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RFC 2510

Internet X.509 Public Key Infrastructure Certificate Management Protocols

Pages: 72
Obsoleted by:  4210
Part 2 of 3 – Pages 19 to 38
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3. Data Structures

This section contains descriptions of the data structures required for PKI management messages. Section 4 describes constraints on their values and the sequence of events for each of the various PKI management operations. Section 5 describes how these may be encapsulated in various transport mechanisms.

3.1 Overall PKI Message

All of the messages used in this specification for the purposes of PKI management use the following structure: PKIMessage ::= SEQUENCE { header PKIHeader, body PKIBody, protection [0] PKIProtection OPTIONAL, extraCerts [1] SEQUENCE SIZE (1..MAX) OF Certificate OPTIONAL }
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   The PKIHeader contains information which is common to many PKI
   messages.

   The PKIBody contains message-specific information.

   The PKIProtection, when used, contains bits that protect the PKI
   message.

   The extraCerts field can contain certificates that may be useful to
   the recipient. For example, this can be used by a CA or RA to present
   an end entity with certificates that it needs to verify its own new
   certificate (if, for example, the CA that issued the end entity's
   certificate is not a root CA for the end entity).  Note that this
   field does not necessarily contain a certification path - the
   recipient may have to sort, select from, or otherwise process the
   extra certificates in order to use them.

3.1.1 PKI Message Header

All PKI messages require some header information for addressing and transaction identification. Some of this information will also be present in a transport-specific envelope; however, if the PKI message is protected then this information is also protected (i.e., we make no assumption about secure transport). The following data structure is used to contain this information: PKIHeader ::= SEQUENCE { pvno INTEGER { ietf-version2 (1) }, sender GeneralName, -- identifies the sender recipient GeneralName, -- identifies the intended recipient messageTime [0] GeneralizedTime OPTIONAL, -- time of production of this message (used when sender -- believes that the transport will be "suitable"; i.e., -- that the time will still be meaningful upon receipt) protectionAlg [1] AlgorithmIdentifier OPTIONAL, -- algorithm used for calculation of protection bits senderKID [2] KeyIdentifier OPTIONAL, recipKID [3] KeyIdentifier OPTIONAL, -- to identify specific keys used for protection transactionID [4] OCTET STRING OPTIONAL, -- identifies the transaction; i.e., this will be the same in -- corresponding request, response and confirmation messages senderNonce [5] OCTET STRING OPTIONAL, recipNonce [6] OCTET STRING OPTIONAL, -- nonces used to provide replay protection, senderNonce
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         -- is inserted by the creator of this message; recipNonce
         -- is a nonce previously inserted in a related message by
         -- the intended recipient of this message
         freeText        [7] PKIFreeText             OPTIONAL,
         -- this may be used to indicate context-specific instructions
         -- (this field is intended for human consumption)
         generalInfo     [8] SEQUENCE SIZE (1..MAX) OF
                                InfoTypeAndValue     OPTIONAL
         -- this may be used to convey context-specific information
         -- (this field not primarily intended for human consumption)
     }

     PKIFreeText ::= SEQUENCE SIZE (1..MAX) OF UTF8String
         -- text encoded as UTF-8 String (note:  each UTF8String SHOULD
         -- include an RFC 1766 language tag to indicate the language
         -- of the contained text)

   The pvno field is fixed (at one) for this version of this
   specification.

   The sender field contains the name of the sender of the PKIMessage.
   This name (in conjunction with senderKID, if supplied) should be
   usable to verify the protection on the message.  If nothing about the
   sender is known to the sending entity (e.g., in the init. req.
   message, where the end entity may not know its own Distinguished Name
   (DN), e-mail name, IP address, etc.), then the "sender" field MUST
   contain a "NULL" value; that is, the SEQUENCE OF relative
   distinguished names is of zero length. In such a case the senderKID
   field MUST hold an identifier (i.e., a reference number) which
   indicates to the receiver the appropriate shared secret information
   to use to verify the message.

   The recipient field contains the name of the recipient of the
   PKIMessage. This name (in conjunction with recipKID, if supplied)
   should be usable to verify the protection on the message.

   The protectionAlg field specifies the algorithm used to protect the
   message. If no protection bits are supplied (note that PKIProtection
   is OPTIONAL) then this field MUST be omitted; if protection bits are
   supplied then this field MUST be supplied.

   senderKID and recipKID are usable to indicate which keys have been
   used to protect the message (recipKID will normally only be required
   where protection of the message uses Diffie-Hellman (DH) keys).
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   The transactionID field within the message header MAY be used to
   allow the recipient of a response message to correlate this with a
   previously issued request. For example, in the case of an RA there
   may be many requests "outstanding" at a given moment.

   The senderNonce and recipNonce fields protect the PKIMessage against
   replay attacks.

   The messageTime field contains the time at which the sender created
   the message. This may be useful to allow end entities to correct
   their local time to be consistent with the time on a central system.

   The freeText field may be used to send a human-readable message to
   the recipient (in any number of languages).  The first language used
   in this sequence indicates the desired language for replies.

   The generalInfo field may be used to send machine-processable
   additional data to the recipient.

3.1.2 PKI Message Body

PKIBody ::= CHOICE { -- message-specific body elements ir [0] CertReqMessages, --Initialization Request ip [1] CertRepMessage, --Initialization Response cr [2] CertReqMessages, --Certification Request cp [3] CertRepMessage, --Certification Response p10cr [4] CertificationRequest, --PKCS #10 Cert. Req. -- the PKCS #10 certification request (see [PKCS10]) popdecc [5] POPODecKeyChallContent, --pop Challenge popdecr [6] POPODecKeyRespContent, --pop Response kur [7] CertReqMessages, --Key Update Request kup [8] CertRepMessage, --Key Update Response krr [9] CertReqMessages, --Key Recovery Request krp [10] KeyRecRepContent, --Key Recovery Response rr [11] RevReqContent, --Revocation Request rp [12] RevRepContent, --Revocation Response ccr [13] CertReqMessages, --Cross-Cert. Request ccp [14] CertRepMessage, --Cross-Cert. Response ckuann [15] CAKeyUpdAnnContent, --CA Key Update Ann. cann [16] CertAnnContent, --Certificate Ann. rann [17] RevAnnContent, --Revocation Ann. crlann [18] CRLAnnContent, --CRL Announcement conf [19] PKIConfirmContent, --Confirmation nested [20] NestedMessageContent, --Nested Message genm [21] GenMsgContent, --General Message genp [22] GenRepContent, --General Response error [23] ErrorMsgContent --Error Message }
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   The specific types are described in Section 3.3 below.

3.1.3 PKI Message Protection

Some PKI messages will be protected for integrity. (Note that if an asymmetric algorithm is used to protect a message and the relevant public component has been certified already, then the origin of message can also be authenticated. On the other hand, if the public component is uncertified then the message origin cannot be automatically authenticated, but may be authenticated via out-of-band means.) When protection is applied the following structure is used: PKIProtection ::= BIT STRING The input to the calculation of PKIProtection is the DER encoding of the following data structure: ProtectedPart ::= SEQUENCE { header PKIHeader, body PKIBody } There MAY be cases in which the PKIProtection BIT STRING is deliberately not used to protect a message (i.e., this OPTIONAL field is omitted) because other protection, external to PKIX, will instead be applied. Such a choice is explicitly allowed in this specification. Examples of such external protection include PKCS #7 [PKCS7] and Security Multiparts [RFC1847] encapsulation of the PKIMessage (or simply the PKIBody (omitting the CHOICE tag), if the relevant PKIHeader information is securely carried in the external mechanism); specification of external protection using PKCS #7 will be provided in a separate document. It is noted, however, that many such external mechanisms require that the end entity already possesses a public-key certificate, and/or a unique Distinguished Name, and/or other such infrastructure-related information. Thus, they may not be appropriate for initial registration, key-recovery, or any other process with "boot-strapping" characteristics. For those cases it may be necessary that the PKIProtection parameter be used. In the future, if/when external mechanisms are modified to accommodate boot-strapping scenarios, the use of PKIProtection may become rare or non-existent. Depending on the circumstances the PKIProtection bits may contain a Message Authentication Code (MAC) or signature. Only the following cases can occur:
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   - shared secret information

   In this case the sender and recipient share secret information
   (established via out-of-band means or from a previous PKI management
   operation).  PKIProtection will contain a MAC value and the
   protectionAlg will be the following:

     PasswordBasedMac ::= OBJECT IDENTIFIER --{1 2 840 113533 7 66 13}
     PBMParameter ::= SEQUENCE {
         salt                OCTET STRING,
         owf                 AlgorithmIdentifier,
         -- AlgId for a One-Way Function (SHA-1 recommended)
         iterationCount      INTEGER,
         -- number of times the OWF is applied
         mac                 AlgorithmIdentifier
         -- the MAC AlgId (e.g., DES-MAC, Triple-DES-MAC [PKCS11],
     }   -- or HMAC [RFC2104, RFC2202])

   In the above protectionAlg the salt value is appended to the shared
   secret input. The OWF is then applied iterationCount times, where the
   salted secret is the input to the first iteration and, for each
   successive iteration, the input is set to be the output of the
   previous iteration. The output of the final iteration (called
   "BASEKEY" for ease of reference, with a size of "H") is what is used
   to form the symmetric key. If the MAC algorithm requires a K-bit key
   and K <= H, then the most significant K bits of BASEKEY are used. If
   K > H, then all of BASEKEY is used for the most significant H bits of
   the key, OWF("1" || BASEKEY) is used for the next most significant H
   bits of the key, OWF("2" || BASEKEY) is used for the next most
   significant H bits of the key, and so on, until all K bits have been
   derived. [Here "N" is the ASCII byte encoding the number N and "||"
   represents concatenation.]

   - DH key pairs

   Where the sender and receiver possess Diffie-Hellman certificates
   with compatible DH parameters, then in order to protect the message
   the end entity must generate a symmetric key based on its private DH
   key value and the DH public key of the recipient of the PKI message.
   PKIProtection will contain a MAC value keyed with this derived
   symmetric key and the protectionAlg will be the following:
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     DHBasedMac ::= OBJECT IDENTIFIER --{1 2 840 113533 7 66 30}

     DHBMParameter ::= SEQUENCE {
         owf                 AlgorithmIdentifier,
         -- AlgId for a One-Way Function (SHA-1 recommended)
         mac                 AlgorithmIdentifier
         -- the MAC AlgId (e.g., DES-MAC, Triple-DES-MAC [PKCS11],
     }   -- or HMAC [RFC2104, RFC2202])

   In the above protectionAlg OWF is applied to the result of the
   Diffie-Hellman computation. The OWF output (called "BASEKEY" for ease
   of reference, with a size of "H") is what is used to form the
   symmetric key. If the MAC algorithm requires a K-bit key and K <= H,
   then the most significant K bits of BASEKEY are used. If K > H, then
   all of BASEKEY is used for the most significant H bits of the key,
   OWF("1" || BASEKEY) is used for the next most significant H bits of
   the key, OWF("2" || BASEKEY) is used for the next most significant H
   bits of the key, and so on, until all K bits have been derived. [Here
   "N" is the ASCII byte encoding the number N and "||" represents
   concatenation.]

   - signature

   Where the sender possesses a signature key pair it may simply sign
   the PKI message. PKIProtection will contain the signature value and
   the protectionAlg will be an AlgorithmIdentifier for a digital
   signature (e.g., md5WithRSAEncryption or dsaWithSha-1).

   - multiple protection

   In cases where an end entity sends a protected PKI message to an RA,
   the RA MAY forward that message to a CA, attaching its own protection
   (which MAY be a MAC or a signature, depending on the information and
   certificates shared between the RA and the CA). This is accomplished
   by nesting the entire message sent by the end entity within a new PKI
   message. The structure used is as follows.

     NestedMessageContent ::= PKIMessage

3.2 Common Data Structures

Before specifying the specific types that may be placed in a PKIBody we define some data structures that are used in more than one case.
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3.2.1 Requested Certificate Contents

Various PKI management messages require that the originator of the message indicate some of the fields that are required to be present in a certificate. The CertTemplate structure allows an end entity or RA to specify as much as it wishes about the certificate it requires. CertTemplate is identical to a Certificate but with all fields optional. Note that even if the originator completely specifies the contents of a certificate it requires, a CA is free to modify fields within the certificate actually issued. If the modified certificate is unacceptable to the requester, the Confirmation message may be withheld, or an Error Message may be sent (with a PKIStatus of "rejection"). See [CRMF] for CertTemplate syntax.

3.2.2 Encrypted Values

Where encrypted values (restricted, in this specification, to be either private keys or certificates) are sent in PKI messages the EncryptedValue data structure is used. See [CRMF] for EncryptedValue syntax. Use of this data structure requires that the creator and intended recipient respectively be able to encrypt and decrypt. Typically, this will mean that the sender and recipient have, or are able to generate, a shared secret key. If the recipient of the PKIMessage already possesses a private key usable for decryption, then the encSymmKey field MAY contain a session key encrypted using the recipient's public key.

3.2.3 Status codes and Failure Information for PKI messages

All response messages will include some status information. The following values are defined. PKIStatus ::= INTEGER { granted (0), -- you got exactly what you asked for grantedWithMods (1), -- you got something like what you asked for; the -- requester is responsible for ascertaining the differences rejection (2), -- you don't get it, more information elsewhere in the message
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         waiting                (3),
         -- the request body part has not yet been processed,
         -- expect to hear more later
         revocationWarning      (4),
         -- this message contains a warning that a revocation is
         -- imminent
         revocationNotification (5),
         -- notification that a revocation has occurred
         keyUpdateWarning       (6)
         -- update already done for the oldCertId specified in
         -- the key update request message
     }

   Responders may use the following syntax to provide more information
   about failure cases.

     PKIFailureInfo ::= BIT STRING {
     -- since we can fail in more than one way!
     -- More codes may be added in the future if/when required.
         badAlg           (0),
         -- unrecognized or unsupported Algorithm Identifier
         badMessageCheck  (1),
         -- integrity check failed (e.g., signature did not verify)
         badRequest       (2),
         -- transaction not permitted or supported
         badTime          (3),
         -- messageTime was not sufficiently close to the system time,
         -- as defined by local policy
         badCertId        (4),
         -- no certificate could be found matching the provided criteria
         badDataFormat    (5),
         -- the data submitted has the wrong format
         wrongAuthority   (6),
         -- the authority indicated in the request is different from the
         -- one creating the response token
         incorrectData    (7),
         -- the requester's data is incorrect (used for notary services)
         missingTimeStamp (8),
         -- when the timestamp is missing but should be there (by policy)
         badPOP           (9)
         -- the proof-of-possession failed
     }
     PKIStatusInfo ::= SEQUENCE {
         status        PKIStatus,
         statusString  PKIFreeText     OPTIONAL,
         failInfo      PKIFailureInfo  OPTIONAL
     }
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3.2.4 Certificate Identification

In order to identify particular certificates the CertId data structure is used. See [CRMF] for CertId syntax.

3.2.5 "Out-of-band" root CA public key

Each root CA must be able to publish its current public key via some "out-of-band" means. While such mechanisms are beyond the scope of this document, we define data structures which can support such mechanisms. There are generally two methods available: either the CA directly publishes its self-signed certificate; or this information is available via the Directory (or equivalent) and the CA publishes a hash of this value to allow verification of its integrity before use. OOBCert ::= Certificate The fields within this certificate are restricted as follows: - The certificate MUST be self-signed (i.e., the signature must be verifiable using the SubjectPublicKeyInfo field); - The subject and issuer fields MUST be identical; - If the subject field is NULL then both subjectAltNames and issuerAltNames extensions MUST be present and have exactly the same value; - The values of all other extensions must be suitable for a self- signed certificate (e.g., key identifiers for subject and issuer must be the same). OOBCertHash ::= SEQUENCE { hashAlg [0] AlgorithmIdentifier OPTIONAL, certId [1] CertId OPTIONAL, hashVal BIT STRING -- hashVal is calculated over the self-signed -- certificate with the identifier certID. } The intention of the hash value is that anyone who has securely received the hash value (via the out-of-band means) can verify a self- signed certificate for that CA.
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3.2.6 Archive Options

Requesters may indicate that they wish the PKI to archive a private key value using the PKIArchiveOptions structure See [CRMF] for PKIArchiveOptions syntax.

3.2.7 Publication Information

Requesters may indicate that they wish the PKI to publish a certificate using the PKIPublicationInfo structure. See [CRMF] for PKIPublicationInfo syntax.

3.2.8 Proof-of-Possession Structures

If the certification request is for a signing key pair (i.e., a request for a verification certificate), then the proof of possession of the private signing key is demonstrated through use of the POPOSigningKey structure. See [CRMF] for POPOSigningKey syntax, but note that POPOSigningKeyInput has the following semantic stipulations in this specification. POPOSigningKeyInput ::= SEQUENCE { authInfo CHOICE { sender [0] GeneralName, -- from PKIHeader (used only if an authenticated identity -- has been established for the sender (e.g., a DN from a -- previously-issued and currently-valid certificate)) publicKeyMAC [1] PKMACValue -- used if no authenticated GeneralName currently exists for -- the sender; publicKeyMAC contains a password-based MAC -- (using the protectionAlg AlgId from PKIHeader) on the -- DER-encoded value of publicKey }, publicKey SubjectPublicKeyInfo -- from CertTemplate } On the other hand, if the certification request is for an encryption key pair (i.e., a request for an encryption certificate), then the proof of possession of the private decryption key may be demonstrated in one of three ways. 1) By the inclusion of the private key (encrypted) in the CertRequest (in the PKIArchiveOptions control structure).
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      2) By having the CA return not the certificate, but an encrypted
         certificate (i.e., the certificate encrypted under a randomly-
         generated symmetric key, and the symmetric key encrypted under
         the public key for which the certification request is being
         made) -- this is the "indirect" method mentioned previously in
         Section 2.3.2.  The end entity proves knowledge of the private
         decryption key to the CA by MACing the PKIConfirm message using
         a key derived from this symmetric key.  [Note that if more than
         one CertReqMsg is included in the PKIMessage, then the CA uses
         a different symmetric key for each CertReqMsg and the MAC uses
         a key derived from the concatenation of all these keys.]  The
         MACing procedure uses the PasswordBasedMac AlgId defined in
         Section 3.1.

      3) By having the end entity engage in a challenge-response
         protocol (using the messages POPODecKeyChall and
         POPODecKeyResp; see below) between CertReqMessages and
         CertRepMessage -- this is the "direct" method mentioned
         previously in Section 2.3.2.  [This method would typically be
         used in an environment in which an RA verifies POP and then
         makes a certification request to the CA on behalf of the end
         entity.  In such a scenario, the CA trusts the RA to have done
         POP correctly before the RA requests a certificate for the end
         entity.]  The complete protocol then looks as follows (note
         that req' does not necessarily encapsulate req as a nested
         message):

                        EE            RA            CA
                         ---- req ---->
                         <--- chall ---
                         ---- resp --->
                                       ---- req' --->
                                       <--- rep -----
                                       ---- conf --->
                         <--- rep -----
                         ---- conf --->

   This protocol is obviously much longer than the 3-way exchange given
   in choice (2) above, but allows a local Registration Authority to be
   involved and has the property that the certificate itself is not
   actually created until the proof of possession is complete.

   If the cert. request is for a key agreement key (KAK) pair, then the
   POP can use any of the 3 ways described above for enc. key pairs,
   with the following changes:  (1) the parenthetical text of bullet 2)
   is replaced with "(i.e., the certificate encrypted under the
   symmetric key derived from the CA's private KAK and the public key
   for which the certification request is being made)"; (2) the first
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   parenthetical text of the challenge field of "Challenge" below is
   replaced with "(using PreferredSymmAlg (see Appendix B6) and a
   symmetric key derived from the CA's private KAK and the public key
   for which the certification request is being made)".  Alternatively,
   the POP can use the POPOSigningKey structure given in [CRMF] (where
   the alg field is DHBasedMAC and the signature field is the MAC) as a
   fourth alternative for demonstrating POP if the CA already has a D-H
   certificate that is known to the EE.

   The challenge-response messages for proof of possession of a private
   decryption key are specified as follows (see [MvOV97, p.404] for
   details).  Note that this challenge-response exchange is associated
   with the preceding cert. request message (and subsequent cert.
   response and confirmation messages) by the nonces used in the
   PKIHeader and by the protection (MACing or signing) applied to the
   PKIMessage.

     POPODecKeyChallContent ::= SEQUENCE OF Challenge
     -- One Challenge per encryption key certification request (in the
     -- same order as these requests appear in CertReqMessages).

     Challenge ::= SEQUENCE {
         owf                 AlgorithmIdentifier  OPTIONAL,
         -- MUST be present in the first Challenge; MAY be omitted in any
         -- subsequent Challenge in POPODecKeyChallContent (if omitted,
         -- then the owf used in the immediately preceding Challenge is
         -- to be used).
         witness             OCTET STRING,
         -- the result of applying the one-way function (owf) to a
         -- randomly-generated INTEGER, A.  [Note that a different
         -- INTEGER MUST be used for each Challenge.]
         challenge           OCTET STRING
         -- the encryption (under the public key for which the cert.
         -- request is being made) of Rand, where Rand is specified as
         --   Rand ::= SEQUENCE {
         --      int      INTEGER,
         --       - the randomly-generated INTEGER A (above)
         --      sender   GeneralName
         --       - the sender's name (as included in PKIHeader)
         --   }
     }

     POPODecKeyRespContent ::= SEQUENCE OF INTEGER
     -- One INTEGER per encryption key certification request (in the
     -- same order as these requests appear in CertReqMessages).  The
     -- retrieved INTEGER A (above) is returned to the sender of the
     -- corresponding Challenge.
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3.3 Operation-Specific Data Structures

3.3.1 Initialization Request

An Initialization request message contains as the PKIBody an CertReqMessages data structure which specifies the requested certificate(s). Typically, SubjectPublicKeyInfo, KeyId, and Validity are the template fields which may be supplied for each certificate requested (see Appendix B profiles for further information). This message is intended to be used for entities first initializing into the PKI. See [CRMF] for CertReqMessages syntax.

3.3.2 Initialization Response

An Initialization response message contains as the PKIBody an CertRepMessage data structure which has for each certificate requested a PKIStatusInfo field, a subject certificate, and possibly a private key (normally encrypted with a session key, which is itself encrypted with the protocolEncKey). See Section 3.3.4 for CertRepMessage syntax. Note that if the PKI Message Protection is "shared secret information" (see Section 3.1.3), then any certificate transported in the caPubs field may be directly trusted as a root CA certificate by the initiator.

3.3.3 Registration/Certification Request

A Registration/Certification request message contains as the PKIBody a CertReqMessages data structure which specifies the requested certificates. This message is intended to be used for existing PKI entities who wish to obtain additional certificates. See [CRMF] for CertReqMessages syntax. Alternatively, the PKIBody MAY be a CertificationRequest (this structure is fully specified by the ASN.1 structure CertificationRequest given in [PKCS10]). This structure may be required for certificate requests for signing key pairs when interoperation with legacy systems is desired, but its use is strongly discouraged whenever not absolutely necessary.
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3.3.4 Registration/Certification Response

A registration response message contains as the PKIBody a CertRepMessage data structure which has a status value for each certificate requested, and optionally has a CA public key, failure information, a subject certificate, and an encrypted private key. CertRepMessage ::= SEQUENCE { caPubs [1] SEQUENCE SIZE (1..MAX) OF Certificate OPTIONAL, response SEQUENCE OF CertResponse } CertResponse ::= SEQUENCE { certReqId INTEGER, -- to match this response with corresponding request (a value -- of -1 is to be used if certReqId is not specified in the -- corresponding request) status PKIStatusInfo, certifiedKeyPair CertifiedKeyPair OPTIONAL, rspInfo OCTET STRING OPTIONAL -- analogous to the id-regInfo-asciiPairs OCTET STRING defined -- for regInfo in CertReqMsg [CRMF] } CertifiedKeyPair ::= SEQUENCE { certOrEncCert CertOrEncCert, privateKey [0] EncryptedValue OPTIONAL, publicationInfo [1] PKIPublicationInfo OPTIONAL } CertOrEncCert ::= CHOICE { certificate [0] Certificate, encryptedCert [1] EncryptedValue } Only one of the failInfo (in PKIStatusInfo) and certificate (in CertifiedKeyPair) fields can be present in each CertResponse (depending on the status). For some status values (e.g., waiting) neither of the optional fields will be present. Given an EncryptedCert and the relevant decryption key the certificate may be obtained. The purpose of this is to allow a CA to return the value of a certificate, but with the constraint that only the intended recipient can obtain the actual certificate. The benefit of this approach is that a CA may reply with a certificate even in the absence of a proof that the requester is the end entity which can use the relevant private key (note that the proof is not obtained
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   until the PKIConfirm message is received by the CA). Thus the CA will
   not have to revoke that certificate in the event that something goes
   wrong with the proof of possession.

3.3.5 Key update request content

For key update requests the CertReqMessages syntax is used. Typically, SubjectPublicKeyInfo, KeyId, and Validity are the template fields which may be supplied for each key to be updated. This message is intended to be used to request updates to existing (non- revoked and non-expired) certificates. See [CRMF] for CertReqMessages syntax.

3.3.6 Key Update response content

For key update responses the CertRepMessage syntax is used. The response is identical to the initialization response. See Section 3.3.4 for CertRepMessage syntax.

3.3.7 Key Recovery Request content

For key recovery requests the syntax used is identical to the initialization request CertReqMessages. Typically, SubjectPublicKeyInfo and KeyId are the template fields which may be used to supply a signature public key for which a certificate is required (see Appendix B profiles for further information). See [CRMF] for CertReqMessages syntax. Note that if a key history is required, the requester must supply a Protocol Encryption Key control in the request message.

3.3.8 Key recovery response content

For key recovery responses the following syntax is used. For some status values (e.g., waiting) none of the optional fields will be present. KeyRecRepContent ::= SEQUENCE { status PKIStatusInfo, newSigCert [0] Certificate OPTIONAL, caCerts [1] SEQUENCE SIZE (1..MAX) OF Certificate OPTIONAL, keyPairHist [2] SEQUENCE SIZE (1..MAX) OF CertifiedKeyPair OPTIONAL }
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3.3.9 Revocation Request Content

When requesting revocation of a certificate (or several certificates) the following data structure is used. The name of the requester is present in the PKIHeader structure. RevReqContent ::= SEQUENCE OF RevDetails RevDetails ::= SEQUENCE { certDetails CertTemplate, -- allows requester to specify as much as they can about -- the cert. for which revocation is requested -- (e.g., for cases in which serialNumber is not available) revocationReason ReasonFlags OPTIONAL, -- the reason that revocation is requested badSinceDate GeneralizedTime OPTIONAL, -- indicates best knowledge of sender crlEntryDetails Extensions OPTIONAL -- requested crlEntryExtensions }

3.3.10 Revocation Response Content

The response to the above message. If produced, this is sent to the requester of the revocation. (A separate revocation announcement message MAY be sent to the subject of the certificate for which revocation was requested.) RevRepContent ::= SEQUENCE { status SEQUENCE SIZE (1..MAX) OF PKIStatusInfo, -- in same order as was sent in RevReqContent revCerts [0] SEQUENCE SIZE (1..MAX) OF CertId OPTIONAL, -- IDs for which revocation was requested (same order as status) crls [1] SEQUENCE SIZE (1..MAX) OF CertificateList OPTIONAL -- the resulting CRLs (there may be more than one) }

3.3.11 Cross certification request content

Cross certification requests use the same syntax (CertReqMessages) as for normal certification requests with the restriction that the key pair MUST have been generated by the requesting CA and the private key MUST NOT be sent to the responding CA. See [CRMF] for CertReqMessages syntax.
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3.3.12 Cross certification response content

Cross certification responses use the same syntax (CertRepMessage) as for normal certification responses with the restriction that no encrypted private key can be sent. See Section 3.3.4 for CertRepMessage syntax.

3.3.13 CA Key Update Announcement content

When a CA updates its own key pair the following data structure MAY be used to announce this event. CAKeyUpdAnnContent ::= SEQUENCE { oldWithNew Certificate, -- old pub signed with new priv newWithOld Certificate, -- new pub signed with old priv newWithNew Certificate -- new pub signed with new priv }

3.3.14 Certificate Announcement

This structure MAY be used to announce the existence of certificates. Note that this message is intended to be used for those cases (if any) where there is no pre-existing method for publication of certificates; it is not intended to be used where, for example, X.500 is the method for publication of certificates. CertAnnContent ::= Certificate

3.3.15 Revocation Announcement

When a CA has revoked, or is about to revoke, a particular certificate it MAY issue an announcement of this (possibly upcoming) event. RevAnnContent ::= SEQUENCE { status PKIStatus, certId CertId, willBeRevokedAt GeneralizedTime, badSinceDate GeneralizedTime, crlDetails Extensions OPTIONAL -- extra CRL details(e.g., crl number, reason, location, etc.) }
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   A CA MAY use such an announcement to warn (or notify) a subject that
   its certificate is about to be (or has been) revoked. This would
   typically be used where the request for revocation did not come from
   the subject concerned.

   The willBeRevokedAt field contains the time at which a new entry will
   be added to the relevant CRLs.

3.3.16 CRL Announcement

When a CA issues a new CRL (or set of CRLs) the following data structure MAY be used to announce this event. CRLAnnContent ::= SEQUENCE OF CertificateList

3.3.17 PKI Confirmation content

This data structure is used in three-way protocols as the final PKIMessage. Its content is the same in all cases - actually there is no content since the PKIHeader carries all the required information. PKIConfirmContent ::= NULL

3.3.18 PKI General Message content

InfoTypeAndValue ::= SEQUENCE { infoType OBJECT IDENTIFIER, infoValue ANY DEFINED BY infoType OPTIONAL } -- Example InfoTypeAndValue contents include, but are not limited to: -- { CAProtEncCert = {id-it 1}, Certificate } -- { SignKeyPairTypes = {id-it 2}, SEQUENCE OF AlgorithmIdentifier } -- { EncKeyPairTypes = {id-it 3}, SEQUENCE OF AlgorithmIdentifier } -- { PreferredSymmAlg = {id-it 4}, AlgorithmIdentifier } -- { CAKeyUpdateInfo = {id-it 5}, CAKeyUpdAnnContent } -- { CurrentCRL = {id-it 6}, CertificateList } -- where {id-it} = {id-pkix 4} = {1 3 6 1 5 5 7 4} -- This construct MAY also be used to define new PKIX Certificate -- Management Protocol request and response messages, or general- -- purpose (e.g., announcement) messages for future needs or for -- specific environments. GenMsgContent ::= SEQUENCE OF InfoTypeAndValue -- May be sent by EE, RA, or CA (depending on message content). -- The OPTIONAL infoValue parameter of InfoTypeAndValue will typically -- be omitted for some of the examples given above. The receiver is
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  -- free to ignore any contained OBJ. IDs that it does not recognize.
  -- If sent from EE to CA, the empty set indicates that the CA may send
  -- any/all information that it wishes.

3.3.19 PKI General Response content

GenRepContent ::= SEQUENCE OF InfoTypeAndValue -- The receiver is free to ignore any contained OBJ. IDs that it does -- not recognize.

3.3.20 Error Message content

ErrorMsgContent ::= SEQUENCE { pKIStatusInfo PKIStatusInfo, errorCode INTEGER OPTIONAL, -- implementation-specific error codes errorDetails PKIFreeText OPTIONAL -- implementation-specific error details }


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