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RFC 3126

 
 
 

Electronic Signature Formats for long term electronic signatures

Part 3 of 3, p. 49 to 84
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Annex A (normative): ASN.1 Definitions

   This annex provides a summary of all the ASN.1 syntax definitions for
   new syntax defined in this document.

A.1  Definitions Using X.208 (1988) ASN.1 Syntax

   NOTE:  The ASN.1 module defined in clause A.1 has precedence over
   that defined in Annex A-2 in the case of any conflict.

      ETS-ElectronicSignatureFormats-88syntax { iso(1) member-body(2)
      us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 5}

DEFINITIONS EXPLICIT TAGS ::=

BEGIN

-- EXPORTS All -

IMPORTS

-- Crypographic Message Syntax (CMS): RFC 2630

  ContentInfo, ContentType, id-data, id-signedData, SignedData,
  EncapsulatedContentInfo, SignerInfo, id-contentType,
  id-messageDigest, MessageDigest, id-signingTime, SigningTime,
  id-countersignature, Countersignature

  FROM CryptographicMessageSyntax
    { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
      smime(16) modules(0) cms(1) }

-- ESS Defined attributes: RFC 2634
-- (Enhanced Security Services for S/MIME)

  id-aa-signingCertificate, SigningCertificate, IssuerSerial,
  id-aa-contentReference, ContentReference,
  id-aa-contentIdentifier, ContentIdentifier

  FROM ExtendedSecurityServices
     { iso(1) member-body(2) us(840) rsadsi(113549)
       pkcs(1) pkcs-9(9) smime(16) modules(0) ess(2) }

-- Internet X.509 Public Key Infrastructure
-- Certificate and CRL Profile: RFC 2459

  Certificate, AlgorithmIdentifier, CertificateList, Name,
  GeneralNames, GeneralName, DirectoryString,Attribute,

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  AttributeTypeAndValue, AttributeType, AttributeValue,
  PolicyInformation, 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-
   88(1)}

-- X.509 '97 Authentication Framework

AttributeCertificate

  FROM AuthenticationFramework
  {joint-iso-ccitt ds(5) module(1) authenticationFramework(7) 3}

-- The imported AttributeCertificate is defined using the X.680 1997
-- ASN.1 Syntax,
-- an equivalent using the 88 ASN.1 syntax may be used.


-- OCSP 2560

BasicOCSPResponse, ResponderID

  FROM OCSP {-- OID not assigned -- }

-- Time Stamp Protocol Work in Progress

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)}

-- S/MIME Object Identifier arcs used in this document
-- ===================================================

-- S/MIME  OID arc used in this document
-- id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
--             us(840) rsadsi(113549) pkcs(1) pkcs-9(9) 16 }

-- S/MIME Arcs
-- id-mod  OBJECT IDENTIFIER ::= { id-smime 0 }
-- modules
-- id-ct   OBJECT IDENTIFIER ::= { id-smime 1 }
-- content types
-- id-aa   OBJECT IDENTIFIER ::= { id-smime 2 }
-- attributes

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-- id-spq  OBJECT IDENTIFIER ::= { id-smime 5 }
-- signature policy qualifier
-- id-cti  OBJECT IDENTIFIER ::= { id-smime 6 }
-- commitment type identifier

-- Definitions of Object Identifier arcs used in this document
-- ===========================================================

-- The allocation of OIDs to specific objects are given below with the
-- associated ASN.1 syntax definition

-- OID used referencing electronic signature mechanisms based on this
-- standard for use with the IDUP API (see annex 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) }

-- CMS Attributes Defined in this document
-- =======================================

-- Mandatory Electronic Signature Attributes

-- OtherSigningCertificate

    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 THIS DOCUMENT
}

OtherCertID ::= SEQUENCE {
     otherCertHash            OtherHash,
     issuerSerial             IssuerSerial OPTIONAL
}

OtherHash ::= CHOICE {
    sha1Hash     OtherHashValue,  -- This contains a SHA-1 hash
    otherHash    OtherHashAlgAndValue
}

OtherHashValue ::= OCTET STRING

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OtherHashAlgAndValue ::= SEQUENCE {
  hashAlgorithm    AlgorithmIdentifier,
  hashValue        OtherHashValue
}

-- 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
}

SignaturePolicyId ::= SEQUENCE {
        sigPolicyIdentifier   SigPolicyId,
        sigPolicyHash         SigPolicyHash,
        sigPolicyQualifiers   SEQUENCE SIZE (1..MAX) OF
                              SigPolicyQualifierInfo OPTIONAL
}

SignaturePolicyImplied ::= NULL

SigPolicyId ::= OBJECT IDENTIFIER

SigPolicyHash ::= OtherHashAlgAndValue

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 {

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        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 {
    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-

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    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 must 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 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 X.509 :
see section 10.3

-- Content Time-Stamp

    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}

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ContentTimestamp::= TimeStampToken

-- Validation Data

-- Signature Time-Stamp

    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 {

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    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 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
}

OtherRevVals ::= SEQUENCE {
   otherRevValType  OtherRevValType,
  otherRevVals      ANY DEFINED BY otherRevValType
}

OtherRevValType ::= OBJECT IDENTIFIER

-- ES-C Time-Stamp

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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 Time-Stamp

id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1) member-
    body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16)
    id-aa(2) 27}

ArchiveTimeStampToken ::= TimeStampToken

END -- ETS-ElectronicSignatureFormats-88syntax --

A.2  Definitions Using X.680 1997 ASN.1 Syntax

NOTE:  The ASN.1 module defined in clause A.1 has precedence over that
defined in clause A.2 in the case of any conflict.

      ETS-ElectronicSignatureFormats-97Syntax { iso(1) member-body(2)
      us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) id-mod(0) 6}

DEFINITIONS EXPLICIT TAGS ::=

BEGIN

-- EXPORTS All -

IMPORTS

-- Cryptographic Message Syntax (CMS): RFC 2630

  ContentInfo, ContentType, id-data, id-signedData, SignedData,
  EncapsulatedContentInfo, SignerInfo, id-contentType,
  id-messageDigest, MessageDigest, id-signingTime,
  SigningTime, id-countersignature, Countersignature

   FROM CryptographicMessageSyntax
    { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)

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    smime(16) modules(0) cms(1) }


-- ESS Defined attributes: RFC 2634 (Enhanced Security Services
-- for S/MIME)

   id-aa-signingCertificate, SigningCertificate, IssuerSerial,
   id-aa-contentReference, ContentReference,
   id-aa-contentIdentifier, ContentIdentifier

  FROM ExtendedSecurityServices
    { iso(1) member-body(2) us(840) rsadsi(113549)
       pkcs(1) pkcs-9(9) smime(16) modules(0) ess(2) }

-- Internet X.509 Public Key Infrastructure
- - Certificate and CRL Profile:RFC 2459

   Certificate, AlgorithmIdentifier, CertificateList, Name,
   GeneralNames, GeneralName, DirectoryString, Attribute,
   AttributeTypeAndValue, AttributeType, AttributeValue,
   PolicyInformation.


  FROM PKIX1Explicit93
    {iso(1) identified-organization(3) dod(6) internet(1)
     security(5) mechanisms(5) pkix(7) id-mod(0)
     id-pkix1-explicit-88(1)}

-- X.509 '97 Authentication Framework

        AttributeCertificate

        FROM AuthenticationFramework
        {joint-iso-ccitt ds(5) module(1) authenticationFramework(7) 3}

-- OCSP 2560

      BasicOCSPResponse, ResponderID

  FROM OCSP

--  { OID not assigned }

-- Time Stamp Protocol Work in Progress 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)}

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-- S/MIME Object Identifier arcs used in this document
-- ===================================================

-- S/MIME  OID arc used in this document
-- id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2)
--             us(840) rsadsi(113549) pkcs(1) pkcs-9(9) 16 }

-- S/MIME Arcs
-- id-mod  OBJECT IDENTIFIER ::= { id-smime 0 }
-- modules
-- id-ct   OBJECT IDENTIFIER ::= { id-smime 1 }
-- content types
-- id-aa   OBJECT IDENTIFIER ::= { id-smime 2 }
-- attributes
-- id-spq  OBJECT IDENTIFIER ::= { id-smime 5 }
-- signature policy qualifier
-- id-cti  OBJECT IDENTIFIER ::= { id-smime 6 }
-- commitment type identifier

-- Definitions of Object Identifier arcs used in this document
-- ===========================================================

-- The allocation of OIDs to specific objects are given below with the
-- associated ASN.1 syntax definition

-- OID used referencing electronic signature mechanisms based on this
-- standard for use with the IDUP API (see annex 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) }

-- CMS Attributes Defined in this document
-- =======================================

-- Mandatory Electronic Signature Attributes
-- OtherSigningCertificate

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 THIS DOCUMENT
}

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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
}

-- 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
}

SignaturePolicyId ::= SEQUENCE {
        sigPolicyIdentifier   SigPolicyId,
        sigPolicyHash         SigPolicyHash,
        sigPolicyQualifiers   SEQUENCE SIZE (1..MAX) OF
                                SigPolicyQualifierInfo OPTIONAL
}

SignaturePolicyImplied ::= NULL

SigPolicyId ::= OBJECT IDENTIFIER

SigPolicyHash ::= OtherHashAlgAndValue

SigPolicyQualifierInfo ::= SEQUENCE {
        sigPolicyQualifierId    SIG-POLICY-QUALIFIER.&id
                                 ({SupportedSigPolicyQualifiers}),
        qualifier               SIG-POLICY-QUALIFIER.&Qualifier
                                ({SupportedSigPolicyQualifiers}
                                 {@sigPolicyQualifierId})OPTIONAL }

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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-sqt-unotice SIG-QUALIFIER-TYPE
                                            SPUserNotice
                                                        }

pointerToSigPolSpec SIG-POLICY-QUALIFIER ::= {
      SIG-POLICY-QUALIFIER-ID id-sqt-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

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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

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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 must 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 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 X.509 : see section 10.3

-- Content Time-Stamp

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

-- Validation Data

-- Signature Time-Stamp

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)

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    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  OTHER-REVOCATION-REF.&Type

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                                              }

OTHER-REVOCATION-REF ::= CLASS {
    &Type,
    &id  OBJECT IDENTIFIER UNIQUE }
  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 }

OtherRevVals ::= SEQUENCE {
   otherRevValType  OTHER-REVOCATION-VAL.&id,
  otherRevVals  OTHER-REVOCATION-VAL.&Type
                                               }

OTHER-REVOCATION-VAL ::= CLASS {
    &Type,
    &id  OBJECT IDENTIFIER UNIQUE }
  WITH SYNTAX {
    &Type ID &id }

-- ES-C Time-Stamp

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)

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    member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
    smime(16) id-aa(2) 26}

TimestampedCertsCRLs ::= TimeStampToken

-- Archive Time-Stamp

id-aa-ets-archiveTimestamp OBJECT IDENTIFIER ::= { iso(1)
   member-body(2)us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
   smime(16) id-aa(2) 27}

ArchiveTimeStampToken ::= TimeStampToken

END                -- ETS-ElectronicSignatureFormats-97Syntax

Annex B (informative): General Description

   This annex captures the concepts that apply to this document and the
   rational for the elements of the specification defined using ASN.1 in
   the main text of this document.

   The specification below includes a description why the component is
   needed, with a brief description of the vulnerabilities and threats
   and the manner by which they are countered.

B.1  The Signature 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 external data
   like a contract being referenced 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.

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   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 electronic signature the parts of the
   signature policy which specify the electronic rules for the creation
   and validation of the electronic signature also needs to be in a
   computer processable form.

   The signature policy thus includes the following:

      *  Information about the signature policy that can be displayed to
         the signer or the verifiers.
      *  Rules, which apply to functionality, covered by this document
         (referred to as the Signature Validation Policy).
      *  Rules which may be implied through adoption of Certificate
         Policies that apply to the electronic signature (e.g., rules
         for ensuring the secrecy of the private signing key).
      *  Rules, which relate to the environment used by the signer,
         e.g., the use of an agreed CAD (Card Accepting Device) used in
         conjunction with a smart card.

   An explicit Signature Validation Policy may be structured so that it
   can be computer processable.  Any format of the signature validation
   policy is allowed by this document.  However, for a given explicit
   signature policy there must be one definitive form that has a unique
   binary encoded value.

   The Signature Validation Policy includes rules regarding use of TSPs
   (CA, Attribute Authorities, Time Stamping Authorities) as well as
   rules defining the components of the electronic signature that must
   be provided by the signer with data required by the verifier to
   provide long term proof.

B.2  Signed Information

   The information being signed may be defined as a MIME-encapsulated
   message which 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 text (e.g., EDIFACT), free text or of fields from an
   electronic form (e-form).  For example, the Adobe(tm) format "pdf"
   may be used or the eXtensible Mark up Language (XML).

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B.3  Components of an Electronic Signature

B.3.1  Reference to the Signature Policy

   The definition of electronic signature includes: "a commitment has
   been explicitly endorsed under a "Signature policy", at a given time,
   by a signer under an identifier, e.g., a name or a pseudonym, and
   optionally a role".

   When two independent parties want to evaluate an electronic
   signature, it is fundamental that they get the same result.  To meet
   this requirement same signature policy must be used by the signer and
   verifier.

   The signature policy may be explicitly identified or may be implied
   by the semantics of the data being signed and other external data
   which designate the signature policy to be used.

   By signing over the signature policy identifier the signer explicitly
   indicates that he or she has applied the signature policy in creating
   the signature.  Thus, undertakes any explicit or implied commitments.

   In order to unambiguously identify an explicit signature policy that
   is to be used to verify the signature an identifier and hash of the
   "Signature policy" shall be part of the signed data.  Additional
   information about the explicit policy (e.g., web reference to the
   document) may be carried as "qualifiers" to the signature policy
   identifier.

   When the signature policy not explicitly identified, but is implied
   by the semantics of the data being signed, then the signature will
   include a signature policy identifier that indicates that the
   signature policy is implied.  In this case the verification rules
   must be determined by using other external data which will designate
   the signature policy to be used.  If it may be determined from the
   context that all the documents to be verified refer to the same
   signature policy, then that policy may be predetermined or fixed
   within the application.

   In order to identify unambiguously the "Signature Validation Policy"
   to be used to verify the signature an identifier and hash of the
   "Signature policy" must be part of the signed data.  Additional
   information about the policy (e.g., web reference to the document)
   may be carried as "qualifiers" to the signature policy identifier.

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B.3.2  Commitment Type Indication

   The definition of electronic signature includes: "a commitment has
   been explicitly endorsed under a signature policy, at a given time,
   by a signer under an identifier, e.g., a name or a pseudonym, and
   optionally a role".

   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 commitment types indications must be
   specified either as part of the signature policy or may be registered
   for generic use across multiple policies.

   If a signature includes a commitment type indication other than one
   of those recognized under the signature policy the signature must be
   treated as invalid.

   How commitment is indicated using the semantics of the data being
   signed is outside the scope of this document.

   NOTE:  Examples of commitment indicated through the semantics of the
   data being 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., EDIFACT purchase order).

      *  An implicit commitment which is a commitment made by the signer
         because the data being signed over has specific semantics
         (meaning) which is only interpretable by humans, (i.e., free
         text).

B.3.3  Certificate Identifier from the Signer

   The definition of the ETSI electronic signature includes: "a
   commitment has been explicitly endorsed under a signature policy, at
   a given time, by a signer under an identifier, e.g., a name or a
   pseudonym, and optionally a role."

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   In many real 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., as a
   national or as an employee from a company.  Thus 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 of multiple use of private
   keys 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 subject to various substitution attacks.  An example of
   a substitution attack is a "bad" CA that would issue a certificate to
   someone with the public key of someone else.  If the certificate from
   the signer was simply appended to the signature and thus not
   protected by the signature, any one could substitute one certificate
   by another and the message would appear to be signed by some one
   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.

   Although it does not provide the same advantages as the previous
   technique, another technique to counter that threat has been
   identified.  It requires all CAs to perform a Proof Of Possession of
   the private key at the time of registration.  The problem with that
   technique is that it does not provide any guarantee at the time of
   verification and only some proof "after the event" may be obtained,
   if and only if the CA keeps the Proof Of Possession in audit trail.

   In order to identify unambiguously the certificate to be used for the
   verification of the signature an identifier of the certificate from
   the signer must be part of the signed data.

B.3.4  Role Attributes

   The definition of electronic signature includes: "a commitment has
   been explicitly endorsed under a non repudiation security policy, at
   a given time, by a signer under an identifier, e.g., a name or a
   pseudonym, and optionally a role."

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   While the name of the signer is important, the position of the signer
   within a company or an organization can be even more important.  Some
   contracts may only be valid if signed by a user in a particular role,
   e.g., a Sales Director.  In many cases whom the sales Director really
   is, is not that important but being sure that the signer is empowered
   by his company to be the Sales Director is fundamental.

   This document defines two different ways for providing this feature:

      *  by placing a claimed role name in the CMS signed attributes
         field;

      *  by placing a 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 certificate.
   However, it was decided not to follow this approach as it breaks the
   basic philosophy of the certificate being issued for one primary
   purpose.  Also, by using separate certificates for management of the
   signer's identity certificate and management of additional roles can
   simplify the management, as new identity keys need not be issued if a
   use of role is to be changed.

B.3.4.1  Claimed Role

   The signer may be trusted to state his own role without any
   certificate to corroborate this claim.  In which case the claimed
   role can be added to the signature as a signed attribute.

B.3.4.2  Certified Role

   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 Attribute Authority
   will be most of the time 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., one day.  While this
   requires that a new Attribute Certificate is 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

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   so, a reference to 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 to identify unambiguously the attribute certificate(s) to be
   used for the verification of the signature an identifier of the
   attribute certificate(s) from the signer must be part of the signed
   data.

B.3.5  Signer Location

   In some transactions the purported location of the signer at the time
   he or she applies his signature may need to be indicated.  For this
   reason an optional location indicator must be able to be included.

   In order to provide indication of the location of the signer at the
   time he or she applied his signature a  location attribute may be
   included in the signature.

B.3.6  Signing Time

   The definition of electronic signature includes: "a commitment has
   been explicitly endorsed under a signature policy, at a given time,
   by a signer under an identifier, e.g., a name or a pseudonym, and
   optionally a role."

   There are several ways to address this problem.  The solution adopted
   in this document is to sign over a time which the signer claims is
   the signing time (i.e., claimed signing time) and to require a
   trusted time stamp to be obtained when building a ES with Time-Stamp.
   When a verifier accepts a signature, the two times must be within
   acceptable limits.

   The solution that is adopted in this document offers the major
   advantage that electronic signatures can be generated without any
   on-line connection to a trusted time source (i.e., they may be
   generated off-line).

   Thus two dates and two signatures are required:

      *  a signing time indicated by the signer and which is part of the
         data signed by the signer (i.e., part of the basic electronic
         signature);

      *  a time indicated by a Time-Stamping Authority (TSA) which is
         signed over the digital signature value of the basic electronic
         signature.  The signer, verifier or both may obtain the TSA
         time-stamp.

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   In order for an electronic signature to be valid under a signature
   policy, it must be time-stamped by a TSA where the signing time as
   indicated by the signer and the time of time stamping as indicated by
   a TSA must be "close enough" to meet the requirements of the
   signature validation policy.

   "Close enough" means a few minutes, hours or even days according to
   the "Signature Validation Policy".

   NOTE:  The need for Time-Stamping is further explained in clause
   B.4.5.  A further optional attribute is defined in this document to
   time-stamp the content, to provide proof of the existence of the
   content, at the time indicated by the time-stamp.

   Using this optional attribute a trusted secure time may be obtained
   before the document is signed and included under the digital
   signature.  This solution requires an on-line 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 (see 3.12.3, Content Time-Stamp).

   Also, the signing time should be between the time indicated by this
   time-stamp and time indicated by the ES-T time-stamp.

B.3.7  Content Format

   When presenting signed data to a human user 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, sound or video) to be selected by the relying
   party a content hint may be indicated by the signer.  If a relying
   party system does not use the format specified in the content hints
   to present the data to the relying party, the electronic signature
   may not be valid.

B.4  Components of Validation Data

B.4.1  Revocation Status Information

   A verifier will have to prove 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 an on-line certificate status server (for
         example; obtained through the OCSP protocol).

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B.4.2  CRL Information

   When using CRLs to get revocation information, a verifier will have
   to make sure that he or she gets at the time of the first
   verification 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.  This involves checking that the signer certificate serial
   number is not included in the CRL.  The signer, the verifier or any
   other third party may obtain either this CRL.  If obtained by the
   signer, then it must 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 archived elsewhere 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.

   It may happen that the certificate serial number appears in the CRL
   but with the status "suspended" (i.e., on hold).  In such a case, the
   electronic signature is not yet valid, since it is not possible to
   know whether the certificate will or will not be revoked at the end
   of the suspension period.  If a decision has to be taken immediately
   then the signature has to be considered as invalid.  If a decision
   can wait until the end of the suspension period, then two cases are
   possible:

      *  the certificate serial number has disappeared from the list and
         thus the certificate can be considered as valid and that CRL
         must be captured and archived either by the verifier or
         elsewhere and be kept accessible for the purpose of
         arbitration.

      *  the certificate serial number has been maintained on the list
         with the status definitively revoked and thus the electronic
         signature must be considered as invalid and discarded.

   At this point the verifier may be convinced that he or she got a
   valid signature, but is not yet in a position to prove at a later
   time that the signature was verified as valid.  Before addressing
   this point, an alternative to CRL is to use OCSP responses.

B.4.3  OCSP Information

   When using OCSP to get revocation information , a verifier will have
   to make sure that he or she gets at the time of the first
   verification an OCSP response that contains the status "valid".  This

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   should be done as soon as possible after the generation of the
   signature.  The signer, the verifier or any other third party may
   fetch this OCSP response. Since OSCP responses are transient and thus
   are not archived by any TSP 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 them in some storage so
   that they can then be easily retrieved.

   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 electronic signature is not yet valid, since it
   is not possible to know whether the certificate will or will not be
   revoked at the end of the suspension period.  If a decision has to be
   taken immediately then the electronic signature has to be considered
   as invalid.  If a decision can wait until the end of the suspension
   period, then two cases are possible:

      *  An OCSP response with a valid status is obtained at a later
         date and thus the certificate can be considered as valid and
         that OCSP response must be captured.

      *  An OCSP response with an invalid status is obtained with a
         secondary status indicating that the certificate is
         definitively revoked and thus the electronic signature must be
         considered as invalid and discarded.

   As in the CRL case, at this point, the verifier may be convinced that
   he or she got a valid signature, but is not yet in a position to
   prove at a later time that the signature was verified as valid.

B.4.4  Certification Path

   A verifier will have to prove that the certification path was valid,
   at the time of the signature, up to a trust point according to the
   naming constraints and the certificate policy constraints from the
   "Signature Validation Policy".  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 trusted root of the "Signature Validation
   Policy".  In addition, it will be necessary to capture the Authority
   Revocation Lists (ARLs) to prove than none of the CAs from the chain
   was revoked at the time of the signature.

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   As in the OCSP case, at this point, the verifier may be convinced
   that he or she got a valid signature, but is not yet in a position to
   prove at a later time that the signature was verified as valid.

B.4.5  Time-Stamping for Long Life of Signature

   An important property for long standing signatures is that a
   signature, having been found once to be valid, must continue to be so
   months or years later.

   A signer, verifier or both may be required to provide on request,
   proof that a digital signature was created or verified during the
   validity period of the all the certificates that make up the
   certificate path.  In this case, the signer, verifier or both will
   also be required to provide proof that all the user and CA
   certificates used were not revoked when the signature was created or
   verified.

   It would be quite unacceptable, to consider a signature as invalid
   even if the keys or certificates were later compromised.  Thus there
   is a need to be able to demonstrate that the signature keys was valid
   around the time that the signature was created to provide long 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 must
   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.  A time 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 private key, provides evidence that the signature has been
   created before the key was revoked.

   If a recipient wants to hold a valid electronic signature he will
   have to ensure that he has obtained a valid time stamp for 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.

   It is important to note that signatures may be generated "off-line"
   and time-stamped at a later time by anyone, for example by the signer
   or any recipient interested in the value of the signature.  The time
   stamp can thus be provided by the signer together with the signed

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   document, or obtained by the recipient following receipt of the
   signed document.

   The time stamp is NOT a component of the Electronic Signature, but
   the essential component of the ES with Time-Stamp.

   It is required in this document that signer's digital signature value
   is time-stamped by a trusted source, known as a Time-Stamping
   Authority.

   This document requires that the signer's digital signature value is
   time-stamped by a trusted source before the electronic signature can
   become a ES with Complete validation data (ES-C).  The acceptable
   TSAs are specified in the Signature Validation Policy.

   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 two
   time stamps.

B.4.6  Time-Stamping before CA Key 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
   to provide on request, proof that the certification path and the
   revocation information used a 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 current 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.

      *  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.

   NOTE:  the signer, verifier or both may obtain the time-stamp.

B.4.6.1  Time-Stamping the ES with Complete validation data

   When an OCSP response is used, it is necessary to time stamp in
   particular that response in the case the key from the responder would
   be compromised.  Since the information contained in the OCSP response

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   is user specific and time specific, an individual time stamp is
   needed for every signature received.  Instead of placing the time
   stamp only over the certification path references and the revocation
   information references, which include the OCSP response, the time
   stamp is placed on the ES-C.  Since the certification path and
   revocation information references are included in the ES with
   Complete validation data 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 Complete Validation
   Data exist and could be used.

   Although the technique requires a time stamp for every signature, it
   is well suited for individual users wishing to have an integrity
   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 ES with eXtended validation data
   (ES-X), type 1 Time-Stamped in this 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 becomes
   a ES-X Long as defined by this document.

   A ES-X Long Time-Stamped is simply the concatenation of a ES-X Time-
   Stamped with a copy of the additional data being referenced.

B.4.6.2  Time-Stamping Certificates and Revocation Information

   References Time-Stamping each ES with Complete validation data as
   defined above 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 existing 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

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   compromised.  In the same way, time-stamping CA CRLs, will stop any
   attacker from issuing bogus CA CRLs which could be claimed to
   existing before the CA key was compromised.

   Time-Stamping of commonly used certificates and CRLs can be done
   centrally, e.g., inside a company or by a service provider.  This
   method reduces the amount of data the verifier has to time-stamp, for
   example it could reduce to just one time stamp per day (i.e., in the
   case were all the signers use the same CA and the CRL applies for the
   whole day).  The information that needs to be time stamped is not the
   actual certificates and CRLs but the unambiguous references to those
   certificates and CRLs.

   To comply with extended validation data, type 2 Time-stamped, this
   document requires the following:

      *  All the CA certificates references and revocation information
         references (i.e., CRLs) used in validating the ES-C are covered
         by one or more time-stamp.

   Thus a ES-C with a time-stamp signature value at time T1, can be
   proved valid if all the CA and CRL references are time-stamped at
   time T1+.

B.4.7  Time-Stamping for Long Life of Signature

   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 probability.

   Over a period of time weaknesses may occur in the cryptographic
   algorithms used to create an electronic signature (e.g., due to the
   time available for cryptoanalysis, or improvements in
   cryptoanalytical techniques).  Before this 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 this goal depending on the nature of the weakened
   cryptography.  In order to simplify, a single technique, called
   Archive validation data, covering all the cases is being used in this
   document.

   Archive validation data consists of the Complete validation data and
   the complete certificate and revocation data, time 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

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   cannot be assumed that the hash function used by the Time Stamping
   Authority is secure, then nested time-stamps of Archived Electronic
   Signature are required.

   The potential for Trusted Service Provider (TSP) key compromise
   should be significantly lower than user 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 or of the cracking of
   the algorithms used by the TSA.  TSAs (Time-Stamping Authorities)
   should have long keys (e.g., which at the time of drafting this
   document was 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 previous time stamp
   are no longer secure.  Archive validation data may thus bear multiple
   embedded time stamps.

B.4.8  Reference to Additional Data

   Using type 1 or 2 of Time-Stamped extended validation data verifiers
   still needs 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 external source
   like a trusted service provider, in which case referenced information
   that is provided as part of the ES with Complete validation data
   (ES-C) is adequate.  The actual certificates and CRL information
   reference in the ES-C can be gathered when needed for arbitration.

B.4.9  Time-Stamping for Mutual Recognition

   In some business scenarios both the signer and the verifier need to
   time-stamp their own copy of the signature value.  Ideally the two
   time-stamps should be as close as possible to each other.

   Example: A contract is signed by two parties A and B representing
   their respective organizations, to time-stamp the signer and verifier
   data two approaches are possible:

      *  under the terms of the contract pre-defined common "trusted"
         TSA may be used;

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      *  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 considered as valid, if both time-stamps
         were obtained in due time (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., 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 the signer
   together with the signed document, and /or obtained by the verifier
   following receipt of the signed document.

   The business scenarios may thus dictate that one or more of the
   long-term signature time-stamping methods describe above be used.
   This will need to be part of a mutually agreed the Signature
   Validation Policy with is part of the overall signature policy under
   which digital signature may be used to support the business
   relationship between the two parties.

B.4.10  TSA Key Compromise

   TSA servers should be built in such a way that once the private
   signature key is installed, that there is minimal likelihood of
   compromise over as long as possible period.  Thus the validity period
   for the TSA's keys should be as long as possible.

   Both the ES-T and the ES-C contain at least one time 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., outside its validity period),
   then the ES-A should be used.  For extremely long periods this may be
   applied repeatedly using new TSA keys.

B.5  Multiple Signatures

   Some electronic signatures may only be valid if they bear more than
   one signature.  This is the case generally when a contract is signed
   between two parties.  The ordering of the signatures may or may not

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   be important, i.e., one may or may not need to be applied before the
   other. Several forms of multiple and counter signatures may 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 must be provided.

   Embedded signatures are applied one after the other and are used
   where the order the signatures are applied is important.  The
   capability to sign over signed data must be provided.

   These forms are described in clause 3.13.  All other multiple
   signature schemes, e.g., a signed document with a countersignature,
   double countersignatures or multiple signatures, can be reduced to
   one or more occurrence of the above two cases.

Annex C (informative):  Identifiers and roles

C.1  Signer Name Forms

   The name used by the signer, held as the subject in the signer's
   certificate, must uniquely identify the entity.  The name must be
   allocated and verified on registration with the Certification
   Authority, either directly or indirectly through a Registration
   Authority, before being issued with a Certificate.

   This document places no restrictions on the form of the name.  The
   subject's name may be a distinguished name, as defined in [RFC2459],
   held in the subject field of the certificate, or any other name form
   held in the X.509 subjectAltName certificate extension field.  In the
   case that the subject has no distinguished name, the subject name can
   be an empty sequence and the subjectAltName extension must be
   critical.

C.2  TSP Name Forms

   All TSP name forms (Certification Authorities, Attribute Authorities
   and Time-Stamping Authorities) must be in the form of a distinguished
   name held in the subject field of the certificate.

   The TSP name form must include the legal jurisdiction (i.e., country)
   under which it operates and an identification for the organization
   providing the service.

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C.3  Roles and Signer Attributes

   Where a signer signs as an individual 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, with is directly associated with the signing key
   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 this case the first identity is carried in the
   subject/subjectAltName field of the signer's certificate as described
   above.

   This document supports the following means of providing a second form
   of identification:

      *  by placing a secondary name field containing a claimed role in
         the CMS signed attributes field;

      *  by placing an attribute certificate containing a certified role
         in the CMS signed attributes field.

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