HTTP/1.1 200 OK Date: Tue, 09 Apr 2002 06:26:20 GMT Server: Apache/1.3.20 (Unix) Last-Modified: Fri, 14 Aug 1998 13:06:00 GMT ETag: "304947-89c4-35d43638" Accept-Ranges: bytes Content-Length: 35268 Connection: close Content-Type: text/plain PKIX Working Group Michael Myers(VeriSign) draft-ietf-pkix-ocsp-05.txt Rich Ankney (CertCo) Ambarish Malpani (ValiCert) Slava Galperin (Teknowledge) Carlisle Adams (Entrust Technologies) Expires in 6 months August 1998 X.509 Internet Public Key Infrastructure Online Certificate Status Protocol - OCSP Status of this Memo This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). 1. Abstract This document specifies a protocol useful in determining the current status of a digital certificate without requiring CRLs. Additional mechanisms addressing PKIX operational requirements are specified in separate documents. Section 2 provides an overview of the protocol. Section 3 establishes functional requirements, while section 4 provides details of the protocol. In section 5 we cover security issues with the protocol. Appendix A demonstrates OCSP over HTTP and appendix B accumulates ASN.1 syntactic elements. 2. Protocol Overview In lieu of or as a supplement to checking against a periodic CRL, it may be necessary to obtain timely status regarding a certificate's revocation state (cf. PKIX Part 1, Section 3.3). Examples include high- value funds transfer or large stock trades. The Online Certificate Status Protocol (OCSP) enables applications to determine the revocation state of an identified certificate. OCSP may be used to satisfy some of the operational requirements of providing more timely revocation information than is possible with CRLs. An Myers, Ankney, Malpani, Galperin, Adams [Page 1] INTERNET DRAFT August 1998 OCSP client issues a status request to an OCSP responder and suspends acceptance of the certificate in question until the responder provides a response. This protocol specifies the data that needs to be exchanged between an application checking the revocation status of a certificate and the server providing that status. 2.1 Request An OCSP request contains the following data: - protocol version - service request - target certificate identifier - optional extensions which MAY be processed by the OCSP Responder Upon receipt of a request, an OCSP Responder determines if: 1) the message is well formed, 2) the responder is configured to provide the requested service and 3) the request contains the information needed by the responder. If any one of the prior conditions are not met, the OCSP responder produces an error message; otherwise, it returns a definitive response. 2.2 Response OCSP responses can be of various types. However, there is one basic type of OCSP response that MUST be supported by all OCSP servers and clients. The rest of this section only describes this basic response type. An OCSP response consists of a response type and the bytes of the actual response. All definitive response messages SHALL be digitally signed. The key used to sign the response MUST belong to one of the following: - the CA who issued the certificate in question - a Trusted Responder whose public key is trusted by the requester - a CA Designated Responder (Authorized Responder) who holds a special certificate issued by the CA indicating that it may issue OCSP responses for that CA A definitive response message is composed of: - version of the response syntax - name of the responder - responses for each of the certificates in a request - optional extensions - signature algorithm OID - signature computed across hash of the response The response for each of the certificates in a request consists of Myers, Ankney, Malpani, Galperin, Adams [Page 2] INTERNET DRAFT August 1998 - target certificate identifier - certificate status value - response validity interval - optional extensions This specification defines the following definitive response indicators for use in the certificate status value: - notRevoked - revoked - unknown The notRevoked state indicates that the certificate is not revoked. It does not necessarily mean that the certificate was ever issued. Nor does it mean that the certificate is in its validity interval. A notRevoked state by an OCSP responder DOES NOT absolve the application of the responsibility of checking that the certificate is in its validity period and has been correctly signed. For example, it is quite possible that an OCSP responder returns the notRevoked state if a certificate was revoked, but has since expired (equivalent to a serial number being dropped from the CRL). (Please see 4.4.4 for an elaboration of this rule, where the responder can indicate that the notRevoked state applies to all certificates that have not expired before a specified time.) The revoked state indicates that the certificate has been revoked. The unknown state indicates that the responder doesn't know about the certificate being requested. 2.3 Exception Cases In case of errors, the OCSP Responder may return an error message. These messages are not signed. Errors can be of the following types: - malformedRequest - internalError - tryLater - certRequired - sigRequired A server produces the malformedRequest response if the request received does not conform to the OCSP syntax. The response internalError indicates that the OCSP responder reached an inconsistent internal state. The query should be retried, potentially with another responder. In the event that the OCSP responder is operational, but unable to return a status for the requested certificate, the tryLater response can be used to indicate that the service exists, but is temporarily unable to respond. Myers, Ankney, Malpani, Galperin, Adams [Page 3] INTERNET DRAFT August 1998 The response certRequired is returned in cases where the server requires the client to supply the certificate data itself in order to construct a response. The response sigRequired is returned in cases where the server requires the client sign the request in order to construct a response. 2.4 Semantics of thisUpdate, nextUpdate and producedAt Responses can contain three times in them - thisUpdate, nextUpdate and producedAt. The semantics of these fields are: - thisUpdate: The time at which the status being indicated is known to be correct - nextUpdate: The time at or before which newer information will be available about the status of the certificate - producedAt: The time at which the OCSP responder signed this response. If nextUpdate is not set, the responder is indicating that newer revocation information is available all the time. 2.5 Response Pre-production OCSP responders MAY pre-produce signed responses specifying the status of certificates at a specified time. The time at which the status was known to be correct SHALL be reflected in the thisUpdate field of the response. The time at or before which newer information will be available is reflected in the nextUpdate field, while the time at which the response was produced will appear in the producedAt field of the response. 2.6 OCSP Signature Authority Delegation The key that signs a certificate's revocation information need not be the same key that signed the certificate. A certificate's issuer explicitly delegates OCSP signing authority by issuing a certificate containing a unique value for extendedKeyUsage in the OCSP signer's certificate. 3. Functional Requirements 3.1 Certificate Content In order to convey to OCSP clients a well-known point of information access, CAs SHALL provide the capability to include the AuthorityInfoAccess extension (defined in PKIX Part 1, section 4.2.2.1) in certificates that can be checked using OCSP. Alternatively, the accessLocation for the OCSP provider may be configured locally at the OCSP client. CAs that support an OCSP service, either hosted locally or provided by an Authorized Responder, MAY provide a value for a Myers, Ankney, Malpani, Galperin, Adams [Page 4] INTERNET DRAFT August 1998 uniformResourceIndicator (URI) accessLocation and the OID value id-ad-ocsp for the accessMethod in the AccessDescription SEQUENCE. The value of the accessLocation field in the subject certificate defines the transport (e.g. HTTP) used to access the OCSP responder and may contain other transport dependent information (e.g. a URL). 3.2 Signed Response Acceptance Requirements Prior to accepting a signed response as valid, OCSP clients SHALL confirm that: a. The certificate identified in a received response corresponds to that which was identified in the corresponding request; b. The signature on the response is valid; c. The identity of the signer matches the intended recipient of the request. d. The signer is currently authorized to sign the response. e. The response is in its validity period. 4. Detailed Protocol The ASN.1 syntax imports terms defined in the X.509 Certificate and CRL Profile Internet Draft. For signature calculation, the data to be signed is encoded using the ASN.1 distinguished encoding rules (DER) [X.690]. ASN.1 EXPLICIT tagging is used as a default unless specified otherwise. The terms imported from elsewhere are: Extensions, CertificateSerialNumber, SubjectPublicKeyInfo, Name, AlgorithmIdentifier, CRLReason 4.1 Requests This section specifies the ASN.1 specification for a confirmation request. The actual formatting of the message could vary depending on the transport mechanism used (HTTP, SMTP, LDAP, etc.). 4.1.1 Request Syntax OCSPRequest ::= SEQUENCE { tbsRequest TBSRequest optionalSignature [0] Signature OPTIONAL } TBSRequest ::= SEQUENCE { version [0] EXPLICIT Version DEFAULT v1, requestorName [1] EXPLICIT GeneralName OPTIONAL, requestList SEQUENCE OF Request, requestExtensions [2] EXPLICIT Extensions OPTIONAL } Signature ::= SEQUENCE { signatureAlgorithm AlgorithmIdentifier, Myers, Ankney, Malpani, Galperin, Adams [Page 5] INTERNET DRAFT August 1998 signature BIT STRING, certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL} Version ::= INTEGER { v1(0) } Request ::= SEQUENCE { reqCert CertID, singleRequestExtensions [0] EXPLICIT Extensions OPTIONAL } CertID ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, issuerNameHash OCTET STRING, -- Hash of Issuer's DN issuerKeyHash OCTET STRING, -- Hash of Issuers public key serialNumber CertificateSerialNumber } issuerNameHash is the hash of the Issuer's distinguished name. The hash shall be calculated over the DER encoding of the issuer's name field in the certificate being checked. issuerKeyHash is the hash of the Issuer's public key. The hash shall be calculated over the value (excluding tag and length) of the subject public key field in the issuer's certificate. 4.1.2 Notes on the Request Syntax The primary reason to use both the name and the public key to identify the issuer is that it is possible that two CAs may choose to use the same Name (uniqueness in the Name is a recommendation that cannot be enforced). Two CAs will never, however, have the same public key unless the CAs either explicitly decided to share their private key, or the key of one of the CAs was compromised. While it is possible to identify a certificate by sending over either the entire certificate or just a CertID, it is recommended that clients use just the CertID to reduce the size of the request. However, certain OCSP responders MAY require the entire certificate whose status is to be determined. Support for extensions is OPTIONAL. The critical flag SHOULD NOT be set for any of them. This standard suggests several useful extensions in Section 4.5. Additional extensions MAY be defined in additional RFCs. Unrecognized extensions SHOULD be ignored. Requests may be signed or unsigned. For signed requests, the optionalSignature field is present, while it is absent for unsigned requests. 4.2 Response Syntax This section specifies the ASN.1 specification for a confirmation response. The actual formatting of the message could vary depending on the transport mechanism used (HTTP, SMTP, LDAP, etc.). Myers, Ankney, Malpani, Galperin, Adams [Page 6] INTERNET DRAFT August 1998 4.2.1 ASN.1 Specification of the OCSP Response An OCSP response at a minimum consists of a responseStatus field indicating the processing status of the prior request. If the value of responseStatus is one of the error conditions, responseBytes are not set. OCSPResponse ::= SEQUENCE { responseStatus OCSPResponseStatus, responseBytes [0] EXPLICIT ResponseBytes OPTIONAL } OCSPResponseStatus ::= ENUMERATED { successful (0), --Response has valid confirmations malformedRequest (1), --Illegal confirmation request internalError (2), --Internal error in issuer tryLater (3), --Try again later certRequired (4), --Must supply certificate sigRequired (5) --Must sign the request } The value for responseBytes consists of an OBJECT IDENTIFIER and a response syntax identified by that OID encoded as an OCTET STRING: ResponseBytes ::= SEQUENCE { responseType OBJECT IDENTIFIER, response OCTET STRING } For a basic OCSP responder, responseType will be id-pkix-ocsp-basic: id-pkix-ocsp OBJECT IDENTIFIER ::= { id-ad-ocsp } id-pkix-ocsp-basic OBJECT IDENTIFIER ::= { id-pkix-ocsp 1 } OCSP responders SHALL be capable of responding with responses of the id-pkix-ocsp-basic response type. Correspondingly, OCSP clients SHALL be capable of receiving and processing responses of the id-pkix-ocsp-basic response type. The value for response SHALL be the DER encoding of BasicOCSPResponse: BasicOCSPResponse ::= SEQUENCE { tbsResponseData ResponseData, signatureAlgorithm AlgorithmIdentifier, signature BIT STRING, certs [1] EXPLICIT SEQUENCE OF Certificate OPTIONAL } The value for signature SHALL be computed on the hash of the DER encoding ResponseData. ResponseData ::= SEQUENCE { version [0] EXPLICIT Version DEFAULT v1, responderID ResponderID, producedAt GeneralizedTime, responses SEQUENCE OF SingleResponse, responseExtensions [1] EXPLICIT Extensions OPTIONAL } Myers, Ankney, Malpani, Galperin, Adams [Page 7] INTERNET DRAFT August 1998 ResponderID ::= CHOICE { byName [0] Name, byKey [1] KeyHash } KeyHash ::= OCTET STRING --SHA-1 hash of responder's public key (excluding the tag and length fields) SingleResponse ::= SEQUENCE { certID CertID, certStatus CertStatus, thisUpdate GeneralizedTime, nextUpdate [0] EXPLICIT GeneralizedTime OPTIONAL, singleExtensions [1] EXPLICIT Extensions OPTIONAL } CertStatus ::= CHOICE { notRevoked [0] IMPLICIT NULL, revoked [1] IMPLICIT RevokedInfo, unknown [2] IMPLICIT UnknownInfo } RevokedInfo ::= SEQUENCE { revocationTime GeneralizedTime, revocationReason [0] EXPLICIT CRLReason OPTIONAL } UnknownInfo ::= NULL -- this can be replaced with an enumeration 4.2.2 Notes on OCSP Responses 4.2.2.1 Time The thisUpdate and nextUpdate fields define a recommended validity interval. This interval corresponds to the {thisUpdate, nextUpdate} interval in CRLs. Responses whose nextUpdate value is earlier than the local system time value SHOULD be considered unreliable. Responses whose thisUpdate time is later than the local system time SHOULD be considered unreliable. Responses where the nextUpdate value is not set are equivalent to a CRL with no time for nextUpdate (see section 2.3). The producedAt time is the time at which this response was signed. 4.2.2.2 Authorized Responders The key that signs a certificate's revocation information need not be the same key that signed the certificate. A certificate's issuer MAY explicitly delegate OCSP signing authority by issuing a certificate including an extendedKeyUsage extension in the OCSP signer's certificate containing the value id-kp-OCSPSigning. id-kp-OCSPSigning OBJECT IDENTIFIER ::= {id-kp 9} 4.2.2.3.1 Revocation Checking of an Authorized Responder Since an Authorized OCSP responder provides revocation information for a CA, OCSP clients need to know how to check that an authorized Myers, Ankney, Malpani, Galperin, Adams [Page 8] INTERNET DRAFT August 1998 responder's certificate has not been revoked. CAs may choose to deal with this problem in one of three ways: - A CA may specify that an OCSP client can trust a responder for the lifetime of the responder's authorization certificate. The CA does so by including the extension id-pkix-ocsp-nocheck. This SHOULD be a non- critical extension. The value of the extension should be NULL. CAs issuing such a certificate should realized that a compromise of the responder's key, is as serious as the compromise of the CA's key, at least for the validity period of this certificate. CA's may choose to issue this type of certificate with a very short lifetime and renew it frequently. - A CA may specify how the responder's certificate be checked for revocation. This can be done using CRL Distribution Points if the check should be done using CRLs or CRL Distribution Points, or Authority Information Access if the check should be done in some other way. Details for specifying either of these two mechanisms are available in PKIX Part 1. - A CA may choose not to specify any method of revocation checking for the responder's certificate, in which case, it would be up to the OCSP client's local security policy to decide whether that certificate should be checked for revocation or not. id-pkix-ocsp-nocheck OBJECT IDENTIFIER ::= { id-pkix-ocsp 5 } 4.3 Mandatory and Optional Cryptographic Algorithms Clients that request OCSP services SHALL be capable of processing responses signed used DSA keys identified by the DSA sig-alg-oid specified in section 7.2.2 of PKIX Part 1. Clients SHOULD also be capable of processing RSA signatures as specified in section 7.2.1 of PKIX Part 1. OCSP responders SHALL support the SHA1 hashing algorithm. 4.4 Extensions This section defines some standard extensions. Support for all extensions is OPTIONAL. For each extension, the definition indicates its syntax, processing performed by the OCSP Responder, and any extensions which are included in the corresponding response. 4.4.1 Nonce The nonce cryptographically binds a request and a response to prevent replay attacks. The nonce is included as one of the requestExtensions in requests, while in responses it would be included as one of the responseExtensions. In both the request and the response, the nonce will be identified by the object identifier id-pkix-ocsp-nonce, while the extnValue is the value of the nonce. id-pkix-ocsp-nonce OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 } Myers, Ankney, Malpani, Galperin, Adams [Page 9] INTERNET DRAFT August 1998 4.4.2 CRL References It may be desirable for the OCSP responder to indicate the CRL on which a revoked or onHold certificate is found. This can be useful where OCSP is used between repositories, and also as an auditing mechanism. The CRL may be specified by a URL (the URL at which the CRL is available), a number (CRL number) or a time (the time at which the relevant CRL was created). These extensions will be specified as singleExtensions. The identifier for this extension will be id-pkix-ocsp-crl, while the value will be CrlID. id-pkix-ocsp-crl OBJECT IDENTIFIER ::= { id-pkix-ocsp 3 } CrlID ::= SEQUENCE { crlUrl [0] EXPLICIT IA5String OPTIONAL, crlNum [1] EXPLICIT INTEGER OPTIONAL, crlTime [2] EXPLICIT GeneralizedTime OPTIONAL } For the choice crlUrl, the IA5String will specify the URL at which the CRL is available. For crlNum, the INTEGER will specify the value of the CRL number extension of the relevant CRL. For crlTime, the GeneralizedTime will indicate the time at which the relevant CRL was issued. 4.4.3 Acceptable Response Types An OCSP client MAY wish to specify the kinds of response types it understands. To do so, it SHOULD use an extension with the OID id-pkix-ocsp-response, and the value AcceptableResponses. The OIDs included in AcceptableResponses are the OIDs of the various response types this client can accept (e.g., id-pkix-ocsp-basic). id-pkix-ocsp-response OBJECT IDENTIFIER ::= { id-pkix-ocsp 4 } AcceptableResponses ::= SEQUENCE OF { id OBJECT IDENTIFIER } As noted in section 3.3, OCSP responders SHALL be capable of responding with responses of the id-pkix-ocsp-basic response type. Correspondingly, OCSP clients SHALL be capable of receiving and processing responses of the id-pkix-ocsp-basic response type. 4.4.4 Archive Cutoff An OCSP responder MAY choose to retain revocation information beyond a certificate’s expiration. The date obtained by subtracting this retention interval value from the producedAt time in a response is defined as the certificate’s “archive cutoff” date. OCSP-enabled applications would use an OCSP archive cutoff date to contribute to a proof that a digital signature was (or was not) reliable on the date it was produced even if the certificate needed to validate the signature has long since expired. Myers, Ankney, Malpani, Galperin, Adams [Page 10] INTERNET DRAFT August 1998 OCSP servers that provide support for such historical reference SHOULD include an archive cutoff date extension in responses. If included, this value SHALL be provided as an OCSP singleResponse extension identified by id-pkix-ocsp-archive-cutoff and of syntax GeneralizedTime: id-pkix-ocsp-archive-cutoff OBJECT IDENTIFIER ::= { id-pkix-ocsp 6 } archiveCutoff ::= GeneralizedTime To illustrate, if a server is operated with a 7-year retention interval policy and status was produced at time t1 then the value for archiveCutoff in the response would be (t1 - 7 years). 4.4.5 CRL Entry Extensions CRL Entry Extensions - specified in Section 5.3 of PKIX part I - are also supported as singleExtensions. 4.4.6 Service Locator An OCSP server may be operated in a mode whereby the server receives a request and routes it to the OCSP server which is known to be authoritative for the identified certificate. The serviceLocator request extension is defined for this purpose. id-pkix-ocsp-service-locator OBJECT IDENTIFIER ::= { id-pkix-ocsp 7 } ServiceLocator :: = SEQUENCE { issuer Name, locator AuthorityInfoAccessSyntax OPTIONAL } Values for these fields are obtained from the corresponding fields in the subject certificate. 5. Security Considerations For this service to be effective, certificate using systems must connect to the certificate status service provider. In the event such a connection cannot be obtained, certificate-using systems could implement CRL processing logic as a fall-back position. A denial of service vulnerability is evident with respect to a flood of queries. The production of a cryptographic signature significantly affects response generation cycle time, thereby exacerbating the situation. Unsigned error responses open up the protocol to another denial of service attack, where the attacker sends false error responses. The use of precomputed responses allows replay attacks in which an old (notRevoked) response is replayed prior to its expiration date but after the certificate has been revoked. Deployments of OCSP should carefully evaluate the benefit of precomputed responses against the probability of a replay attack and the costs associated with its successful execution. Myers, Ankney, Malpani, Galperin, Adams [Page 11] INTERNET DRAFT August 1998 The reliance of HTTP caching in some deployment scenarios may result in unexpected results if intermediate servers are incorrectly configured or are known to possess cache management faults. Implementors are advised to take the reliability of HTTP cache mechanisms into account when deploying OCSP over HTTP. 6. References [HTTP] Hypertext Transfer Protocol -- HTTP/1.1. R. Fielding, J. Gettys, J. Mogul, H. Frystyk and T. Berners-Lee, RFC 2068, January 1997. [MUSTSHOULD] Key words for use in RFCs to Indicate Requirement Levels, S. Bradner, RFC 2119, March 1997. [URL] Uniform Resource Locators (URL), T. Berners-Lee, L. Masinter, M. McCahill, RFC 1738, December 1994. 7. Author's Address Michael Myers VeriSign, Inc. 1390 Shorebird Way Mountain View, CA 94019 mmyers@verisign.com Rich Ankney CertCo, LLC 13506 King Charles Dr. Chantilly, VA 20151 rankney@erols.com Ambarish Malpani ValiCert, Inc. 3160 W. Bayshore Drive Palo Alto, CA 94303 ambarish@valicert.com 650.849.9880 Slava Galperin Teknowledge Corporation 1810 Embarcadero Road Palo Alto, CA galperin@teknowledge.com Carlisle Adams Entrust Technologies 750 Heron Road, Suite E08 Ottawa, Ontario K1V 1A7 Canada cadams@entrust.com Myers, Ankney, Malpani, Galperin, Adams [Page 12] INTERNET DRAFT August 1998 Appendix A A.1 OCSP over HTTP This section describes the formatting that will be done to the request and response to support HTTP. A.1.1 HTTP based OCSP requests can use either the GET or the POST method to submit their requests. To enable HTTP caching, small requests (that after encoding are less than 255 bytes), MAY be submitted using GET. If HTTP caching is not important, or the request is greater than 255 bytes, the request SHOULD be submitted using POST. Where privacy is a requirement, OCSP transactions exchanged using HTTP SHOULD be protected using either TLS or SSL. An OCSP request using the GET method is constructed as follows: GET {url}/{url-encoding of base-64 encoding of the DER encoding of the OCSPRequest} where {url} may be derived from the value of AuthorityInfoAccess or other local configuration of the OCSP client. An OCSP request using the POST method is constructed as follows: The Content-Type header has the value "application/ocsp-request" while the body of the message is the DER encoding of the OCSPRequest. A.1.2 Response An HTTP-based OCSP response is composed of the appropriate HTTP headers, followed by the DER encoding of the OCSPResponse. The Content-Type header has the value "application/ocsp-response". The Content-Length header SHOULD specify the length of the response. Other HTTP headers MAY be present and MAY be ignored if not understood by the requestor. Appendix B: OCSP in ASN.1 OCSP1 DEFINITIONS EXPLICIT TAGS::= BEGIN IMPORTS -- Directory Authentication Framework (X.509) Certificate, AlgorithmIdentifier, GeneralizedTime, CRLReason, FROM AuthenticationFramework { joint-iso-itu-t ds(5) module(1) authenticationFramework(7) 3 } Myers, Ankney, Malpani, Galperin, Adams [Page 13] INTERNET DRAFT August 1998 -- PKIX Certificate Extensions AuthorityInfoAcessSyntax 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)}; OCSPRequest ::= SEQUENCE { tbsRequest TBSRequest optionalSignature [0] Signature OPTIONAL } TBSRequest ::= SEQUENCE { version [0] EXPLICIT Version DEFAULT v1, requestorName [1] EXPLICIT GeneralName OPTIONAL, requestList SEQUENCE OF Request, requestExtensions [2] EXPLICIT Extensions OPTIONAL } Signature ::= SEQUENCE { signatureAlgorithm AlgorithmIdentifier, signature BIT STRING, certs [0] EXPLICIT SEQUENCE OF Certificate OPTIONAL } Version ::= INTEGER { v1(0) } Request ::= SEQUENCE { reqCert CertID, singleRequestExtensions [0] EXPLICIT Extensions OPTIONAL } CertID ::= SEQUENCE { hashAlgorithm AlgorithmIdentifier, issuerNameHash OCTET STRING, -- Hash of Issuer's DN issuerKeyHash OCTET STRING, -- Hash of Issuers public key serialNumber CertificateSerialNumber } OCSPResponse ::= SEQUENCE { responseStatus OCSPResponseStatus, responseBytes [0] EXPLICIT ResponseBytes OPTIONAL } OCSPResponseStatus ::= ENUMERATED { successful (0), --Response has valid confirmations malformedRequest (1), --Illegal confirmation request internalError (2), --Internal error in issuer tryLater (3), --Try again later certRequired (4), --Must supply certificate sigRequired (5) --Must sign the request } ResponseBytes ::= SEQUENCE { responseType OBJECT IDENTIFIER, response OCTET STRING } BasicOCSPResponse ::= SEQUENCE { tbsResponseData ResponseData, signatureAlgorithm AlgorithmIdentifier, signature BIT STRING, certs [1] EXPLICIT SEQUENCE OF Certificate OPTIONAL } Myers, Ankney, Malpani, Galperin, Adams [Page 14] INTERNET DRAFT August 1998 ResponseData ::= SEQUENCE { version [0] EXPLICIT Version DEFAULT v1, responderID ResponderID, producedAt GeneralizedTime, responses SEQUENCE OF SingleResponse, responseExtensions [1] EXPLICIT Extensions OPTIONAL } ResponderID ::= CHOICE { byName [0] Name, byKey [1] KeyHash } KeyHash ::= OCTET STRING --SHA-1 hash of responder's public key --(excluding the tag and length fields) SingleResponse ::= SEQUENCE { certID CertID, certStatus CertStatus, thisUpdate GeneralizedTime, nextUpdate [0] EXPLICIT GeneralizedTime OPTIONAL, singleExtensions [1] EXPLICIT Extensions OPTIONAL } CertStatus ::= CHOICE { notRevoked [0] IMPLICIT NULL, revoked [1] IMPLICIT RevokedInfo, unknown [2] IMPLICIT UnknownInfo } RevokedInfo ::= SEQUENCE { revocationTime GeneralizedTime, revocationReason [0] EXPLICIT CRLReason OPTIONAL } UnknownInfo ::= NULL -- this can be replaced with an enumeration archiveCutoff ::= GeneralizedTime AcceptableResponses ::= SEQUENCE OF { id OBJECT IDENTIFIER } ServiceLocator :: = SEQUENCE { issuer Name, locator AuthorityInfoAccessSyntax } -- Object Identifiers id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 } id-pkix-ocsp OBJECT IDENTIFIER ::= { id-ad-ocsp } id-pkix-ocsp-basic OBJECT IDENTIFIER ::= { id-pkix-ocsp 1 } id-pkix-ocsp-nonce OBJECT IDENTIFIER ::= { id-pkix-ocsp 2 } id-pkix-ocsp-crl OBJECT IDENTIFIER ::= { id-pkix-ocsp 3 } id-pkix-ocsp-response OBJECT IDENTIFIER ::= { id-pkix-ocsp 4 } id-pkix-ocsp-nocheck OBJECT IDENTIFIER ::= { id-pkix-ocsp 5 } id-pkix-ocsp-archive-cutoff OBJECT IDENTIFIER ::= { id-pkix-ocsp 6 } id-pkix-ocsp-service-locator OBJECT IDENTIFIER ::= { id-pkix-ocsp 7 } END Myers, Ankney, Malpani, Galperin, Adams [Page 15] INTERNET DRAFT August 1998 Appendix C: MIME registrations C.1 application/ocsp-request To: ietf-types@iana.org Subject: Registration of MIME media type application/ocsp-request MIME media type name: application MIME subtype name: ocsp-request Required parameters: None Optional parameters: None Encoding considerations: binary or Base64 Security considerations: Carries a request for information. This request may optionally be cryptographically signed. Interoperability considerations: None Published specification: IETF PKIX Working Group Draft on Online Certificate Status Protocol - OCSP Applications which use this media type: OCSP clients Additional information: Magic number(s): None File extension(s): .ORQ Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani Intended usage: COMMON Author/Change controller: Ambarish Malpani C.2 application/ocsp-response To: ietf-types@iana.org Subject: Registration of MIME media type application/ocsp-response MIME media type name: application MIME subtype name: ocsp-response Required parameters: None Optional parameters: None Encoding considerations: binary or Base64 Myers, Ankney, Malpani, Galperin, Adams [Page 16] INTERNET DRAFT August 1998 Security considerations: Carries a cryptographically signed response Interoperability considerations: None Published specification: IETF PKIX Working Group Draft on Online Certificate Status Protocol - OCSP Applications which use this media type: OCSP servers Additional information: Magic number(s): None File extension(s): .ORS Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani Intended usage: COMMON Author/Change controller: Ambarish Malpani Myers, Ankney, Malpani, Galperin, Adams [Page 17]