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Network Working Group M. Myers Request for Comments: 2511 VeriSign Category: Standards Track C. Adams Entrust Technologies D. Solo Citicorp D. Kemp DoD March 1999 Internet X.509 Certificate Request Message Format Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (1999). All Rights Reserved. 1. Abstract This document describes the Certificate Request Message Format (CRMF). This syntax is used to convey a request for a certificate to a Certification Authority (CA) (possibly via a Registration Authority (RA)) for the purposes of X.509 certificate production. The request will typically include a public key and associated registration information. The key words "MUST", "REQUIRED", "SHOULD", "RECOMMENDED", and "MAY" in this document (in uppercase, as shown) are to be interpreted as described in RFC 2119. 2. Overview Construction of a certification request involves the following steps: a) A CertRequest value is constructed. This value may include the public key, all or a portion of the end-entity's (EE's) name, other requested certificate fields, and additional control information related to the registration process. Myers, et. al. Standards Track [Page 1] RFC 2511 Internet X.509 CRMF March 1999 b) A proof of possession (of the private key corresponding to the public key for which a certificate is being requested) value may be calculated across the CertRequest value. c) Additional registration information may be combined with the proof of possession value and the CertRequest structure to form a CertReqMessage. d) The CertReqMessage is securely communicated to a CA. Specific means of secure transport are beyond the scope of this specification. 3. CertReqMessage Syntax A certificate request message is composed of the certificate request, an optional proof of possession field and an optional registration information field. CertReqMessages ::= SEQUENCE SIZE (1..MAX) OF CertReqMsg CertReqMsg ::= SEQUENCE { certReq CertRequest, pop ProofOfPossession OPTIONAL, -- content depends upon key type regInfo SEQUENCE SIZE(1..MAX) of AttributeTypeAndValue OPTIONAL } The proof of possession field is used to demonstrate that the entity to be associated with the certificate is actually in possession of the corresponding private key. This field may be calculated across the contents of the certReq field and varies in structure and content by public key algorithm type and operational mode. The regInfo field SHOULD only contain supplementary information related to the context of the certification request when such information is required to fulfill a certification request. This information MAY include subscriber contact information, billing information or other ancillary information useful to fulfillment of the certification request. Information directly related to certificate content SHOULD be included in the certReq content. However, inclusion of additional certReq content by RAs may invalidate the pop field. Data therefore intended for certificate content MAY be provided in regInfo. See Section 8 and Appendix B for example regInfo contents. Myers, et. al. Standards Track [Page 2] RFC 2511 Internet X.509 CRMF March 1999 4. Proof of Possession (POP) In order to prevent certain attacks and to allow a CA/RA to properly check the validity of the binding between an end entity and a key pair, the PKI management operations specified here make it possible for an end entity to prove that it has possession of (i.e., is able to use) the private key corresponding to the public key for which a certificate is requested. A given CA/RA is free to choose how to enforce POP (e.g., out-of-band procedural means versus the CRMF in- band message) in its certification exchanges (i.e., this may be a policy issue). However, it is MANDATED that CAs/RAs MUST enforce POP by some means because there are currently many non-PKIX operational protocols in use (various electronic mail protocols are one example) that do not explicitly check the binding between the end entity and the private key. Until operational protocols that do verify the binding (for signature, encryption, and key agreement key pairs) exist, and are ubiquitous, this binding can only be assumed to have been verified by the CA/RA. Therefore, if the binding is not verified by the CA/RA, certificates in the Internet Public-Key Infrastructure end up being somewhat less meaningful. POP is accomplished in different ways depending on the type of key for which a certificate is requested. If a key can be used for multiple purposes (e.g., an RSA key) then any of the methods MAY be used. This specification allows for cases where POP is validated by the CA, the RA, or both. Some policies may require the CA to verify POP during certification, in which case the RA MUST forward the end entity's CertRequest and ProofOfPossession fields unaltered to the CA, and as an option MAY also verify POP. If the CA is not required by policy to verify POP, then the RA SHOULD forward the end entity's request and proof unaltered to the CA as above. If this is not possible (for example because the RA verifies POP by an out-of-band method), then the RA MAY attest to the CA that the required proof has been validated. If the CA uses an out-of-band method to verify POP (such as physical delivery of CA-generated private keys), then the ProofOfPossession field is not used. 4.1 Signature Keys For signature keys, the end entity can sign a value to prove possession of the private key. Myers, et. al. Standards Track [Page 3] RFC 2511 Internet X.509 CRMF March 1999 4.2 Key Encipherment Keys For key encipherment keys, the end entity can provide the private key to the CA/RA, or can be required to decrypt a value in order to prove possession of the private key. Decrypting a value can be achieved either directly or indirectly. The direct method is for the RA/CA to issue a random challenge to which an immediate response by the end entity is required. The indirect method is to issue a certificate which is encrypted for the end entity (and have the end entity demonstrate its ability to decrypt this certificate in a confirmation message). This allows a CA to issue a certificate in a form which can only be used by the intended end entity. 4.3 Key Agreement Keys For key agreement keys, the end entity can use any of the three methods given in Section 5.2 for encryption keys. For the direct and indirect methods, the end entity and the PKI management entity (i.e., CA or RA) must establish a shared secret key in order to prove that the end entity has possession of the private key (i.e., in order to decrypt the encrypted certificate or to construct the response to the issued challenge). Note that this need not impose any restrictions on the keys that can be certified by a given CA -- in particular, for Diffie-Hellman keys the end entity may freely choose its algorithm parameters -- provided that the CA can generate a short-term (or one-time) key pair with the appropriate parameters when necessary. The end entity may also MAC the certificate request (using a shared secret key derived from a Diffie-Hellman computation) as a fourth alternative for demonstrating POP. This option may be used only if the CA already has a DH certificate that is known to the end entity and if the EE is willing to use the CA's DH parameters. 4.4 Proof of Possession Syntax ProofOfPossession ::= CHOICE { raVerified [0] NULL, -- used if the RA has already verified that the requester is in -- possession of the private key signature [1] POPOSigningKey, keyEncipherment [2] POPOPrivKey, keyAgreement [3] POPOPrivKey } POPOSigningKey ::= SEQUENCE { poposkInput [0] POPOSigningKeyInput OPTIONAL, Myers, et. al. Standards Track [Page 4] RFC 2511 Internet X.509 CRMF March 1999 algorithmIdentifier AlgorithmIdentifier, signature BIT STRING } -- The signature (using "algorithmIdentifier") is on the -- DER-encoded value of poposkInput. NOTE: If the CertReqMsg -- certReq CertTemplate contains the subject and publicKey values, -- then poposkInput MUST be omitted and the signature MUST be -- computed on the DER-encoded value of CertReqMsg certReq. If -- the CertReqMsg certReq CertTemplate does not contain the public -- key and subject values, then poposkInput MUST be present and -- MUST be signed. This strategy ensures that the public key is -- not present in both the poposkInput and CertReqMsg certReq -- CertTemplate fields. POPOSigningKeyInput ::= SEQUENCE { authInfo CHOICE { sender [0] GeneralName, -- 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 PKMACValue }, -- used if no authenticated GeneralName currently exists for -- the sender; publicKeyMAC contains a password-based MAC -- on the DER-encoded value of publicKey publicKey SubjectPublicKeyInfo } -- from CertTemplate PKMACValue ::= SEQUENCE { algId AlgorithmIdentifier, -- the algorithm value shall be PasswordBasedMac -- {1 2 840 113533 7 66 13} -- the parameter value is PBMParameter value BIT STRING } POPOPrivKey ::= CHOICE { thisMessage [0] BIT STRING, -- posession is proven in this message (which contains the private -- key itself (encrypted for the CA)) subsequentMessage [1] SubsequentMessage, -- possession will be proven in a subsequent message dhMAC [2] BIT STRING } -- for keyAgreement (only), possession is proven in this message -- (which contains a MAC (over the DER-encoded value of the -- certReq parameter in CertReqMsg, which must include both subject -- and publicKey) based on a key derived from the end entity's -- private DH key and the CA's public DH key); -- the dhMAC value MUST be calculated as per the directions given -- in Appendix A. SubsequentMessage ::= INTEGER { Myers, et. al. Standards Track [Page 5] RFC 2511 Internet X.509 CRMF March 1999 encrCert (0), -- requests that resulting certificate be encrypted for the -- end entity (following which, POP will be proven in a -- confirmation message) challengeResp (1) } -- requests that CA/RA engage in challenge-response exchange with -- end entity in order to prove private key possession It is expected that protocols which incorporate this specification will include the confirmation and challenge-response messages necessary to a complete protocol. 4.4.1 Use of Password-Based MAC The following algorithm SHALL be used when publicKeyMAC is used in POPOSigningKeyInput to prove the authenticity of a request. 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]) The process of using PBMParameter to compute publicKeyMAC and so authenticate the origin of a public key certification request consists of two stages. The first stage uses shared secret information to produce a MAC key. The second stage MACs the public key in question using this MAC key to produce an authenticated value. Initialization of the first stage of algorithm assumes the existence of a shared secret distributed in a trusted fashion between CA/RA and end-entity. The salt value is appended to the shared secret and the one way function (owf) is 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, yielding a key K. In the second stage, K and the public key are inputs to HMAC as documented in [HMAC] to produce a value for publicKeyMAC as follows: publicKeyMAC = Hash( K XOR opad, Hash( K XOR ipad, public key) ) where ipad and opad are defined in [RFC2104]. Myers, et. al. Standards Track [Page 6] RFC 2511 Internet X.509 CRMF March 1999 The AlgorithmIdentifier for owf SHALL be SHA-1 {1 3 14 3 2 26} and for mac SHALL be HMAC-SHA1 {1 3 6 1 5 5 8 1 2}. 5. CertRequest syntax The CertRequest syntax consists of a request identifier, a template of certificate content, and an optional sequence of control information. CertRequest ::= SEQUENCE { certReqId INTEGER, -- ID for matching request and reply certTemplate CertTemplate, -- Selected fields of cert to be issued controls Controls OPTIONAL } -- Attributes affecting issuance CertTemplate ::= SEQUENCE { version [0] Version OPTIONAL, serialNumber [1] INTEGER OPTIONAL, signingAlg [2] AlgorithmIdentifier OPTIONAL, issuer [3] Name OPTIONAL, validity [4] OptionalValidity OPTIONAL, subject [5] Name OPTIONAL, publicKey [6] SubjectPublicKeyInfo OPTIONAL, issuerUID [7] UniqueIdentifier OPTIONAL, subjectUID [8] UniqueIdentifier OPTIONAL, extensions [9] Extensions OPTIONAL } OptionalValidity ::= SEQUENCE { notBefore [0] Time OPTIONAL, notAfter [1] Time OPTIONAL } --at least one must be present Time ::= CHOICE { utcTime UTCTime, generalTime GeneralizedTime } 6. Controls Syntax The generator of a CertRequest may include one or more control values pertaining to the processing of the request. Controls ::= SEQUENCE SIZE(1..MAX) OF AttributeTypeAndValue The following controls are defined (it is recognized that this list may expand over time): regToken; authenticator; pkiPublicationInfo; pkiArchiveOptions; oldCertID; protocolEncrKey. Myers, et. al. Standards Track [Page 7] RFC 2511 Internet X.509 CRMF March 1999 6.1 Registration Token Control A regToken control contains one-time information (either based on a secret value or on knowledge) intended to be used by the CA to verify the identity of the subject prior to issuing a certificate. Upon receipt of a certification request containing a value for regToken, the receiving CA verifies the information in order to confirm the identity claimed in the certification request. The value for regToken may be generated by the CA and provided out of band to the subscriber, or may otherwise be available to both the CA and the subscriber. The security of any out-of-band exchange should be commensurate with the risk of the CA accepting an intercepted value from someone other than the intended subscriber. The regToken control would typically be used only for initialization of an end entity into the PKI, whereas the authenticator control (see Section 7.2) would typically be used for initial as well as subsequent certification requests. In some instances of use the value for regToken could be a text string or a numeric quantity such as a random number. The value in the latter case could be encoded either as a binary quantity or as a text string representation of the binary quantity. To ensure a uniform encoding of values regardless of the nature of the quantity, the encoding of regToken SHALL be UTF8. 6.2 Authenticator Control. An authenticator control contains information used in an ongoing basis to establish a non-cryptographic check of identity in communication with the CA. Examples include: mother's maiden name, last four digits of social security number, or other knowledge-based information shared with the subscriber's CA; a hash of such information; or other information produced for this purpose. The value for an authenticator control may be generated by the subscriber or by the CA. In some instances of use the value for regToken could be a text string or a numeric quantity such as a random number. The value in the latter case could be encoded either as a binary quantity or as a text string representation of the binary quantity. To ensure a uniform encoding of values regardless of the nature of the quantity, the encoding of authenticator SHALL be UTF8. Myers, et. al. Standards Track [Page 8] RFC 2511 Internet X.509 CRMF March 1999 6.3 Publication Information Control The pkiPublicationInfo control enables subscribers to control the CA's publication of the certificate. It is defined by the following syntax: PKIPublicationInfo ::= SEQUENCE { action INTEGER { dontPublish (0), pleasePublish (1) }, pubInfos SEQUENCE SIZE (1..MAX) OF SinglePubInfo OPTIONAL } -- pubInfos MUST NOT be present if action is "dontPublish" -- (if action is "pleasePublish" and pubInfos is omitted, -- "dontCare" is assumed) SinglePubInfo ::= SEQUENCE { pubMethod INTEGER { dontCare (0), x500 (1), web (2), ldap (3) }, pubLocation GeneralName OPTIONAL } If the dontPublish option is chosen, the requester indicates that the PKI should not publish the certificate (this may indicate that the requester intends to publish the certificate him/herself). If the dontCare method is chosen, or if the PKIPublicationInfo control is omitted from the request, the requester indicates that the PKI MAY publish the certificate using whatever means it chooses. If the requester wishes the certificate to appear in at least some locations but wishes to enable the CA to make the certificate available in other repositories, set two values of SinglePubInfo for pubInfos: one with x500, web or ldap value and one with dontCare. The pubLocation field, if supplied, indicates where the requester would like the certificate to be found (note that the CHOICE within GeneralName includes a URL and an IP address, for example). 6.4 Archive Options Control The pkiArchiveOptions control enables subscribers to supply information needed to establish an archive of the private key corresponding to the public key of the certification request. It is defined by the following syntax: Myers, et. al. Standards Track [Page 9] RFC 2511 Internet X.509 CRMF March 1999 PKIArchiveOptions ::= CHOICE { encryptedPrivKey [0] EncryptedKey, -- the actual value of the private key keyGenParameters [1] KeyGenParameters, -- parameters which allow the private key to be re-generated archiveRemGenPrivKey [2] BOOLEAN } -- set to TRUE if sender wishes receiver to archive the private -- key of a key pair which the receiver generates in response to -- this request; set to FALSE if no archival is desired. EncryptedKey ::= CHOICE { encryptedValue EncryptedValue, envelopedData [0] EnvelopedData } -- The encrypted private key MUST be placed in the envelopedData -- encryptedContentInfo encryptedContent OCTET STRING. EncryptedValue ::= SEQUENCE { intendedAlg [0] AlgorithmIdentifier OPTIONAL, -- the intended algorithm for which the value will be used symmAlg [1] AlgorithmIdentifier OPTIONAL, -- the symmetric algorithm used to encrypt the value encSymmKey [2] BIT STRING OPTIONAL, -- the (encrypted) symmetric key used to encrypt the value keyAlg [3] AlgorithmIdentifier OPTIONAL, -- algorithm used to encrypt the symmetric key valueHint [4] OCTET STRING OPTIONAL, -- a brief description or identifier of the encValue content -- (may be meaningful only to the sending entity, and used only -- if EncryptedValue might be re-examined by the sending entity -- in the future) encValue BIT STRING } KeyGenParameters ::= OCTET STRING An alternative to sending the key is to send the information about how to re-generate the key using the KeyGenParameters choice (e.g., for many RSA implementations one could send the first random numbers tested for primality). The actual syntax for this parameter may be defined in a subsequent version of this document or in another standard. Myers, et. al. Standards Track [Page 10] RFC 2511 Internet X.509 CRMF March 1999 6.5 OldCert ID Control If present, the OldCertID control specifies the certificate to be updated by the current certification request. The syntax of its value is: CertId ::= SEQUENCE { issuer GeneralName, serialNumber INTEGER } 6.6 Protocol Encryption Key Control If present, the protocolEncrKey control specifies a key the CA is to use in encrypting a response to CertReqMessages. This control can be used when a CA has information to send to the subscriber that needs to be encrypted. Such information includes a private key generated by the CA for use by the subscriber. The encoding of protocolEncrKey SHALL be SubjectPublicKeyInfo. 7. Object Identifiers The OID id-pkix has the value id-pkix OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) } -- arc for Internet X.509 PKI protocols and their components id-pkip OBJECT IDENTIFIER :: { id-pkix pkip(5) } -- Registration Controls in CRMF id-regCtrl OBJECT IDENTIFIER ::= { id-pkip regCtrl(1) } id-regCtrl-regToken OBJECT IDENTIFIER ::= { id-regCtrl 1 } id-regCtrl-authenticator OBJECT IDENTIFIER ::= { id-regCtrl 2 } id-regCtrl-pkiPublicationInfo OBJECT IDENTIFIER ::= { id-regCtrl 3 } id-regCtrl-pkiArchiveOptions OBJECT IDENTIFIER ::= { id-regCtrl 4 } id-regCtrl-oldCertID OBJECT IDENTIFIER ::= { id-regCtrl 5 } id-regCtrl-protocolEncrKey OBJECT IDENTIFIER ::= { id-regCtrl 6 } -- Registration Info in CRMF id-regInfo OBJECT IDENTIFIER ::= { id-pkip id-regInfo(2) } id-regInfo-asciiPairs OBJECT IDENTIFIER ::= { id-regInfo 1 } --with syntax OCTET STRING id-regInfo-certReq OBJECT IDENTIFIER ::= { id-regInfo 2 } --with syntax CertRequest Myers, et. al. Standards Track [Page 11] RFC 2511 Internet X.509 CRMF March 1999 8. Security Considerations The security of CRMF delivery is reliant upon the security mechanisms of the protocol or process used to communicate with CAs. Such protocol or process needs to ensure the integrity, data origin authenticity, and privacy of the message. Encryption of a CRMF is strongly recommended if it contains subscriber-sensitive information and if the CA has an encryption certificate that is known to the end entity. 9. References [HMAC] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed- Hashing for Message Authentication", RFC 2104, February 1997. 10. Acknowledgments The authors gratefully acknowledge the contributions of Barbara Fox, Warwick Ford, Russ Housley and John Pawling, whose review and comments significantly clarified and improved the utility of this specification. Myers, et. al. Standards Track [Page 12] RFC 2511 Internet X.509 CRMF March 1999 11. Authors' Addresses Michael Myers VeriSign, Inc. 1390 Shorebird Way Mountain View, CA 94019 EMail: mmyers@verisign.com Carlisle Adams Entrust Technologies 750 Heron Road, Suite E08 Ottawa, Canada, K1V 1A7 EMail: cadams@entrust.com Dave Solo Citicorp 666 Fifth Ave, 3rd Floor New York, Ny 10103 EMail: david.solo@citicorp.com David Kemp National Security Agency Suite 6734 9800 Savage Road Fort Meade, MD 20755 EMail: dpkemp@missi.ncsc.mil Myers, et. al. Standards Track [Page 13] RFC 2511 Internet X.509 CRMF March 1999 Appendix A. Constructing "dhMAC" This Appendix describes the method for computing the bit string "dhMAC" in the proof-of-possession POPOPrivKey structure for Diffie- Hellman certificate requests. 1. The entity generates a DH public/private key-pair. The DH parameters used to calculate the public SHOULD be those specified in the CA's DH certificate. From CA's DH certificate: CApub = g^x mod p (where g and p are the established DH parameters and x is the CA's private DH component) For entity E: DH private value = y Epub = DH public value = g^y mod p 2. The MACing process will then consist of the following steps. a) The value of the certReq field is DER encoded, yielding a binary string. This will be the 'text' referred to in [HMAC], the data to which HMAC-SHA1 is applied. b) A shared DH secret is computed, as follows, shared secret = Kec = g^xy mod p [This is done by the entity E as CApub^y and by the CA as Epub^x, where CApub is retrieved from the CA's DH certificate and Epub is retrieved from the actual certification request.] c) A key K is derived from the shared secret Kec and the subject and issuer names in the CA's certificate as follows: K = SHA1(DER-encoded-subjectName | Kec | DER-encoded-issuerName) where "|" means concatenation. If subjectName in the CA certificate is an empty SEQUENCE then DER-encoded-subjectAltName should be used instead; similarly, if issuerName is an empty SEQUENCE then DER-encoded-issuerAltName should be used instead. d) Compute HMAC-SHA1 over the data 'text' as per [RFC2104] as: SHA1(K XOR opad, SHA1(K XOR ipad, text)) Myers, et. al. Standards Track [Page 14] RFC 2511 Internet X.509 CRMF March 1999 where, opad (outer pad) = the byte 0x36 repeated 64 times and ipad (inner pad) = the byte 0x5C repeated 64 times. Namely, (1) Append zeros to the end of K to create a 64 byte string (e.g., if K is of length 16 bytes it will be appended with 48 zero bytes 0x00). (2) XOR (bitwise exclusive-OR) the 64 byte string computed in step (1) with ipad. (3) Append the data stream 'text' to the 64 byte string resulting from step (2). (4) Apply SHA1 to the stream generated in step (3). (5) XOR (bitwise exclusive-OR) the 64 byte string computed in step (1) with opad. (6) Append the SHA1 result from step (4) to the 64 byte string resulting from step (5). (7) Apply SHA1 to the stream generated in step (6) and output the result. Sample code is also provided in [RFC2104, RFC2202]. e) The output of (d) is encoded as a BIT STRING (the value "dhMAC"). 3. The proof-of-possession process requires the CA to carry out steps (a) through (d) and then simply compare the result of step (d) with what it received as the "dhMAC" value. If they match then the following can be concluded. 1) The Entity possesses the private key corresponding to the public key in the certification request (because it needed the private key to calculate the shared secret). 2) Only the intended CA can actually verify the request (because the CA requires its own private key to compute the same shared secret). This helps to protect from rogue CAs. References [RFC2104] Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed Hashing for Message Authentication", RFC 2104, February 1997. [RFC2202] Cheng, P. and R. Glenn, "Test Cases for HMAC-MD5 and HMAC- SHA-1", RFC 2202, September 1997. Myers, et. al. Standards Track [Page 15] RFC 2511 Internet X.509 CRMF March 1999 Acknowledgements The details of this Appendix were provided by Hemma Prafullchandra. Appendix B. Use of RegInfo for Name-Value Pairs The "value" field of the id-regInfo-utf8Pairs OCTET STRING (with "tag" field equal to 12 and appropriate "length" field) will contain a series of UTF8 name/value pairs. This Appendix lists some common examples of such pairs for the purpose of promoting interoperability among independent implementations of this specification. It is recognized that this list is not exhaustive and will grow with time and implementation experience. B.1. Example Name/Value Pairs When regInfo is used to convey one or more name-value pairs (via id- regInfo-utf8Pairs), the first and subsequent pairs SHALL be structured as follows: [name?value][%name?value]*% This string is then encoded into an OCTET STRING and placed into the regInfo SEQUENCE. Reserved characters are encoded using the %xx mechanism of [RFC1738], unless they are used for their reserved purposes. The following table defines a recommended set of named elements. The value in the column "Name Value" is the exact text string that will appear in the regInfo. Name Value ---------- version -- version of this variation of regInfo use corp_company -- company affiliation of subscriber org_unit -- organizational unit mail_firstName -- personal name component mail_middleName -- personal name component mail_lastName -- personal name component mail_email -- subscriber's email address jobTitle -- job title of subscriber employeeID -- employee identification number or string mailStop -- mail stop issuerName -- name of CA Myers, et. al. Standards Track [Page 16] RFC 2511 Internet X.509 CRMF March 1999 subjectName -- name of Subject validity -- validity interval For example: version?1%corp_company?Acme, Inc.%org_unit?Engineering% mail_firstName?John%mail_lastName?Smith%jobTitle?Team Leader% mail_email?john@acme.com% B.1.1. IssuerName, SubjectName and Validity Value Encoding When they appear in id-regInfo-utf8Pairs syntax as named elements, the encoding of values for issuerName, subjectName and validity SHALL use the following syntax. The characters [] indicate an optional field, ::= and | have their usual BNF meanings, and all other symbols (except spaces which are insignificant) outside non-terminal names are terminals. Alphabetics are case-sensitive. issuerName ::= <names> subjectName ::= <names> <names> ::= <name> | <names>:<name> <validity> ::= validity ? [<notbefore>]-[<notafter>] <notbefore> ::= <time> <notafter> ::= <time> Where <time> is UTC time in the form YYYYMMDD[HH[MM[SS]]]. HH, MM, and SS default to 00 and are omitted if at the and of value 00. Example validity encoding: validity?-19991231% is a validity interval with no value for notBefore and a value of December 31, 1999 for notAfter. Each name comprises a single character name form identifier followed by a name value of one or UTF8 characters. Within a name value, when it is necessary to disambiguate a character which has formatting significance at an outer level, the escape sequence %xx SHALL be used, where xx represents the hex value for the encoding concerned. The percent symbol is represented by %%. <name> ::= X<xname>|O<oname>|E<ename>|D<dname>|U<uname>|I<iname> Name forms and value formats are as follows: X.500 directory name form (identifier "X"): Myers, et. al. Standards Track [Page 17] RFC 2511 Internet X.509 CRMF March 1999 <xname> ::= <rdns> <rdns> ::= <rdn> | <rdns> , <rdn> <rdn> ::= <avas> <avas> ::= <ava> | <avas> + <ava> <ava> ::= <attyp> = <avalue> <attyp> ::= OID.<oid> | <stdat> Standard attribute type <stdat> is an alphabetic attribute type identifier from the following set: C (country) L (locality) ST (state or province) O (organization) OU (organizational unit) CN (common name) STREET (street address) E (E-mail address). <avalue> is a name component in the form of a UTF8 character string of 1 to 64 characters, with the restriction that in the IA5 subset of UTF8 only the characters of ASN.1 PrintableString may be used. Other name form (identifier "O"): <oname> ::= <oid> , <utf8string> E-mail address (rfc822name) name form (identifier "E"): <ename> ::= <ia5string> DNS name form (identifier "D"): <dname> ::= <ia5string> URI name form (identifier "U"): <uname> ::= <ia5string> IP address (identifier "I"): <iname> ::= <oid> For example: issuerName?XOU=Our CA,O=Acme,C=US% subjectName?XCN=John Smith, O=Acme, C=US, E=john@acme.com% References [RFC1738] Berners-Lee, T., Masinter, L. and M. McCahill, "Uniform Resource Locators (URL)", RFC 1738, December 1994. Myers, et. al. Standards Track [Page 18] RFC 2511 Internet X.509 CRMF March 1999 Appendix C. ASN.1 Structures and OIDs PKIXCRMF {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-crmf(5)} CRMF DEFINITIONS IMPLICIT TAGS ::= BEGIN IMPORTS -- Directory Authentication Framework (X.509) Version, AlgorithmIdentifier, Name, Time, SubjectPublicKeyInfo, Extensions, UniqueIdentifier 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)} -- Certificate Extensions (X.509) GeneralName FROM PKIX1Implicit88 {iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-implicit-88(2)} -- Cryptographic Message Syntax EnvelopedData FROM CryptographicMessageSyntax { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) cms(1) }; CertReqMessages ::= SEQUENCE SIZE (1..MAX) OF CertReqMsg CertReqMsg ::= SEQUENCE { certReq CertRequest, pop ProofOfPossession OPTIONAL, -- content depends upon key type regInfo SEQUENCE SIZE(1..MAX) OF AttributeTypeAndValue OPTIONAL } CertRequest ::= SEQUENCE { certReqId INTEGER, -- ID for matching request and reply certTemplate CertTemplate, -- Selected fields of cert to be issued controls Controls OPTIONAL } -- Attributes affecting issuance CertTemplate ::= SEQUENCE { version [0] Version OPTIONAL, serialNumber [1] INTEGER OPTIONAL, signingAlg [2] AlgorithmIdentifier OPTIONAL, issuer [3] Name OPTIONAL, validity [4] OptionalValidity OPTIONAL, subject [5] Name OPTIONAL, Myers, et. al. Standards Track [Page 19] RFC 2511 Internet X.509 CRMF March 1999 publicKey [6] SubjectPublicKeyInfo OPTIONAL, issuerUID [7] UniqueIdentifier OPTIONAL, subjectUID [8] UniqueIdentifier OPTIONAL, extensions [9] Extensions OPTIONAL } OptionalValidity ::= SEQUENCE { notBefore [0] Time OPTIONAL, notAfter [1] Time OPTIONAL } --at least one MUST be present Controls ::= SEQUENCE SIZE(1..MAX) OF AttributeTypeAndValue AttributeTypeAndValue ::= SEQUENCE { type OBJECT IDENTIFIER, value ANY DEFINED BY type } ProofOfPossession ::= CHOICE { raVerified [0] NULL, -- used if the RA has already verified that the requester is in -- possession of the private key signature [1] POPOSigningKey, keyEncipherment [2] POPOPrivKey, keyAgreement [3] POPOPrivKey } POPOSigningKey ::= SEQUENCE { poposkInput [0] POPOSigningKeyInput OPTIONAL, algorithmIdentifier AlgorithmIdentifier, signature BIT STRING } -- The signature (using "algorithmIdentifier") is on the -- DER-encoded value of poposkInput. NOTE: If the CertReqMsg -- certReq CertTemplate contains the subject and publicKey values, -- then poposkInput MUST be omitted and the signature MUST be -- computed on the DER-encoded value of CertReqMsg certReq. If -- the CertReqMsg certReq CertTemplate does not contain the public -- key and subject values, then poposkInput MUST be present and -- MUST be signed. This strategy ensures that the public key is -- not present in both the poposkInput and CertReqMsg certReq -- CertTemplate fields. POPOSigningKeyInput ::= SEQUENCE { authInfo CHOICE { sender [0] GeneralName, -- 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 PKMACValue }, -- used if no authenticated GeneralName currently exists for -- the sender; publicKeyMAC contains a password-based MAC -- on the DER-encoded value of publicKey Myers, et. al. Standards Track [Page 20] RFC 2511 Internet X.509 CRMF March 1999 publicKey SubjectPublicKeyInfo } -- from CertTemplate PKMACValue ::= SEQUENCE { algId AlgorithmIdentifier, -- algorithm value shall be PasswordBasedMac {1 2 840 113533 7 66 13} -- parameter value is PBMParameter value BIT STRING } 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]) POPOPrivKey ::= CHOICE { thisMessage [0] BIT STRING, -- posession is proven in this message (which contains the private -- key itself (encrypted for the CA)) subsequentMessage [1] SubsequentMessage, -- possession will be proven in a subsequent message dhMAC [2] BIT STRING } -- for keyAgreement (only), possession is proven in this message -- (which contains a MAC (over the DER-encoded value of the -- certReq parameter in CertReqMsg, which MUST include both subject -- and publicKey) based on a key derived from the end entity's -- private DH key and the CA's public DH key); -- the dhMAC value MUST be calculated as per the directions given -- in Appendix A. SubsequentMessage ::= INTEGER { encrCert (0), -- requests that resulting certificate be encrypted for the -- end entity (following which, POP will be proven in a -- confirmation message) challengeResp (1) } -- requests that CA engage in challenge-response exchange with -- end entity in order to prove private key possession -- Object identifier assignments -- id-pkix OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) 7 } -- arc for Internet X.509 PKI protocols and their components Myers, et. al. Standards Track [Page 21] RFC 2511 Internet X.509 CRMF March 1999 id-pkip OBJECT IDENTIFIER ::= { id-pkix 5 } -- Registration Controls in CRMF id-regCtrl OBJECT IDENTIFIER ::= { id-pkip 1 } -- The following definition may be uncommented for use with -- ASN.1 compilers which do not understand UTF8String. -- UTF8String ::= [UNIVERSAL 12] IMPLICIT OCTET STRING id-regCtrl-regToken OBJECT IDENTIFIER ::= { id-regCtrl 1 } --with syntax: RegToken ::= UTF8String id-regCtrl-authenticator OBJECT IDENTIFIER ::= { id-regCtrl 2 } --with syntax: Authenticator ::= UTF8String id-regCtrl-pkiPublicationInfo OBJECT IDENTIFIER ::= { id-regCtrl 3 } --with syntax: PKIPublicationInfo ::= SEQUENCE { action INTEGER { dontPublish (0), pleasePublish (1) }, pubInfos SEQUENCE SIZE (1..MAX) OF SinglePubInfo OPTIONAL } -- pubInfos MUST NOT be present if action is "dontPublish" -- (if action is "pleasePublish" and pubInfos is omitted, -- "dontCare" is assumed) SinglePubInfo ::= SEQUENCE { pubMethod INTEGER { dontCare (0), x500 (1), web (2), ldap (3) }, pubLocation GeneralName OPTIONAL } id-regCtrl-pkiArchiveOptions OBJECT IDENTIFIER ::= { id-regCtrl 4 } --with syntax: PKIArchiveOptions ::= CHOICE { encryptedPrivKey [0] EncryptedKey, -- the actual value of the private key keyGenParameters [1] KeyGenParameters, -- parameters which allow the private key to be re-generated archiveRemGenPrivKey [2] BOOLEAN } -- set to TRUE if sender wishes receiver to archive the private -- key of a key pair which the receiver generates in response to Myers, et. al. Standards Track [Page 22] RFC 2511 Internet X.509 CRMF March 1999 -- this request; set to FALSE if no archival is desired. EncryptedKey ::= CHOICE { encryptedValue EncryptedValue, envelopedData [0] EnvelopedData } -- The encrypted private key MUST be placed in the envelopedData -- encryptedContentInfo encryptedContent OCTET STRING. EncryptedValue ::= SEQUENCE { intendedAlg [0] AlgorithmIdentifier OPTIONAL, -- the intended algorithm for which the value will be used symmAlg [1] AlgorithmIdentifier OPTIONAL, -- the symmetric algorithm used to encrypt the value encSymmKey [2] BIT STRING OPTIONAL, -- the (encrypted) symmetric key used to encrypt the value keyAlg [3] AlgorithmIdentifier OPTIONAL, -- algorithm used to encrypt the symmetric key valueHint [4] OCTET STRING OPTIONAL, -- a brief description or identifier of the encValue content -- (may be meaningful only to the sending entity, and used only -- if EncryptedValue might be re-examined by the sending entity -- in the future) encValue BIT STRING } -- the encrypted value itself KeyGenParameters ::= OCTET STRING id-regCtrl-oldCertID OBJECT IDENTIFIER ::= { id-regCtrl 5 } --with syntax: OldCertId ::= CertId CertId ::= SEQUENCE { issuer GeneralName, serialNumber INTEGER } id-regCtrl-protocolEncrKey OBJECT IDENTIFIER ::= { id-regCtrl 6 } --with syntax: ProtocolEncrKey ::= SubjectPublicKeyInfo -- Registration Info in CRMF id-regInfo OBJECT IDENTIFIER ::= { id-pkip 2 } id-regInfo-utf8Pairs OBJECT IDENTIFIER ::= { id-regInfo 1 } --with syntax UTF8Pairs ::= UTF8String id-regInfo-certReq OBJECT IDENTIFIER ::= { id-regInfo 2 } Myers, et. al. Standards Track [Page 23] RFC 2511 Internet X.509 CRMF March 1999 --with syntax CertReq ::= CertRequest END Myers, et. al. Standards Track [Page 24] RFC 2511 Internet X.509 CRMF March 1999 Full Copyright Statement Copyright (C) The Internet Society (1999). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Myers, et. al. Standards Track [Page 25]