C) is adequate. The actual certificates and CRL information reference in the CAdES-C can be gathered when needed for arbitration. If references to additional data are not adequate, then the actual values of all the certificates and revocation information required may be part of the electronic signature. This technique is referred to as CAdES-X Long Type 1 or CAdES-X Long Type 2 in the present document.C.4.7 Time-stampingC.4.7. Time-Stamping formutual recognitionMutual Recognition In some businessscenariosscenarios, both the signer and the verifier need to time-stamp their own copy of the signature value.IdeallyIdeally, the two time-stamps should be as close as possible to each other. EXAMPLE: A contract is signed by twopartiesparties, A andBB, representing their respectiveorganizations,organizations; to time-stamp the signer and verifierdatadata, two approaches are possible: - under the terms of thecontract pre-definedcontract, a predefined common "trusted" TSA may be used; - if both organizations run their own time-stamping services, A and B can have the transaction time-stamped by these two time-stamping services. In the latter case, the electronic signature will only be consideredas valid,valid if both time-stamps were obtained in due time(i.e.(i.e., there should not be a long delay between obtaining the two time-stamps). Thus, neither A nor B can repudiate the signing time indicated by their own time-stamping service. Therefore, A and B do not need to agree on a common "trusted" TSA to get a valid transaction. It is important to note that signatures may be generated "off-line" and time-stamped at a later time by anyone,e.g.e.g., by the signer or any recipient interested in validating the signature. The time-stamp over the signature from the signer can thus be provided by thesignersigner, together with the signed document, and/or be obtained by the verifier following receipt of the signed document. The business scenarios may thus dictate that one or more of thelong- termlong-term signature time-stamping methodsdescribedescribed above be used. This may be part of a mutually agreed Signature Validation Policywhichthat is part of an agreed signature policy under which digitalsignaturesignatures may be used to support the business relationship between the two parties.C.4.8C.4.8. TSAkey compromiseKey Compromise TSA servers should be built in such a way that once the private signature key is installed, there is minimal likelihood of compromise over as long as a possible period.ThusThus, the validity period for the TSA's keys should be as long as possible. Both the CAdES-T and the CAdES-C contain at least onetime stamptime-stamp over the signer's signature. In order to protect against the compromise of the private signature key used to produce that time-stamp, the Archive validation data can be used when a different Time-Stamping Authority key is involved to produce the additional time-stamp. If it is believed that the TSA key used in providing an earlier time-stamp may ever be compromised(e.g.(e.g., outside its validity period), then theCAdES- ACAdES-A should be used. For extremely longperiodsperiods, this may be applied repeatedly using new TSA keys. This technique is referred to as a nested CAdES-A in the present document.C.5C.5. MultiplesignaturesSignatures Some electronic signatures may only be valid if they bear more than one signature. This is generally the casegenerallywhen a contract is signed between two parties. The ordering of the signatures may or may not be important,i.e.i.e., one may or may not need to be applied before the other. Several forms of multiple and counter signatures need to be supported, which fall into two basic categories: - independent signatures; - embedded signatures. Independent signatures are parallel signatures where the ordering of the signatures is not important. The capability to have more than one independent signature over the same data shall be provided. Embedded signatures are applied one after the other and are used where the order in which the signatures are applied is important. The capability to sign over signed data shall be provided. These forms are described insectionSection 5.13. All other multiple signature schemes,e.g.e.g., a signed document with a countersignature, doublecountersignaturescountersignatures, or multiplesignatures,signatures can be reduced to one or moreoccurrenceoccurrences of the above two cases. Annex D (informative): DataprotocolsProtocols tointeroperateInteroperate with TSPsD.1D.1. OperationalprotocolsProtocols The following protocols can be used by signers and verifiers to interoperate with Trusted Service Providers during the electronic signature creation and validation.D.1.1D.1.1. CertificateretrievalRetrieval User certificates, CAcertificatecertificates, and cross-certificates can be retrieved from a repository using the Lightweight Directory Access Protocol as defined inas definedRFC 3494(RFC3494],[RFC3494], with the schema defined in RFC 4523 [RFC4523].D.1.2D.1.2. CRLretrievalRetrieval Certificate revocation lists, including authority revocation lists and partial CRL variants, can be retrieved from a repository using the Lightweight Directory AccessProtocolProtocol, as defined in RFC 3494 [RFC3494], with the schema defined in RFC 4523 [RFC4523].D.1.3 OnLine certificate statusD.1.3. Online Certificate Status As an alternative to the use of certificate revocationlistslists, the status of a certificate can be checked using theOnLineOnline Certificate Status Protocol(OCSP)(OCSP), as defined in RFC 2560 [3].D.1.4 Time-stampingD.1.4. Time-Stamping The time-stamping service can be accessed using the Time-Stamping Protocol defined in RFC 3161 [7].D.2D.2. ManagementprotocolsProtocols Signers and verifiers can use the following management protocols to manage the use of certificates.D.2.1D.2.1. Request forcertificate revocationCertificate Revocation Request for a certificate to be revoked can be made using the revocation request and response messages defined in RFC 4210 [RFC4210]. Annex E (informative): Securityconsiderations E.1Considerations E.1. Protection ofprivate keyPrivate Key The security of the electronic signature mechanism defined in the present document depends on the privacy of the signer's private key. Implementations should take steps to ensure that private keys cannot be compromised.E.2E.2. Choice ofalgorithmsAlgorithms Implementers should be aware that cryptographic algorithms become weaker with time. As new cryptoanalysis techniques are developed and computing performance improves, the work factor to break a particular cryptographic algorithm will reduce. Therefore, cryptographic algorithm implementations should bemodularmodular, allowing new algorithms to be readily inserted. That is, implementers should be prepared for the set ofmandatory to implementmandatory-to-implement algorithms to change over time. Annex F (informative): Examplestructured contentsStructured Contents and MIMEF.1F.1. Use of MIME toencode dataEncode Data The signed content may be structuredasusing MIME (Multipurpose Internet Mail Extensions--- RFC 2045[6].[6]). Whilst the MIME structure was initially developed for Internete-mail,email, it has a number of featureswhichthat make it useful to provide a common structure for encoding a range of electronic documents and other multi-media data(e.g.(e.g., photographs, video). These features include: -it providesproviding a means of signalling the type of "object" being carried(e.g.(e.g., text, image, ZIP file, application data); -it providesproviding a means of associating a file name with an object; -it can associateassociating several independent"objects" (e.g.objects (e.g., a document and image) to form a multi-part object; -it can handlehandling data encoded in text or binary and, if necessary,re-encodere-encoding the binary as text. When encoding a singleobjectobject, MIME consists of: - header information, followed by; - encoded content. This structure can be extended to support multi-part content.F.1.1F.1.1. HeaderinformationInformation A MIME header includes: MIME Version information:e.g.:e.g., MIME-Version: 1.0 Content typeinformationinformation, which includes information describing the content sufficient for it to be presented to a user or applicationprocessprocess, as required. This includes information on the "media type"(e.g.(e.g., text, image, audio) or whether the data is for passing to a particular type of application. In the case oftexttext, the content type includes information on the character set used,e.g.e.g., Content-Type: text/plain;charset="us-ascii" Content encodingcharset="us-ascii". Content-encoding information, which defines how the content isencoded. (Seeencoded (see below about encoding supported by MIME). Other information about thecontentcontent, such as adescription,description or an associated file name. An example MIME header for text object is: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable An example MIME header for a binary file containing a pdf document is: Content-Type: application/pdf Content-Transfer-Encoding: base64 Content-Description: JCFV201.pdf Content-Disposition: filename="JCFV201.pdf"F.1.2F.1.2. ContentencodingEncoding MIME supports a range of mechanisms for encodingtheboth text and binary data. Text data can be carried transparently as lines of text data encoded in77- or8 bit8-bit ASCII characters. MIME also includes a "quoted-printable" encodingwhichthat converts characters other than the basic ASCII into an ASCII sequence. Binary can either be carried: - transparentlya 8 bitas 8-bit octets; or - converted to a basic set of characters using a system called Base64. NOTE: As there are some mail relayswhichthat can only handle7 bit7-bit ASCII, Base64 encoding is usually used on the Internet.F1.3 Multi-part contentF.1.3. Multi-Part Content Several objects(e.g.(e.g., text and a file attachment) can be associated together using a special "multi-part" content type. This is indicated by the content type "multipart" with an indication of the string to be usedindicateindicating a separation between each part. In addition to a header for the overall multipart content, each part includes its own header information indicating the inner content type and encoding. An example of a multipart content is: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="---- =_NextPart_000_01BC4599.98004A80" Content-Transfer-Encoding: 7bit ------=_NextPart_000_01BC4599.98004A80 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Per your request, I've attached our proposal for the Java Card Version 2.0 API and the Java Card FAQ. ------=_NextPart_000_01BC4599.98004A80 Content-Type: application/pdf; name="JCFV201.pdf" Content-Transfer-Encoding: base64 Content-Description: JCFV201.pdf Content-Disposition: attachment; filename="JCFV201.pdf" 0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAAAAAACAAAAAgAAAAA AAAAAEAAAtAAAAAEAAAD+////AAAAAAMAAAAGAAAA////////////////////////////// //////////AANhAAQAYg== ------=_NextPart_000_01BC4599.98004A80-- Multipart content can be nested. So a set of associated objects(e.g.(e.g., HTML text and images) can be handled as a single attachment to another object(e.g.(e.g., text). The Content-Type from each part of the S/MIME message indicates the type of content.F.2F.2. S/MIME The specific use of MIME to carry CMS (extended as defined in the present document) secured data is called S/MIME (see [RFC3851]). S/MIME carries electronic signatures as either: - an "application/pkcs7-mime" object with the CMS carried as a binary attachment (PKCS7 is the name of the early version of CMS). The signed data may be included in the SignedData, which itself may be included in a single S/MIME object. See [RFC3851],section 3.4.2Section 3.4.2: "Signing Using application/pkcs7-mime with SignedData" andfigureFigure F.1 hereafter. or - a "multipart/signed" object with the signed data and the signature encoded as separate MIME objects. The signed data is not included in the SignedData, and the CMS structure only includes the signature. See [RFC3851],section 3.4.3Section 3.4.3: "Signing Using the multipart/signed Format" andfigureFigure F.2 hereafter. +-------------++----------++-------------++------------+ | || || || | | S/MIME || CAdES || MIME || pdf file | | || || || | |Content-Type=||SignedData||Content-Type=||Dear MrSmith| |application/ || eContent ||application/ ||Received | |pkcs7-mime || ||pdf || 100 tins | | || || || | |smime-type= || /| || /| || Mr.Jones | |signed-data || / -----+ / ------+ | | || \ -----+ \ ------+ | | || \| || \| |+------------+ | || |+-------------+ | |+----------+ +-------------+ FigureF.1F.1: Signing Using application/pkcs7-mimeF.2.1F.2.1. Using application/pkcs7-mime This approach is similar to handling signed data as any other binary file attachment. An example of signed data encoded using this approach is: Content-Type: application/pkcs7-mime; smime-type=signed-data; Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=smime.p7m 567GhIGfHfYT6ghyHhHUujpfyF4f8HHGTrfvhJhjH776tbB9HG4VQbnj7 77n8HHGT9HG4VQpfyF467GhIGfHfYT6rfvbnj756tbBghyHhHUujhJhjH HUujhJh4VQpfyF467GhIGfHfYGTrfvbnjT6jH7756tbB9H7n8HHGghyHh 6YT64V0GhIGfHfQbnj75F.2.1F.2.2. Using application/pkcs7-signature CMS also supports an alternative structure where the signature and data being protected are separate MIME objects carried within a single message. In thiscasecase, the signed data is not included in the SignedData, and the CMS structure only includes the signature. See [RFC3851],section 3.4.3Section 3.4.3: "Signing Using the multipart/signed Format" andfigureFigure F.2herafter.hereafter. An example of signed data encoded using this approach is: Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary=boundary42 --boundary42 Content-Type: text/plain This is a clear-signed message. --boundary42 Content-Type: application/pkcs7-signature; name=smime.p7s Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=smime.p7s ghyHhHUujhJhjH77n8HHGTrfvbnj756tbB9HG4VQpfyF467GhIGfHfYT6 4VQpfyF467GhIGfHfYT6jH77n8HHGghyHhHUujhJh756tbB9HGTrfvbnj n8HHGTrfvhJhjH776tbB9HG4VQbnj7567GhIGfHfYT6ghyHhHUujpfyF4 7GhIGfHfYT64VQbnj756 --boundary42-- With this secondapproach MIMEapproach, the signed data passes through the CMS process and is carried as part of amuliple partsmultiple-parts signed MIMEstructurestructure, as illustrated infigureFigure F.2. The CMS structure just holds the electronic signature. +---------------++----------++-------------++------------+ | || || || | | MIME || CAdES || MIME || pdf file | | || || || | |Content-Type= ||SignedData||Content-Type=||Dear MrSmith| |multipart/ || ||application/ ||Received | |signed || ||pdf || 100 tins | | /| || || || | | / -------------------+ /| || Mr.Jones | | \ -------------------+ / -----+ | | \| || || \ -----+ | |Content-Type= || || \| |+------------+ |application/ || |+-------------+ |pdf || | | || | |Content-Type= || | |application/ || | |pkcs7-signature|| | | || | | /| || | | / -------+ | | \ -------+ | | \| ||----------+ | | +---------------+ FigureF.2.F.2: Signing Using application/pkcs7-signature This second approach (multipart/signed) has the advantage that the signed data can be decoded by anyMIME compatibleMIME-compatible system even if it does not recognizeCMS encodedCMS-encoded electronic signatures. Annex G (informative): Relationship to the European Directive and EESSIG.1G.1. Introduction This annex provides an indication of the relationship between electronic signatures created under the present document and requirements under the European Parliament and Council Directive on a Community framework for electronic signatures. NOTE: Legal advice should be sought on the specific national legislation regarding use of electronic signatures. The present document is one of a set of standards being defined under the "European Electronic Signature Standardization Initiative" (EESSI) for electronic signature products and solutions compliant with the European Directive forelectronic signatures. G.2ElectronicsignaturesSignatures. G.2. Electronic Signatures and thedirectiveDirective This directive defines electronic signatures as: - "data in electronic form which are attached to or logically associated with other electronic data and which serve as a method of authentication". The directive states that an electronic signature should not be denied "legal effectiveness and admissibility as evidence in legal proceedings" solely on the grounds that it is in electronic form. The directive identifies an electronic signature as having equivalence to a hand-written signature if it meets specific criteria: - it is an "advanced electronic signature" with the following properties: a) it is uniquely linked to the signatory; b) it is capable of identifying the signatory; c) it is created using means that the signatory can maintain under his sole control; and d) it is linked to the data to which it relates in such a manner that any subsequent change of the data is detectable. - it is based on a certificatewhichthat meets detailed criteria given inannexAnnex Itoof the directive and is issued by a"certification- service-provider" which"certification-service-provider" that meets requirements given inannexAnnex IItoof the directive. Such a certificate is referred to as a "qualified certificate"; - it is created by a"device""device", for which detailed criteria are given inannexAnnex IIItoof the directive. Such a device is referred to a "secure-signature-creationdevice";device". This form of electronic signature is referred to as a "qualified electronic signature" in EESSI (see below).G.3G.3. ETSIelectronic signature formatsElectronic Signature Formats and thedirectiveDirective An electronic signature created in accordance with the present document is: a) considered to be an "electronic signature" under the terms of the Directive; b) considered to be an "advanced electronic signature" under the terms of the Directive; c) considered to be a "Qualified ElectronicSignature"Signature", provided the additional requirements inannexAnnex I,IIII, and III of the Directive are met. The requirements inannexAnnex I,IIII, and III of the Directive are outside the scope of the present document, and are subject to further standardization.G.4G.4. EESSIstandardsStandards andclassesClasses ofelectronic signature G.4.1Electronic Signature G.4.1. Structure of EESSIstandardizationStandardization EESSI looks at standards in several areas. See theETSI ESIETSI, ESI, and CEN web sites for the latest list of standards and theirversionsversions: - use of X.509 public key certificates as qualified certificates; - security Management and Certificate Policy for CSPs Issuing Qualified Certificates; - security requirements for trustworthy systems used by CSPs Issuing Qualified Certificates; - security requirements for Secure Signature Creation Devices; - security requirements for Signature Creation Systems; - procedures for Electronic Signature Verification; - electronic signature syntax and encoding formats; - protocol to interoperate with aTime StampingTime-Stamping Authority; - Policy requirements for Time-Stamping Authorities; and - XML electronic signature formats. Each of these standards addresses a range ofrequirementsrequirements, including the requirements of Qualified ElectronicSignaturesSignatures, as specified inarticleArticle 5.1 of the Directive. However, some of them also address general requirements of electronic signatures for business and electroniccommercecommerce, which all fall into the category ofarticleArticle 5.2 of the Directive. Such variation in the requirements may be identified either as different levels or different options.G.4.2G.4.2. Classes ofelectronic signaturesElectronic Signatures Since some of these standards address a range of requirements, it may be useful to identify a set of standards to address a specific business need. Such a set of standards and their usesdefinesdefine a class of electronic signature. The first class already identified is the qualified electronic signature, fulfilling the requirements ofarticleArticle 5.1 of the Directive. A limited number of "classes of electronic signatures" and corresponding profiles could be defined by EESSI, in closeco-operationcooperation with actors on the market (business, users, suppliers).NeedThe need for such standards is envisaged, in addition to those for qualified electronic signatures, in areas such as: - different classes of electronic signatures withlong termlong-term validity; - electronic signatures for business transactions with limited value.G.4.3G.4.3. EESSIclassesClasses and the ETSIelectronic signature formatElectronic Signature Format The electronic signature format defined in the present document is applicable to the EESSI area "electronic signature and encoding formats". An electronic signature produced by a signer (seesectionSection 5 and conformancesectionSection 10.1) is applicable to the proposed class of electronic signature: "qualified electronic signatures fulfilling article 5.1". With the addition ofvalidation dataattributes by the verifier (seesectionSection 6 and conformancesectionSection 10.2)this would become applicable electronic signatures adding long-term validity attributes tothe qualified electronicsignature.signature supports long-term validity. Annex H(informative):APIs(informative): APIs for thegenerationGeneration andverificationVerification ofelectronic signatures tokensElectronic Signatures Tokens While the present document describes the data format of an electronic signature, the question is whether thereexistsexist APIs (Application Programming Interfaces) able to manipulate these structures. At least two such APIs have beendefined. Onedefined; one set by the IETF and another set by the OMG (Object Management Group).H.1H.1. DataframingFraming In order to be able to use either of these APIs, it will be necessary to frame the previously defined electronic signature data structures using a mechanism-independent token format. Section 3.1 of RFC 2743 [RFC2743]describes that framingspecifies a mechanism-independent level of encapsulating representation for the initial token of a GSS-API context establishment sequence, incorporating an identifier of the mechanism type to be used on that context and enabling tokens to be interpretedunambiguously.unabmiguously. In order to be processable by these APIs, all electronic signature data formats that are defined in the present document shall be framed following that description. The encoding format for the token tag is derived from ASN.1 and DER, but its concrete representation is defined directly in terms of octets rather than at the ASN.1levellevel, in order to facilitate interoperable implementation without use of general ASN.1 processing code. The token tag consists of the following elements, in order: 1) 0x60 -- Tag for RFC 2743 SEQUENCE; indicates that constructed form, definite length encoding follows. 2)Token lengthToken-length octets, specifying length of subsequent data(i.e.(i.e., the summed lengths of elements 3 to 5 in this list, and of the mechanism-defined token object following the tag). This element comprises a variable number of octets: a) If the indicated value is less than 128, it shall be represented in a single octet with bit 8 (high order) set to "0" and the remaining bits representing the value. b) If the indicated value is 128 or more, it shall be represented in two or more octets, with bit 8 of the first octet set to "1" and the remaining bits of the first octet specifying the number of additional octets. The subsequent octets carry the value, 8 bits per octet, with the most significant digit first. The minimum number of octets shall be used to encode the length(i.e.(i.e., no octets representing leading zeros shall be included within the length encoding). 3) 0x06 -- Tag for OBJECT IDENTIFIER. 4) Object identifier length -- length (number of octets) of the encoded object identifier contained in element 5, encoded per rules as described in 2a) and 2b) above. 5) object identifier octets -- variable number of octets, encoded per ASN.1 BER rules: - The first octet contains the sum of two values: (1) the top-level object identifier component, multiplied by 40 (decimal); and (2) the second-level object identifier component. This special case is the only point within an object identifier encoding where a single octet represents contents of more than one component. - Subsequent octets, if required, encodesuccessively-lowersuccessively lower components in the represented object identifier. A component's encoding may span multiple octets, encoding 7 bits per octet (most significant bits first) and with bit 8 set to "1" on all but the final octet in the component's encoding. The minimum number of octets shall be used to encode each component(i.e.(i.e., no octets representing leading zeros shall be included within a component's encoding). NOTE: In many implementations, elements 3 to 5 may be stored and referenced as a contiguous string constant. The token tag is immediately followed by a mechanism-defined token object. Note that no independent size specifier intervenes following the object identifier value to indicate the size of themechanism- definedmechanism-defined token object. Tokens conforming to the present document shall have the following OID in order to be processable by IDUP-APIs: id-etsi-es-IDUP-Mechanism-v1 OBJECT IDENTIFIER ::= { itu-t(0) identified-organization(4) etsi(0) electronic-signature-standard (1733) part1 (1) IDUPMechanism (4) etsiESv1(1) }H.2H.2. IDUP-GSS-APIsdefinedDefined by the IETF The IETF CAT WGhas producedproduced, in December19981998, an RFC (RFC 2479 [RFC2479]) under the name of IDUP-GSS-API (Independent Data Unit Protection) able to handle the electronic signature data format defined in the present document. The IDUP-GSS-API includes support for non-repudiation services. It supports evidence generation, where "evidence" is information that either by itself, or when used in conjunction with other information, is used to establish proof about an event or action, as wellaas evidence verification. IDUP supports various types of evidences. All the types defined in IDUP are supported in the present document through thecommitment typecommitment-type parameter. Section 2.3.3 of IDUP describes the specific calls needed to handleevidencesevidence ("EV" calls). The "EV" group of calls provides a simple, high-level interface to underlying IDUP mechanisms when application developers need to dealonlywithevidences butonly evidence: not with encryption or integrity services. All generations and verification are performed according to the content of a NR policy that is referenced in the context. Get_token_details is used to returnto an applicationthe attributes that correspond to a given inputtoken.token to an application. SinceIDUP-GSS- APIIDUP-GSS-API tokens are meant to be opaque to the calling application, this function allows the application to determine information about the token without having to violate the opaqueness intention of IDUP. Of primary importance is the mechanism type, which the application can then use as input to the IDUP_Establish_Env() call in order to establish the correct environment in which to have the token processed. Generate_token generates a non-repudiation token using the current environment. Verify_evidence verifies the evidence token using the current environment. This operation returns a major_status codewhichthat can be used to determine whether the evidence contained in a token is complete(i.e.(i.e., can be successfully verified (perhaps years) later). If a token's evidence is not complete, the token can be passed to anotherAPI: form_complete_piduAPI, form_complete_pidu, to complete it. This happens when a status "conditionally valid" is returned. That status corresponds to the status "validation incomplete" of the present document. Form_complete_PIDU is used primarily when the evidence token itself does not contain all the data required for itsverificationverification, and it is anticipated that some of the data not stored in the token may become unavailable during the interval between generation of the evidence token and verification unless it is stored in the token. The Form_Complete_PIDU operation gathers the missing information and includes it in the token so that verification can be guaranteed to be possible at any future time.H.3H.3. CORBAsecurity interfaces definedSecurity Interfaces Defined by the OMG Non-repudiation interfaces have been defined in "CORBA Security", a document produced by the OMG (Object Management Group). These interfaces are described in IDL (Interface Definition Language) and are optional. The handling of "tokens" supporting non-repudiation is done through the following interfaces: - set_NR_features specifies the features to apply to future evidence generation and verification operations; - get_NR_features returns the featureswhichthat will be applied to future evidence generation and verification operations; - generate_token generates aNon-repudiationnon-repudiation token using the currentNon-repudiationnon-repudiation features; - verify_evidence verifies the evidence token using the currentNon-repudiationnon-repudiation features; - get_tokens_details returns information about an inputNon- repudiationnon-repudiation token. The information returned depends upon the type of token; - form_complete_evidence is used when the evidence token itself does not contain all the data required for its verification, and it is anticipated that some of the data not stored in the token may become unavailable during the interval between generation of the evidence token and verification unless it is stored in the token. The form_complete_evidence operation gathers the missing information and includes it in the token so that verification can be guaranteed to be possible at any future time. NOTE: The similarity between the two sets of APIs is noticeable. Annex I(informative):Cryptographic algorithms(informative): Cryptographic Algorithms RFC 3370 [10] describes the conventions for using several cryptographic algorithms with the Crytographic Message Syntax (CMS). Only the hashing and signing algorithms are appropriate for use with the present document. Since the publication of RFC 3370 [10], MD5 has been broken. This algorithm is nomorelonger consideredasappropriate and has been deleted from the list of algorithms.I.1I.1. Digestalgorithms I.1.1Algorithms I.1.1. SHA-1 The SHA-1 digest algorithm is defined in FIPS Pub 180-1. The algorithm identifier for SHA-1 is: sha-1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } The AlgorithmIdentifier parameters field is optional. If present, the parameters field shall contain an ASN.1 NULL. Implementations should accept SHA-1 AlgorithmIdentifiers with absent parameters as well as NULL parameters. Implementations should generate SHA-1 AlgorithmIdentifiers with NULL parameters.I.1.2I.1.2. General The following is a selection of work that has been done in the area of digest algorithms or, as they are often called, hash functions: - ISO/IEC 10118-1 (1994) [ISO10118-1]: "Information technology - Security techniques - Hash-functions - Part 1: General". ISO/IEC 10118-1 contains definitions and describes basic concepts. - ISO/IEC 10118-2 (1994) [ISO10118-2]: "Information technology - Security techniques - Hash-functions - Part 2: Hash-functions using an n-bit block cipher algorithm". ISO/IEC 10118-2 specifies two ways to construct a hash-function from a block cipher. - ISO/IEC 10118-3 (1997) [ISO10118-3]: "Information technology - Security techniques - Hash-functions - Part 3: Dedicated hash-functions". ISO/IEC 10118-3 specifies the following dedicated hash-functions: - SHA-1 (FIPS 180-1); - RIPEMD-128; - RIPEMD-160. - ISO/IEC 10118-4 (1998) [ISO10118-4]: "Information technology - Security techniques - Hash-functions - Part 4: Hash-functions using modular arithmetic". - RFC 1320 (PS 1992): "The MD4 Message-Digest Algorithm". RFC 1320 specifies the hash-function MD4. Today, MD4 is consideredout- dated.outdated. - RFC 1321 (I 1992): "The MD5 Message-Digest Algorithm". RFC 1321 (informational) specifies thehash-unctionhash-function MD5. Today, MD5 is not recommended for new implementations. - FIPS Publication 180-1 (1995): "Secure Hash Standard". FIPS 180-1 specifies the Secure Hash Algorithm (SHA), dedicated hash- function developed for use with the DSA. The originalSHASHA, published in19931993, was slightly revised in 1995 and renamed SHA-1. - ANSI X9.30-2 (1997) [X9.30-2]: "Public Key Cryptography for the Financial Services Industry - Part 2: The Secure Hash Algorithm (SHA-1)". X9.30-2 specifies the ANSI-Version of SHA-1. - ANSI X9.31-2 (1996) [X9.31-2]: "Public Key Cryptography Using Reversible Algorithms for the Financial Services Industry - Part 2: Hash Algorithms". X9.31-2 specifies hash algorithms.I.2I.2. Digitalsignature algorithms I.2.1Signature Algorithms I.2.1. DSA The DSA signature algorithm is defined in FIPS Pub 186. DSA is always used with the SHA-1 message digest algorithm. The algorithm identifier for DSA is: id-dsa-with-sha1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) x9-57 (10040) x9cm(4) 3 } The AlgorithmIdentifier parameters field shall not be present.I.2.2I.2.2. RSA The RSA signature algorithm is defined in RFC 3447 [RFC3447]. RFC 3370 [10] specifies the use of the RSA signature algorithm with the SHA-1 algorithm. The algorithm identifier for RSA with SHA-1 is: Sha1WithRSAEncryption OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-1(1) 5 } NOTE: RFC 3370 [10] recommends that MD5isnot be used for new implementations.I.2.3I.2.3. General The following is a selection of work that has been done in the area of digital signature mechanisms: - FIPS Publication 186 (1994): "Digital Signature Standard". NIST's Digital Signature Algorithm (DSA) is a variant of ElGamal's DiscreteLogarithm basedLogarithm-based digital signature mechanism. The DSA requires a 160-bit hash-function and mandates SHA-1. - IEEE P1363 (2000) [P1363]: "Standard Specifications forPublic-KeyPublic- Key Cryptography". IEEE P1363 contains mechanisms for digital signatures, key establishment, and encipherment based on three families ofpublic-keypublic key schemes: - "Conventional" Discrete Logarithm(DL) based(DL)-based techniques,i.e.i.e., Diffie-Hellman (DH) key agreement, Menezes-Qu-Vanstone (MQV) key agreement, the Digital Signature Algorithm (DSA), and Nyberg-Rueppel (NR) digital signatures; - Elliptic Curve(EC) based(EC)-based variants of the DL-mechanisms specified above,i.e.i.e., EC-DH, EC-MQV, EC-DSA, and EC-NR. For elliptic curves, implementation options include mod p and characteristic 2 with polynomial or normal basis representation; - Integer Factoring(IF) based techniques(IF)-based techniques, including RSA encryption, RSA digital signatures, and RSA-based key transport. - ISO/IEC 9796-2 (1997) [ISO9796-2]: "Information technology - Security techniques - Digital signature schemes giving message recovery - Part 2: Mechanisms using a hash-function". ISO/IEC 9796-2 specifies digital signature mechanisms with partial message recovery that are also based on the RSA technique but make use of a hash-function. - ISO/IEC 9796-4 (1998) [ISO9796-4]: "Digital signature schemes giving message recovery - Part 4: Discrete logarithm based mechanisms". ISO/IEC 9796-4 specifies digital signature mechanisms with partial message recovery that are based on Discrete Logarithm techniques. The document includes the Nyberg-Rueppel scheme. - ISO/IEC 14888-1 [ISO14888-1]: "Digital signatures with appendix - Part 1: General". ISO/IEC 14888-1 contains definitions and describes the basic concepts of digital signatures with appendix. - ISO/IEC 14888-2 [ISO14888-2]: "Digital signatures with appendix - Part 2: Identity-based mechanisms". ISO/IEC 14888-2 specifies digital signature schemes with appendix that make use of identity-based keying material. The document includes the zero-knowledge techniques of Fiat-Shamir and Guillou-Quisquater. - ISO/IEC 14888-3 [ISO14888-3]: "Digital signatures with appendix - Part 3: Certificate-based mechanisms". ISO/IEC 14888-3 specifies digital signature schemes with appendix that make use of certificate-based keying material. The document includes five schemes: - DSA; - EC-DSA, an ellipticcurve basedcurve-based analog of NIST's Digital Signature Algorithm; - Pointcheval-Vaudeney signatures; - RSA signatures; - ESIGN. - ISO/IEC 15946-2 (2002) [ISO15946-2]: "Cryptographic techniques based on elliptic curves - Part 2: Digital signatures", specifies digital signature schemes with appendix using elliptic curves. - The document includes two schemes: - EC-DSA, an ellipticcurve basedcurve-based analog of NIST's Digital Signature Algorithm; - EC-AMV, an ellipticcurve basedcurve-based analog of the Agnew-Muller- Vanstone signature algorithm. - ANSI X9.31-1 (1997) [X9.31-1]: "Public Key Cryptography Using Reversible Algorithms for the Financial Services Industry - Part 1: The RSA Signature Algorithm". ANSI X9.31-1 specifies a digital signature mechanism with appendix using the RSApublic-keypublic key technique. - ANSI X9.30-1 (1997) [X9.30-1]: "Public Key Cryptography Using Irreversible Algorithms for the Financial Services Industry - Part 1: The Digital Signature Algorithm (DSA)". ANSI X9.30-1 specifies the DSA, NIST's Digital Signature Algorithm. - ANSI X9.62 (1998) [X9.62]: "Public Key Cryptography for the Financial Services Industry - The Elliptic Curve Digital Signature Algorithm (ECDSA)". ANSI X9.62 specifies the Elliptic Curve Digital Signature Algorithm, an analog of NIST's Digital Signature Algorithm (DSA) using elliptic curves. The appendices provide tutorial information on the underlying mathematics for elliptic curve cryptography and give many examples. Annex J (informative): Guidance onnaming J.1Naming J.1. Allocation ofnamesNames The subject name shall be allocated through a registration scheme administered through a Registration Authority (RA) to ensure uniqueness. This RA may be an independent body or a function carried out by the Certification Authority. In addition to ensuring uniqueness, the RA shall verify that the name allocated properly identifies the applicant and that authentication checks are carried out to protect against masquerade. The name allocated by an RA is based on registration information provided by, or relating to, the applicant(e.g.(e.g., his personal name, date of birth, residence address) and information allocated by the RA. Three variations commonly exist: - the name is based entirely on registrationinformationinformation, which uniquely identifies the applicant(e.g.(e.g., "Pierre Durand (born on) July 6, 1956"); - the name is based on registrationinformationinformation, with the addition of qualifiers added by the registration authority to ensure uniqueness(e.g.(e.g., "Pierre Durand 12"); - the registration information is kept private by the registration authority and the registration authority allocates a "pseudonym".J.2J.2. ProvidingaccessAccess toregistration informationRegistration Information Under certaincircumstancescircumstances, it may be necessary for information used during registration, but not published in the certificate, to be made available to third parties(e.g.(e.g., to an arbitrator to resolve a dispute or for law enforcement). This registration information is likely to include personal and sensitive information.ThusThus, the RA needs to establish a policy for: - whether the registration information should be disclosed; - to whom such information should be disclosed; - under what circumstances such information should be disclosed. This policy may be different whether the RA is being used only within a company or for public use. The policy will have to take into account national legislation and in particular any data protection and privacy legislation. Currently, the provision of access to registration is a local matter for the RA. However, if open access is required, standardprotocolsprotocols, such as HTTP--- RFC 2068 (Internet Web AccessProtocol)Protocol), may be employed with the addition of security mechanisms necessary to meet the data protection requirements(e.g.(e.g., Transport Layer Security--- RFC 4346[RFC4346][RFC4346]) with clientauthentication). J.3authentication. J.3. Namingschemes J.3.1Schemes J.3.1. NamingschemesSchemes forindividual citizensIndividual Citizens In somecasescases, the subject name that is contained in a public key certificate may not be meaningful enough. This may happen because of the existence of homonyms or because of the use of pseudonyms. A distinction could be made if more attributes were present. However, adding more attributes to a public key certificate placed in a public repository would be going against the privacy protection requirements. In anycasecase, the Registration Authority will get information at the time ofregistrationregistration, but not all that information will be placed in the certificate. In order to achieve a balance between these two oppositerequirementsrequirements, the hash values of some additional attributes can be placed in a public key certificate. When the certificate owner provides these additional attributes, then they can be verified. Using biometrics attributes may unambiguously identify a person.ExampleExamples of biometrics attributes that can be used include: a picture or a manual signature from the certificate owner. NOTE: Using hash values protects privacy only if the possible inputs are large enough. For example, using the hash of a person's social security number is generally not sufficient since it can easily be reversed. A picture can be used if the verifier once met the person and later on wants to verify that the certificate that he or she got relates to the person whom was met. In such a case, at the firstexchangeexchange, the picture issentsent, and the hash contained in the certificate may be used by the verifier to verify that it is the right person. At the nextexchangeexchange, the picture does not need to be sent again. A manual signature may be used if a signed document has been received beforehand. In such a case, at the firstexchangeexchange, the drawing of the manual signature issentsent, and the hash contained in the certificate may be used by the verifier to verify that it is the right manual signature. At the nextexchangeexchange, the manual signature does not need to be sent again.J.3.2J.3.2. NamingschemesSchemes foremployeesEmployees of anorganizationOrganization The name of an employee within an organization is likely to be some combination of the name of the organization and the identifier of the employee within that organization. An organization name is usually a registered name,i.e.i.e., business or trading name used inday to dayday-to-day business. This name is registered by a Naming Authority, which guarantees that the organization's registered name is unambiguous and cannot be confused with another organization. In order to get more information about a given registered organization name, it is necessary to go back to a publicly available directory maintained by the Naming Authority. The identifier may be a name or a pseudonym(e.g.(e.g., a nickname oraan employee number). When it is a name, it is supposed to be descriptive enough to unambiguously identify the person. When it is a pseudonym, the certificate does not disclose the identity of the person.HoweverHowever, it ensures that the person has been correctly authenticated at the time of registration and therefore may be eligible to some advantages implicitly or explicitly obtained through the possession of the certificate. In either case, however, this can be insufficient because of the existence of homonyms. Placing more attributes in the certificate may be one solution, forexampleexample, by giving the organization unit of the person or the name of a city where the office is located.HoweverHowever, the more information is placed in thecertificatecertificate, the more problems arise if there is a change in the organization structure or the place of work. So this may not be the best solution. An alternative is to provide more attributes (like the organization unit and the place of work) through access to a directory maintained by the company. It is likelythatthat, at the time ofregistrationregistration, the Registration Authority got more information than what was placed in the certificate, if such additional information is placed in a repository accessible only to the organization.Annex K (informative): Changes from the previous version The title of the document has changed to be aligned with the title of XAdES (XML Advanced Electronic Signatures), the vocabulary used within the present document has been aligned with the vocabulary used in XAdES, If the hash of the signature policy is unknown, then, by convention, the sigPolicyHash shall be setAcknowledgments Special thanks toall zeros. The OIDs from the ASN.1 modules have changedRuss Housley for reviewing thefollowing reasons: - the OIDs of the ASN.1 modules of RFC 2560 and RFC 3161 have been included. - since RFC 2459 and RFC 3852 has been obsoleted by RFC 3280 and RFC 3852 respectively, there was the need to refer to the OIDs of the ASN.1 modules of RFC 3280 and RFC 3852, instead of the OIDs of the ASN.1 modules of RFC 2459 and RFC 3852. - other changes are related to the addition of the signing- certificate attribute, where the ESS signing-certificate attribute defined in RFC 2634 [5], shall be used if the SHA-1 hashing algorithm is used, while the ESS signing-certificate attribute v2, defined in "ESS Update: Adding CertID Algorithm Agility RFC 5035 [15] shall be used when other hashing algorithms are to be used. - the definition of the Archive time-stamp attribute has been changed in section 6.4.1. to protect all signed and unsined attributes. A new object identifier has been assigned to this attribute.document. Authors' Addresses Denis Pinkas Bull SAS Rue Jean-Jaures 78340 Les Clayes sous Bois CEDEX FRANCE EMail: Denis.Pinkas@bull.net Nick Pope Thales eSecurity Meadow View House Long Crendon Aylesbury Buck HP18 9EQ United Kingdom EMail: nick.pope@thales-esecurity.com John Ross Security & Standards Consultancy Ltd The Waterhouse Business Centre 2 Cromer Way Chelmsford Essex CM1 2QE United Kingdom EMail: ross@secstan.com Full Copyright Statement Copyright (C) The IETF Trust(2007).(2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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