Internet Draft T. Freeman draft-ietf-pkix-scvp-16.txt Microsoft Corp October 2004 R. Housley Expires in six months Vigil Security A. Malpani Malpani Consulting Services Simple Certificate Validation Protocol (SCVP) Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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 a "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html IPR Statement By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, or will be disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract SCVP allows a client to offload certificate handling to a server. The server can provide the client with a variety of valuable information about the certificate, such as whether the certificate is valid, a certification path to a trust anchor, and revocation status. SCVP has many purposes, including simplifying client implementations and allowing companies to centralize trust and policy management. INTERNET DRAFT SCVP October 2004 Table of Contents 1 Introduction....................................................5 1.1 SCVP overview and requirements...............................5 1.2 Terminology..................................................6 1.3 Validation Policies..........................................6 1.4 Validation Algorithm.........................................7 2 Protocol Overview...............................................8 3 Validation Request..............................................9 3.1 cvRequestVersion............................................11 3.1.1 queriedCerts............................................12 3.1.2 checks..................................................13 3.1.3 wantBack................................................14 3.1.4 validationPolicy........................................15 3.1.4.1 validationPolRef....................................16 3.1.5 validationAlg...........................................17 3.1.5.1 Default Validation Algorithm........................17 3.1.5.2 validationAlg.......................................18 3.1.5.2.1 Basic Validation Algorithm........................18 3.1.5.2.2 Basic Validation Algorithm Errors................19 3.1.5.2.3 Name Validation Algorithm........................20 3.1.5.2.4 Name Validation Algorithm Errors.................21 3.1.5.3 userPolicySet.......................................22 3.1.5.4 inhibitPolicyMapping................................22 3.1.5.5 requireExplicitPolicy...............................22 3.1.5.6 inhibitAnyPolicy....................................23 3.1.5.7 isCA................................................23 3.1.5.8 trustAnchors........................................23 3.1.5.9 keyUsages...........................................24 3.1.5.10 extendedKeyUsages..................................25 3.1.6 responseFlags...........................................25 3.1.6.1 responseRefHash.....................................25 3.1.6.2 responseValidationPolByRef..........................26 3.1.6.3 signResponse........................................26 3.1.7 serverContextInfo.......................................26 3.1.8 valididationTime........................................27 3.1.9 intermediateCerts.......................................28 3.1.10 revInfos...............................................28 3.1.11 producedAt.............................................29 3.1.12 queryExtensions........................................29 3.1.12.1 extnID.............................................29 3.1.12.2 critical...........................................29 3.1.12.3 extnValue..........................................30 3.2 requestorRef................................................30 3.3 requestNonce................................................30 3.4 requestExtensions...........................................31 3.4.1 extnID..................................................31 3.4.2 critical................................................31 3.4.3 extnValue...............................................31 3.5 dhPublicKey.................................................32 3.6 SCVP Request Authentication.................................32 4 Validation Response............................................32 Freeman, Housley, & Malpani [Page 2]
INTERNET DRAFT SCVP October 2004 4.1 cvResponseVersion...........................................36 4.2 policyID....................................................36 4.3 producedAt..................................................36 4.4 responseStatus..............................................36 4.5 respValidationPolicy........................................38 4.5.1 validationPolRef........................................39 4.5.2 validationPolValues.....................................39 4.5.2.1 validationAlg.......................................40 4.5.2.2 inhibitPolMap.......................................40 4.5.2.3 requireExplicitPol..................................40 4.5.2.4 inhibitAnyPol.......................................40 4.5.2.5 isCA................................................40 4.5.2.6 trustAnchors........................................40 4.5.2.7 keyUsage............................................40 4.5.2.8 extendedKeyUsage....................................40 4.5.2.9 validationPolicyAttr................................40 4.5.3 userFinalPolicySet......................................40 4.5.4 permittedSubtrees.......................................40 4.5.5 excludedSubtrees........................................41 4.5.6 validationPolicyAtt.....................................41 4.6 requestRef..................................................41 4.6.1 requestHash.............................................42 4.6.2 fullRequest.............................................42 4.7 requestorRef................................................42 4.8 requestorName...............................................42 4.9 responder...................................................43 4.10 replyObjects...............................................43 4.10.1 cert...................................................44 4.10.2 replyStatus............................................44 4.10.3 replyValTime...........................................45 4.10.4 replyChecks............................................45 4.10.5 replyWantBack..........................................47 4.10.6 validationAlg..........................................48 4.10.7 validationErrors.......................................48 4.10.8 nextUpdate.............................................48 4.10.9 certReplyExtensions....................................48 4.11 responseNonce..............................................49 4.12 serverContextInfo..........................................49 4.13 respExtensions.............................................50 4.14 SCVP Response Validation...................................50 4.14.1 Simple Key Validation..................................50 4.14.2 SCVP Server Certificate Validation.....................51 5 Server Policy Request..........................................51 5.1 vpRequestVersion............................................51 5.2 requestNonce................................................51 6 Validation Policy Response.....................................52 6.1 vpResponseVersion...........................................53 6.2 maxCVRequestVersion.........................................53 6.3 maxVPRequestVersion.........................................53 6.4 defaultPolicyID.............................................53 6.5 thisUpdate..................................................53 Freeman, Housley, & Malpani [Page 3]
INTERNET DRAFT SCVP October 2004 6.6 nextUpdate..................................................53 6.7 trustAnchors................................................54 6.8 validationPolicies..........................................54 6.9 validationAlgs..............................................54 6.10 authPolicies...............................................54 6.11 responseTypes..............................................55 6.12 dhPublicKeyInfo............................................55 6.13 clockSkew..................................................55 6.14 defaultValPolicy...........................................55 7 SCVP Server Relay..............................................56 8 SCVP ASN.1 Module..............................................56 9 Security Considerations........................................64 10 References....................................................65 10.1 Normative References.......................................65 10.2 Informative References.....................................67 11 Acknowledgments...............................................67 Appendix A -- MIME Registrations.................................67 A.1 application/cv-request......................................67 A.2 application/cv-response.....................................68 A.3 application/vp-request......................................69 A.4 application/vp-response.....................................70 Appendix B -- SCVP over HTTP.....................................70 B.1 SCVP Request................................................70 B.2 SCVP Response...............................................71 B.3 SCVP Policy Request.........................................71 B.4 SCVP Policy Response........................................72 Appendix C -- Author Contact Information.........................72 Full Copyright Statement.........................................73 Freeman, Housley, & Malpani [Page 4]
INTERNET DRAFT SCVP October 2004 1 Introduction Certificate validation is complex. If certificate handling is to be widely deployed in a variety of applications and environments, the amount of processing an application needs to perform before it can accept a certificate needs to be reduced. There are a variety of applications that can make use of public key certificates, but these applications are burdened with the overhead of constructing and validating the certification paths. SCVP reduces this overhead for two classes of certificate-using applications. The first class of application wants just two things. First, they want confirmation that the public key belongs to the identity named in the certificate. Second, they want to know if the public key can be used for the intended purpose. The client completely delegates certification path construction and validation to the SCVP server. This class of application is often referred to as delegated path validation (DPV). The second class of application can perform certification path validation, but these applications have no reliable method of constructing a certification path to a trust anchor. The client only delegates certification path construction to the SCVP server. This class of application is often referred to as delegated path discovery (DPD). 1.1 SCVP overview and requirements The SCVP meets the mandatory requirements documented in [RQMTS]. The primary goals of SCVP are to make it easier to deploy PKI- enabled applications and to allow central administration of PKI policies within an organization. SCVP can be used by clients that do much of the certificate processing themselves but simply want an untrusted server to collect information for them. However, when the client has complete trust in the SCVP server, SCVP can be used to delegate the work of certification path construction and validation, and SCVP can be used to ensure that policies are consistently enforced throughout an organization. Untrusted SCVP servers can provide clients the certification paths. They can also provide clients revocation information, such as CRLs and OCSP responses, and the client needs to validate the certification path constructed by the SCVP server. These services can be valuable to clients that do not include the protocols needed to find and download intermediate certificates, CRLs, and OCSP responses. Trusted SCVP servers can perform certification path construction and validation for the client. For a client that uses these Freeman, Housley, & Malpani [Page 5]
INTERNET DRAFT SCVP October 2004 services, the client inherently trusts the SCVP server as much as it would its own certification path validation software (if it contained such software). There are two main reasons that a client may want to trust such an SCVP server: 1. The client does not want to incur the overhead of including certification path validation software and running it for each certificate it receives. 2. The client is in an organization or community that wants to centralize its PKI policies. These policies might dictate that particular trust anchors are to be used and the types of policy checking that is to be performed during certification path validation. 1.2 Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [STDWORDS]. 1.3 Validation Policies A validation policy (as defined in RFC 3379 [RQMTS]) specifies the rules and parameters to be used by the SCVP server when validating a certificate. In SCVP, a validation policy can be either mutually agreed between client and server, and subsequently referenced in request, or explicitly expressed in the request by passing all of the necessary parameters. Policy definitions can be quite long and complex, and some policies may allow for the setting of a few parameters such as a set of trust anchors. The request can therefore be simplified if these previously agreed policy dependent parameters are referenced in the request by a mutually agreed OBJECT IDENTIFIER (OID) or URL value. The referenced value indicates either a partial or full set of parameters. The client can therefore omit these agreed parameters from the request, only passing any parameters which are not specified by the previously agreed policy. Therefore in the simplest form, with validation polices which define every parameter necessary, a SCVP request need only contain the certificate to be validated, the validation policy and any run-time parameters for the request. SCVP server also publishes its default validation policy settings. The default policy can be requested for validation and the client can override any default value in the request if required. The default values are also used when processing requests which reference a validation policy other than the default one that does not contain the full set of parameters necessary for validation and the client has also omitted the missing values in the request. Freeman, Housley, & Malpani [Page 6]
INTERNET DRAFT SCVP October 2004 Therefore a client can also simplify the request by omitting a parameter from a request if the default value published by the server is acceptable. The inputs to the basic certification path processing algorithm used by SCVP are defined by [PKIX-1] in section 6.1.1 and comprise: Certificate to be validated (by value or by reference) Validation time Set of Trust Anchors (by value or by reference) The initial policy set Initial policy mapping setting Initial any-Policy setting Initial explicit policy setting The basic certificate path processing algorithm also supports the following parameters which are defined in [PKIX-1] section 4 The basic certification path processing algorithm also supports the following parameters which are defined in [PKIX-1] section 4: The usage of the key contained in the certificate (e.g., key encipherment, key agreement, signature) Other application-specific purposes for which the certified public key may be used. 1.4 Validation Algorithm The validation algorithm is determined by agreement between the client and the server and is represented as an OID. The algorithm defines the checking that will be performed by the server to determine whether the certificate is valid, and it specifies any parameters defined in the policy. A validation algorithm is therefore one of the parameters to a validation policy. SCVP defines a basic validation algorithm which implements the certification path validation algorithm as defined in [PKIX-1]. New validation algorithms can be specified that define additional parameters if needed. Application-specific validation algorithms in addition to those defined in this document can be defined to meet specific requirements not covered by the basic validation algorithm. The validation algorithms documented here should serve as guide for the development of further application-specific validation algorithms. Freeman, Housley, & Malpani [Page 7]
INTERNET DRAFT SCVP October 2004 For example, a new application-specific validation algorithm might require the presence of a particular name form in the subject alternative name extension of the certificate. For a certification path to be considered valid under a particular validation policy, it MUST be a valid certification path as defined in [PKIX-1] and all validation policy constraints that apply to the certification path MUST be verified. Revocation checking is one aspect of certification path validation defined in [PKIX-1]. Therefore, the validation policy MUST specify the source of revocation information. Five alternatives are envisioned: 1. full CRLs (or full Authority Revocation Lists) have to be collected; 2. OCSP responses, using [OCSP], have to be collected; 3. delta CRLs and the relevant associated full CRLs (or full Authority Revocation Lists) are to be collected; 4. any available revocation information has to be collected; and 5. no revocation information need be collected. 2 Protocol Overview The SCVP uses a simple request-response model. That is, the SCVP client creates a request and sends it to the SCVP server, and then the SCVP server creates a single response and sends it to the client. The typical use of SCVP is expected to be over HTTP [HTTP], but it can also be used with email or any other protocol that can transport digitally signed objects. Appendix A and Appendix B provide the details necessary to use SCVP with HTTP. SCVP includes two request-response pairs. The primary request- response pair handles certificate validation. The secondary request-response pair is used to determine the list of validation policies and default parameters supported by a specific SCVP server. Section 3 defines the certificate validation request. Section 4 defines the corresponding certificate validation response. Section 5 defines the validation policies request. Section 6 defines the corresponding validation policies response. Freeman, Housley, & Malpani [Page 8]
INTERNET DRAFT SCVP October 2004 Appendix A registers MIME types for SCVP requests and responses, and Appendix B describes the use of these MIME types with HTTP. 3 Validation Request A SCVP client request to the server MUST be a single CVRequest item. When a CVRequest is encapsulated in a MIME body part, application/cv-request MUST be used. There are two forms of SCVP request: unsigned and signed. A signed request is used to authenticate the client to the server or to provide an anonymous client integrity over the request-response pair. A server MAY require all requests to be signed, and a server MAY discard all unsigned requests. Alternatively, a server MAY choose to process unsigned requests. The unsigned request consists of a CVRequest encapsulated in a CMS ContentInfo [CMS]. An overview of these structures are provided below and are only intended as illustrative. The definitive ASN.1 is found in [CMS]. Many details are not shown, but the way that SCVP makes use of CMS is clearly illustrated. ContentInfo { contentType id-ct-scvp-certValRequest, -- (1.2.840.113549.1.9.16.1.10) content CVRequest } The signed request consists of a CVRequest encapsulated in either a SignedData or AuthenticatedData which is in turn encapsulated in a ContentInfo. An overview of these structures are provided below. Again, many details are not shown, but the way that SCVP makes use of CMS is clearly illustrated. SignedData example: ContentInfo { contentType id-signedData, -- (1.2.840.113549.1.7.2) content SignedData } SignedData { version CMSVersion, digestAlgorithms DigestAlgorithmIdentifiers, encapContentInfo EncapsulatedContentInfo, certificates [0] IMPLICIT CertificateSet Optional, crls [1] IMPLICIT CertificateRevocationLists Optional, signerInfos SET OF SignerInfo } -- only one in SCVP SignerInfo { version CMSVersion, sid SignerIdentifier, Freeman, Housley, & Malpani [Page 9]
INTERNET DRAFT SCVP October 2004 digestAlgorithm DigestAlgorithmIdentifier, signedAttrs SignedAttributes, -- Required signatureAlgorithm SignatureAlgorithmIdentifier, signature SignatureValue, unsignedAttrs UnsignedAttributes } -- not used in SCVP EncapsulatedContentInfo { eContentType id-ct-scvp-certValRequest, -- (1.2.840.113549.1.9.16.1.10) eContent OCTET STRING } -- Contains CVRequest AuthenticatedData example: ContentInfo { contentType id-ct-authData, -- (1.2.840.113549.1.9.16.1.2) content AuthenticatedData } AuthenticatedData { version CMSVersion, originatorInfo OriginatorInfo, -- Optional recipientInfos RecipientInfos, -- Only SCVP server macAlgorithm MessageAuthenticationCodeAlgorithm, digestAlgorithm DigestAlgorithmIdentifier, -- Optional encapContentInfo EncapsulatedContentInfo, authAttrs AuthAttributes, -- Required mac MessageAuthenticationCode, unauthAttrs UnauthAttributes } -- not used in SCVP EncapsulatedContentInfo { eContentType id-ct-scvp-certValRequest, -- (1.2.840.113549.1.9.16.1.10) eContent OCTET STRING } -- Contains CVRequest All SCVP clients MUST support SignedData for signed requests and responses. An SCVP client SHOULD support authenticatedData for signed requests and responses. If the client uses signedData it MUST have a public key that has been bound to a subject identity by a certificate that conforms to the PKIX profile [PKIX-1] and that certificate MUST be suitable for signing the SCVP request. That is: If the key usage extension is present, either the digital signature or the non-repudiation bit MUST be asserted. If the extended key usage extension is present, it MUST contain either the client authentication OID, the SCVP client OID, or some other OID by agreement with the SCVP server. Freeman, Housley, & Malpani [Page 10]
INTERNET DRAFT SCVP October 2004 The client MUST put an unambiguous reference to its certificate in the SignedData or AuthenticatedData request. The client SHOULD include the signers certificate in the request, but MAY omit the certificate to reduce the size of the request. The client MAY include other certificates in the request to aid the validation of the signers certificates by the SCVP server. The syntax and semantics for SignedData, AuthenticatedData, and ContentInfo are defined in [CMS]. The syntax and semantics for CVRequest are defined below. The CVRequest item contains the client request. The CVRequest contains the cvRequestVersion and query items; and the CVRequest MAY also contain the requestorRef, requestNonce, and requestExtensions items. The CVRequest MUST have the following syntax: CVRequest ::= SEQUENCE { cvRequestVersion INTEGER, query Query, requestorRef [0] SEQUENCE SIZE (1..MAX) OF OCTET STRING OPTIONAL, requestNonce [1] OCTET STRING OPTIONAL, requestExtensions [2] Extensions OPTIONAL dhPublicKey [3] DHPublicKey OPTIONAL} Each of the items within the CVRequest is described in the following sections. 3.1 cvRequestVersion The cvRequestVersion item defines the version of the SCVP CVRequest used in a request. The subsequent response MUST use the same version number. The value of the cvRequestVersion item MUST be one (1) for a client implementing this specification. Future updates to this specification must specify other values if there are any changes to syntax or semantics. query item specifies one or more certificates that are the object of the request; the certificates can be either public key certificates [PKIX-1] or attribute certificates [PKIX-AC]. A query MUST contain a sequence of one or more queriedCerts items as well as one checks, one wantBack and one validationPolicy item; and a query MAY also contain responseRefHash, responseValidationPolByRef, signResponse, serverContextInfo, validationTime, intermediateCerts, revInfos, producedAt, and queryExtensions items. Query MUST have the following syntax: Query ::= SEQUENCE { queriedCerts SEQUENCE SIZE (1..MAX) OF CertReference, checks CertChecks, Freeman, Housley, & Malpani [Page 11]
INTERNET DRAFT SCVP October 2004 wantBack WantBack, validationPolicy ValidationPolicy, responseFlags ResponseFlags OPTIONAL, serverContextInfo [0] OCTET STRING OPTIONAL, validationTime [1] GeneralizedTime OPTIONAL, intermediateCerts [2] CertBundle OPTIONAL, revInfos [3] RevocationInfos OPTIONAL, producedAt [4] GeneralizedTime OPTIONAL, queryExtensions [5] Extensions OPTIONAL } The list of certificate references in the query item tells the server the certificate(s) for which the client wants information. The checks item specifies the checking that the client wants performed. The wantBack item specifies the objects that the client wants the server to return in the response. The validationPolicy item specifies the validation policy that the client wants the server to employ. The requestRefHash, responseValidationPolByRef and signResponse items allow the client to request optional features for the response. The serverContextInfo item tells the server that additional information from a previous request-response is desired. The validationTime item tells the date and time relative to which the client wants the server to perform the checks. The intermediateCerts and revInfos items provide context for the client request. The queryExtensions item provides for future expansion of the query syntax. The syntax and semantics of each of these items is discussed in the following sections. 3.1.1 queriedCerts The queriedCerts item, using the CertReference type, identifies the certificate that is the object of the request. The certificate is either a public key certificate or an attribute certificate. The certificate is either directly included or it is referenced. When referenced, a SHA-1 hash value [SHA-1] of the referenced item is included to ensure that the SCVP client and the SCVP server both obtain the same certificate when the referenced certificate is fetched. Certificate references use the ESSCertID type defined in [ESS]. CertReference has the following syntax: CertReference ::= CHOICE { pkc PKCReference, ac ACReference } PKCReference ::= CHOICE { cert [0] Certificate, pkcRef [1] ESSCertID } ACReference ::= CHOICE { attrCert [2] AttributeCertificate, acRef [3] ESSCertID } Freeman, Housley, & Malpani [Page 12]
INTERNET DRAFT SCVP October 2004 The ASN.1 definition of Certificate is imported from [PKIX-1]; the definition of AttributeCertificate is imported from [PKIX-AC]; and the definition of ESSCertID is imported from [ESS]. 3.1.2 checks The checks item describes the checking that the SCVP client wants the SCVP server to perform on the certificate(s) in the queriedCerts item. The checks item MUST contain a sequence of object identifiers (OIDs). Each OID tells the SCVP server what checking the client expects the server to perform. For each check specified in the request, the SCVP server MUST perform all of the requested checks, or return an error. Revocation status checking inherently includes certification path construction. Also, building a validated certification path does not imply revocation status checks. A server may still choose to perform revocation status checks when performing path construction, although this information cannot be returned to the client. The checks item uses the CertChecks type, which has the following syntax: CertChecks ::= SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER A list of OIDs indicates the checking that the client wants the SCVP server to perform on the certificate(s) in the queriedCerts item. For public key certificates, OIDs are defined for the following checks: - Build a certification path to a trust anchor; - Build a validated certification path to a trust anchor; and - Do revocation status checks on the certification path. For attribute certificates, OIDs are defined for the following checks: - Build a certification path to a trust anchor for the AC issuer; - Build a validated certification path to a trust anchor for the AC issuer; - Do revocation status checks on the certification path for the AC issuer; and Freeman, Housley, & Malpani [Page 13]
INTERNET DRAFT SCVP October 2004 - Do revocation status checks on the AC as well as the certification path for the AC issuer. For these purposes, the following OIDs are defined: id-stc OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 17 } id-stc-build-valid-pkc-path OBJECT IDENTIFIER ::= { id-stc 1 } id-stc-build-status-checked-pkc-path OBJECT IDENTIFIER ::= { id-stc 2 } id-stc-build-valid-aa-path OBJECT IDENTIFIER ::= { id-stc 4 } id-stc-build-status-checked-aa-path OBJECT IDENTIFIER ::= { id-stc 5 } 3.1.3 wantBack The wantBack item describes the kind of information the SCVP client wants from the SCVP server for the certificate(s) in the queriedCerts item. The wantBack item MUST contain a sequence of object identifiers (OIDs). Each OID tells the SCVP server what the client wants to know about the queriedCerts item. For each type of information specified in the request, the server MUST return information regarding its finding (in a successful response). For example, a request might include a checks item that only specifies certification path building and include a wantBack item that requests the return of the certification path built by the server. In this case, the response would not include a status for the validation of the certification path, but it would include a certification path that the server considers to be valid. A client that wants to perform its own certification path validation might use a request of this form. Alternatively, a request might include a checks item that requests the server to build a certification path and validate it, including revocation checking, and include a wantBack item that requests the return of the status. In this case, the response would include only a status for the validation of the certification path. A client that completely delegates certification path validation might use a request of this form. The wantBack item uses the WantBack type, which has the following syntax: WantBack ::= SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER For public key certificates, the types of information that can be requested are: - The certificate that was validated; Freeman, Housley, & Malpani [Page 14]
INTERNET DRAFT SCVP October 2004 - The certification path built for the certificate including the certificate that was validated; - Proof of revocation status for each certificate in the certification path; - Status indication; and - The public key from the certificate. For attribute certificates, the types of information that can be requested are: - The attribute certificate that was validated; - The certification path built for the AC issuer certificate; - Proof of revocation status for each certificate in the AC issuer certification path; - Proof of revocation status for the attribute certificate; and - Status indication. The client can also request a non-cached response to the request by including wantback id-swb-non-cached-resp in the request. For these purposes, the following OIDs are defined: id-swb OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 18 } id-swb-pkc-best-cert-path OBJECT IDENTIFIER ::= { id-swb 1 } id-swb-pkc-revocation-info OBJECT IDENTIFIER ::= { id-swb 2 } id-swb-pkc-cert-status OBJECT IDENTIFIER ::= { id-swb 3 } id-swb-pkc-public-key-info OBJECT IDENTIFIER ::= { id-swb 4 } id-swb-aa-cert-path OBJECT IDENTIFIER ::= { id-swb 5 } id-swb-aa-revocation-info OBJECT IDENTIFIER ::= { id-swb 6 } id-swb-ac-revocation-info OBJECT IDENTIFIER ::= { id-swb 7 } id-swb-ac-cert-status OBJECT IDENTIFIER ::= { id-swb 8 } id-swb-non-cached-resp OBJECT IDENTIFIER ::= { id-swb 9 } id-swb-pkc-cert OBJECT IDENTIFIER ::= { id-swb 10} id-swb-ac-cert OBJECT IDENTIFIER ::= { id-swb 11} id-swb-pkc-all-valid-cert-paths OBJECT IDENTIFIER ::= { id-swb 13} 3.1.4 validationPolicy The validationPolicy item, defines the validation policy The validationPolicy item defines the validation policy that the client wants the SCVP server to use during certificate validation. If Freeman, Housley, & Malpani [Page 15]
INTERNET DRAFT SCVP October 2004 this policy cannot be used for any reason, then the server MUST return an error response. The client and server can optionally agree on a set of parameters which may fully or partially define a validation policy. If the policy defines all parameters necessary for processing an SCVP request, then the client need only supply a reference to the policy in this item. If a partial set of parameters has been agreed upon, then the client supplies a reference to the policy plus whatever parameters are necessary to complete the request in this item. The syntax of the validationPolicy item is: ValidationPolicy ::= SEQUENCE { validationPolRef ValidationPolRef, validationAlg [0] ValidationAlg OPTIONAL, userPolicySet [1] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL, inhibitPolicyMapping [2] BOOLEAN OPTIONAL, requireExplicitPolicy [3] BOOLEAN OPTIONAL, inhibitAnyPolicy [4] BOOLEAN OPTIONAL, isCA [5] BOOLEAN OPTIONAL, trustAnchors [6] TrustAnchors OPTIONAL, keyUsages [7] SEQUENCE SIZE (1..MAX) OF KeyUsage OPTIONAL, extendedKeyUsages [8] ExtKeyUsageSyntax OPTIONAL} The validationPolRef item is required, but the remainder of the items are optional. The optional items are used to provide validation policy parameters. When the validation policy has no parameters, all of the optional items are absent. The validationAlg item specifies the validation algorithm. The userPolicySet item provides an acceptable set of certificate policies. The inhibitPolicyMapping item inhibits certificate policy mapping during certification path validation. The requireExplicitPolicy item requires at least one valid certificate policy in the certificate policies extension. The inhibitAnyPolicy item indicates whether the any-policy certificate policy OID is processed or ignored when evaluating certificate policy. The isCA item indicates whether the client expects the certificate subject to be a CA. The trustAnchors item indicates the trust anchors that are acceptable to the client. The keyUsages item indicates the technical usage of the public key that is to be confirmed by the server as acceptable. The extendedKeyUsages item indicates the application-specific usage of the public key that is to be confirmed by the server as acceptable. The syntax and semantics of each of these items is discussed in the following sections. 3.1.4.1 validationPolRef Freeman, Housley, & Malpani [Page 16]
INTERNET DRAFT SCVP October 2004 The reference to the validation policy can be either an OID or a URI. In either case, the client and server have agreed that the value represents a particular validation policy. The URI can point to a human readable definition of the policy to facilitate correct configuration. - serverContextInfo; and - the client's signature on the request. The syntax of the ValidationPolRef item is: ValidationPolRef::= CHOICE { valPolRefByOID [0] OBJECT IDENTIFIER, valPolRefByURI [1] IA5String} SCVP servers SHOULD support serverContextInfo. SCVP clients MAY support serverContextInfo 3.1.5 validationAlg The validationAlg item, defines the validation algorithm to be used by the SCVP server during certificate validation. The value of this item can be determined by agreement between the client and the server, and is represented as an object identifier. The server might want to assign additional object identifiers that indicate that some settings are used in addition to others given in the request. In this way, the validation algorithm object identifier can be a shorthand for some SCVP options, but not others. The validationAlg item uses the ValidationAlg type, which has the following syntax: ValidationAlg ::= SEQUENCE { valAlgId OBJECT IDENTIFIER, parameters ANY DEFINED BY valAlgId OPTIONAL } 3.1.5.1 Default Validation Algorithm The client can request the SCVP server's default validation policy or another validation policy. The object identifier to identify the default validation policy is: id-svp OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 19 } id-svp-defaultValPolicy OBJECT IDENTIFIER ::= { id-svp 1 } The default validation policy MUST use the basic validation algorithm (see section 3.1.5.2.1). Freeman, Housley, & Malpani [Page 17]
INTERNET DRAFT SCVP October 2004 When using the default validation policy, the client can override any of the default parameter values by supplying a specific value in the request. The SCVP server MUST make use of the provided parameter values or return an error response. All SCVP servers MUST support the default policy, but local policy MAY require the server to send an error response to all requests using the default policy. Neither the clients nor server MUST dereference the URI during SCVP request processing. The URI is simply used as a reference for the validation policy. Clients and server MAY dereference the URI as part of configuration. The syntax of the validationPolRef is: ValidationPolRef ::= CHOICE { valPolRefByOID [0] OBJECT IDENTIFIER, valPolRefByURI [1] IA5String } If there are any conflicts between the non-default policy referenced in the request and any supplied parameter values in the request, then the server MUST return an error response. 3.1.5.2 validationAlg The optional validationAlg item defines the validation algorithm to be used by the SCVP server during certificate validation. The value of this item can be determined by agreement between the client and the server, and the validation algorithm is represented by an object identifier. The syntax of the validationAlg is: ValidationAlg ::= SEQUENCE { valAlgId OBJECT IDENTIFIER, parameters ANY DEFINED BY valAlgId OPTIONAL } The following section specifies the basic validation algorithm and the name validation algorithm. SCVP clients and servers MUST support both validation algorithms defined in this section. Other validation algorithms can be specified in other documents for use with specific applications. SCVP clients and servers MAY support any such validation algorithms. 3.1.5.2.1 Basic Validation Algorithm The client can request use of the SCVP basic validation algorithm or another algorithm. The basic validation algorithm implements the full certification path validation algorithm as defined in Freeman, Housley, & Malpani [Page 18]
INTERNET DRAFT SCVP October 2004 section 6 of [PKIX-1]. Other validation algorithms MAY implement functions over and above those in the basic algorithm, but validation algorithms MUST generate results compliant with the basic validation algorithm. That is, none of the validation requirements in the basic algorithm can be omitted from any newly defined validation algorithms. However, other validation algorithms MAY reject paths which are valid using the basic validation algorithm. The object identifier to identify the basic validation algorithm is: id-svp-basicValAlg OBJECT IDENTIFIER ::= { id-svp 3 } When id-svp-basicValAlg appears as in valAlgId, the parameters item MUST be absent. The meaning of the default validation algorithm is: - Trust anchors will come from the trustAnchors item. If no certificates are specified in the trustAnchors item, then the SCVP server will use trust anchors of its own choosing. - The acceptable policy set will come from the userPolicySet item. If no certificate policies are specified in the userPolicySet item, then the SCVP server will use any-policy. - The SCVP server will check for certificate revocation using CRLs, delta CRLs, OCSP responses, or any other source of revocation information that is available. 3.1.5.2.2 Basic Validation Algorithm Errors The following errors are defined for the basic validation algorithm: id-bvae OBJECT IDENTIFIER ::= id-svp-basicValAlg id-bvae-expired OBJECT IDENTIFIER ::= { id-bvae 1 } id-bvae-notYetValid OBJECT IDENTIFIER ::= { id-bvae 2 } id-bvae-wrong-Anchor OBJECT IDENTIFIER ::= { id-bvae 3 } id-bvae-partial-chain OBJECT IDENTIFIER ::= { id-bvae 4 } id-bvae-invalid-Key-Usage OBJECT IDENTIFIER ::= { id-bvae 10 } id-bvae-invalid-Purpose OBJECT IDENTIFIER ::= { id-bvae 11 } id-bvae-invalid-Policy OBJECT IDENTIFIER ::= { id-bvae 12 } id-bvae-invalid-Name OBJECT IDENTIFIER ::= { id-bvae 13 } id-bvae-invalid-Entity OBJECT IDENTIFIER ::= { id-bvae 14 } id-bvae-invalid-Depth OBJECT IDENTIFIER ::= { id-bvae 15 } The id-bvae-expired value means that the validation time used for the request was later than the notAfter time in the certificate. Freeman, Housley, & Malpani [Page 19]
INTERNET DRAFT SCVP October 2004 The id-bvae-notYetValid value means that the validation time used for the request was before the notBefore time in the certificate. The id-bvae-wrong-Anchor value means that a certification path was able to be constructed but that the trust anchor for the path was not one of the trust anchors required. The id-bvae-partial-chain value means that a certification path was unable to be constructed to any trust anchor. The id-bvae-invalid-Key-Usage value means that one of the certificates in the certification path has the wrong key usage(PKIX-1 section 4.2.1.3). The key in a CA certificate can verify a certificate, but the key usage in the certificate does not contain the cert sign bit. The id-bvae-invalidPurpose value means that one of the certificates in the certification path has the wrong purpose (PKIX-1 section 4.2.1.13). The id-bvae-invalidCertPolicy value means that some part of certificate policy evaluation has failed. For example, the requested policy was not valid in the certificate or the request explicit policy is true and there are no valid certificate polices. The id-bvae-invalidName value means that one of the names in one of the certificates in the certification path violates a name constraints extension in a parent certificate. The id-bvae-invalidEntity value means that one of the entity types in the certification pathas defined in the basic constraints extension is invalid. That is, an end entity has signed a certificate. The id-bvae-invalidPathDepth value means that the certification path length violates the path length constraints in the basic constraints extension. 3.1.5.2.3 Name Validation Algorithm The name validation algorithm allows the client to supply an application identifier and a name to the server. The application identifier defines the name matching rules to use in comparing the name supplied in the request with the names in the certificate. id-svp-NameValAlg OBJECT IDENTIFIER ::= { id-svp 2 } id-svp-dnValAlg OBJECT IDENTIFIER ::= { id-svp 4 } When the id-svp-NameValAlg appears as a valAlgId, the parameters MUST use the NameValidationAlgParms syntax: Freeman, Housley, & Malpani [Page 20]
INTERNET DRAFT SCVP October 2004 NameValidationAlgParms ::= SEQUENCE { keyPurposeId KeyPurposeId, validationNames GeneralNames } KeyPurposeId and GeneralNames are defined in [PKIX-1]. If more than one name is supplied in the validationNames value, all names MUST be of the same type and be valid according to the name matching rules associated with the KeyPurposeId. If the keyPurposeID supplied in the request is id-svp-dnValAlg, then GeneralNames supplied in the request MUST be a DN name, and the matching rules to be used are defined in [PKIX-1]. If the keyPurposeID supplied in the request is id-kp-serverAuth [PKIX-1], then GeneralNames supplied in the request MUST be a DNS name, and the matching rules to be used are defined in [HTTP-TLS]. If the keyPurposeID supplied in the request is id-kp-mailProtection [PKIX-1], then GeneralNames supplied in the request MUST be a rfc822Name, and the matching rules are defined in [SMIME-CERT]. SCVP server MUST support the name validation algorithms for id-svp- dnValAlg, id-kp-serverAuth, id-kp-mailProtection. SCVP server may suport other name validation algorithms. 3.1.5.2.4 Name Validation Algorithm Errors The following errors are defined for the Name Validation Algorithm id-nvae OBJECT IDENTIFIER ::= id-svp-NameValAlg id-nvae-name-mismatch OBJECT IDENTIFIER ::= { id-nvae 1 } id-nvae-no-name OBJECT IDENTIFIER ::= { id-nvae 2 } id-nvae-unknown-pupose OBJECT IDENTIFIER ::= { id-nvae 3 } id-nvae-bad-name OBJECT IDENTIFIER ::= { id-nvae 4 } id-nvae-bad-name-type OBJECT IDENTIFIER ::= { id-nvae 5 } id-nvae-mixed-names OBJECT IDENTIFIER ::= { id-nvae 6 } The id-nvae-nameMismatch value means the client supplied a name with the validation policy, which the server recognized and the server found corresponding name type in the certificate, but was unable to find a match to the name supplied. For example, the client supplied a DNS name of example1.com, the certificate contained a DNS name of example.com. The id-nvae-noCertName value means the client supplied a name with the validation policy, which the server recognized, but the server could not find the corresponding name type in the certificate. For Freeman, Housley, & Malpani [Page 21]
INTERNET DRAFT SCVP October 2004 example, the client supplied a DNS name of example1.com, the certificate only contained a rfc822Name of user@example.com. The id-nvae-unknownPupose value means the client supplied KeyPurposeID which the server does not recognize. The id-nvae-badName value means the client supplied either and empty or malformed name in the request. The id-nvae-badNameType value means the client supplied an inappropriate name type for the key purpose. For example, the client specified a key purpose ID of id-kp-serverAuth, and a rfc822 name of user@example.com. The id-nvae-mixedNames value means the client supplied multiple names in the request of different types. The userPolicySet item specifies a list of policy identifiers that the SCVP server MUST use when forming and validating a certificate If certPolicies is not specified, then any-policy MUST be used. 3.1.5.3 userPolicySet The userPolicySet item specifies a list of certificate policy identifiers that the SCVP server MUST use when constructing and validating a certification path. If userPolicySet is not specified, then any-policy MUST be used. SCVP clients SHOULD support userPolicySet item in requests, and SCVP servers MUST support userPolicySet item in requests. 3.1.5.4 inhibitPolicyMapping The inihibitPolicyMapping specifies an input to the certification path validation algorithm, and it controls whether policy mapping is allowed in the certification path validation (see [PKIX-1], section 6.1.1). By default the server allows policy mapping as part of certification path validation. If the client wants the server to inhibit policy mapping, inhibitPolicyMapping is set to TRUE in the request. SCVP clients and servers MUST support the default behavior. SCVP clients MAY support inhibiting policy mapping. SCVP servers SHOULD support inhibiting policy mapping. 3.1.5.5 requireExplicitPolicy The requireExplicitPolicy specifies an input to the certification path validation algorithm, and it controls whether there must be at least one valid policy in the certificate policies extension (see [PKIX], section 6.1.1). By default the server accepts no policies Freeman, Housley, & Malpani [Page 22]
INTERNET DRAFT SCVP October 2004 in the certificate policies extension of valid certificates. If the client wants the server to require at least one policy, requireExplicitPolicy is set to TRUE in the request. SCVP clients and servers MUST support the default behavior. SCVP clients MAY support requiring explicit policies. SCVP server SHOULD support requiring explicit policies. 3.1.5.6 inhibitAnyPolicy The inhibitAnyPolicy specifies an input to the certification path validation algorithm (see [PKIX], section 6.1.1), and it controls whether the any-policy OID is processed or ignored when evaluating certificate policy. By default the server processes the any-policy OID. If the client wants the server to ignore the any-policy OID, inhibitAnyPolicy MUST be set to TRUE in the request. If the value is absent in the request or the value is set to FALSE, the server MUST process the any-policy OID. SCVP clients and servers MUST support the default behavior. SCVP clients MAY support ignoring the any-policy OID. SCVP servers SHOULD support ignoring the any-policy OID. 3.1.5.7 isCA The isCA specifies whether the client expects the certificate subject to be a CA. This corresponds to CA BOOLEAN value in the basic constraints extension [PKIX-1, 4.2.1.10]. If the client requires the entity type of certificate being validated to be a CA, then it MUST set the value of isCA to be TRUE in the request. If the client requires the subject to be an end entity, then it MUST set the value to FALSE. If the client does not care about the entity type, then it MUST omit the BOOLEAN value. If the BOOLEAN value is omitted from the request and the client submits a CA certificate as the subject of the validation request, then a server MUST NOT treat this as an error. SCVP client and server MUST support the default behavior. SCVP client SHOULD support setting the BOOLEAN value to TRUE, and the SVCP client MAY support setting the BOOLEAN value to FALSE. SCVP server MUST support the isCA BOOLEAN being set to either TRUE or FALSE. 3.1.5.8 trustAnchors Freeman, Housley, & Malpani [Page 23]
INTERNET DRAFT SCVP October 2004 The trustAnchors item specifies the trust anchors at which the certification path must terminate in if the path is to be considered valid by the SCVP server for the request. If a trustAnchors item is present, the server MUST NOT consider any certification paths ending in other trust anchors as valid. The TrustAnchors type contains one or more trust anchor specification. A certificate reference can be used to identify the trust anchor by certificate hash and optionally a distinguished name with serial number. Alternatively, trust anchors can be provided directly. The order of trust anchor specifications within the sequence is not important. Any CA certificate which meets the requirements of [PKIX-1] for signing certificates can be provided as a trust anchor. If a trust anchor is supplied which does not meet these requirements, the server MUST return an error response. The trust anchor itself, regardless of its form, MUST NOT be included in any certification path returned by the SCVP server. TrustAnchors has the following syntax: TrustAnchors ::= SEQUENCE SIZE (1..MAX) OF PKCReference SCVP server MUST support TrustAnchors. SCVP clients SHOULD support trust anchors. 3.1.5.9 keyUsages The key usage extension [PKIX-1, section 4.2.1.3] in the certificate defines the technical purpose (such as encipherment, signature, and certificate signing) of the key contained in the certificate. If the client wishes to confirm the technical usage, then they can communicate the usage they want to validate by the same structure using the same semantics as defined in [PKIX-1]. Therefore, if the client obtained the certificate in the context of a digital signature, they can confirm this use by including a keyUsage structure with the digital signature bit set. The keyUsages item can contain one or more keyUsage definitions to allow the client to search for a set of patterns any one of which is acceptable to the client. If the client whishes to match against multiple possibilities that the client pass in a sequence of possible patterns. Each keyUasge can contain a set of one or more bits set in the request, all bits MUST be present in the certificate to match against an instance of the keyUsage in the SCVP request. If the certificate key usage extension contains more usages than requested, then the certificate MUST be considered a match. Therefore if a client whishes to check for either digital signature or non-repudiation, then the client provides two keyUsage values, one with digital signature set, and the other with non- repudiation set. If the key usage extension is absent from the Freeman, Housley, & Malpani [Page 24]
INTERNET DRAFT SCVP October 2004 certificate, the certificate MUST be considered good for all usages therefore any pattern in the SCVP request will match. SCVP clients SHOULD support keyUsages, and SCVP servers MUST support keyUsages. 3.1.5.10 extendedKeyUsages The extended key usage extension [PKIX-1, section 4.2.1.13] defines more abstract technical purposes in addition to or in place of the purposes indicated in the key usage extension for which the certified public key may be used. If the client wishes to confirm the extended key usage, then they can communicate the usage they want to validate by the same extension using the same semantics as defined in [PKIX-1]. Therefore if the client obtained the certificate in the context of a TLS server, they can confirm this usage by including the extended key usage structure with the id-kp- serverAuth object identifier. If more than one usage is set in the request, all usages MUST be present in the certificate. If the certificate extension contains more usages than requested, then the certificate MUST be considered a match. SCVP clients SHOULD support extendedKeyUsages, and SCVP servers MUST support extendedKeyUsages. 3.1.6 responseFlags The optional response flags item allows the client to indicate which optional features in the CVResponse it wants the server to include. If the default values for all of the flags are used, then the response flags item MUST NOT be included in the request. The syntax of the responseFlags is: ResponseFlags ::= SEQUENCE { responseRefHash BOOLEAN DEFAULT TRUE, responseValidationPolByRef BOOLEAN DEFAULT TRUE, signResponse BOOLEAN DEFAULT TRUE } Each of the response flags is described in the following sections. 3.1.6.1 responseRefHash The responseRefHash controls how the server identifies the request to which it is responding. By default, the server includes a hash of the request in the response. If the client wants the server to include the full request in the response, responseRefHash is set to FALSE. The main reason a client would request the server to include the full request in the response is to archive the request- response exchange in a single object. That is, the client wants to archive a single object which includes both request and response. Freeman, Housley, & Malpani [Page 25]
INTERNET DRAFT SCVP October 2004 SCVP clients and servers MUST support the default behavior. SCVP clients MAY support requesting and processing the full request. SCVP servers SHOULD support returning the full request. 3.1.6.2 responseValidationPolByRef The responseValidationPolByRef controls whether the response includes by reference or by value the validation policy used to process the request. By default the response will contain references to the validation policy. If the client wants the validation policy to be included by value, then the responseValidationPolByRef is set to FALSE. The main reason a client would request the server to include validation policy to be included by value is to archive the request-response exchange in a single object. That is, the client wants to archive the CVResponse and have it include every aspect of the validation policy. SCVP clients and servers MUST support the default behavior. SCVP clients MAY support requesting and processing the responseValidationPolByRef. SVCP server SHOULD support returning the responseValidationPolByRef. 3.1.6.3 signResponse The signResponse indicates whether the client requires the server to sign the response. If the client is performing full certification path validation on the response and it is not concerned about the source of the response, then the client does not benefit from a signature on the response. In this case, the client can indicate to the server that a signature is unnecessary. However, the server is always permitted to return a signed response. SCVP clients that support delegated path discovery (DPD) as defined in [RQMTS] MUST support setting this value to FALSE. SCVP clients that support delegated path validation (DPV) as defined in [RQMTS] require a signed response. Such clients MUST always set this value to TRUE or accept the default behavior, which requires the server to return a signed response. SCVP servers MUST support returning signed responses, and SCVP servers SHOULD support returning unsigned responses. Based on local policy, the server can be configured return signed or unsigned responses if this value is set to FALSE. 3.1.7 serverContextInfo The optional serverContextInfo item, if present, contains context from a previous request-response exchange with the same SCVP server. It allows the server to return more than one certification path for Freeman, Housley, & Malpani [Page 26]
INTERNET DRAFT SCVP October 2004 the same certificate to the client. For example, if a server constructs a particular certification path for a certificate, but the client finds it unacceptable, the client can then send the same query back to the server with the serverContextInfo from the first response, and the server will be able to provide a different certification path (if another one can be found). Contents of the serverContextInfo are opaque to the SCVP client. That is, the client only knows that it needs to return the value provided by the server with the subsequent request to get a different certification path. Note that the subsequent query needs be essentially identical to the previous query. The client MUST NOT change any items other than: - requestNonce; - serverContextInfo; and - the client's signature on the request. SCVP clients MAY support serverContextInfo, and SCVP servers SHOULD support serverContextInfo. 3.1.8 valididationTime The optional validationTime item, if present, tells the date and time relative to which the SCVP client wants the server to perform the checks. If the validationTime is not present, the server MUST perform the validation using the date and time at which the server processes the request. If the validationTime is present, it MUST be encoded as GeneralizedTime. The validationTime provided MUST be a retrospective time since the server can only perform a validity check using the current time (default) or previous time. A Server can ignore the validationTime provided in the request if the time is within the clock skew of the servers current time. GeneralizedTime values MUST be expressed Universal Coordinated Time (UTC) (which is also known as Greenwich Mean Time and Zulu time) and MUST include seconds (i.e., times are YYYYMMDDHHMMSSZ), even when the number of seconds is zero. GeneralizedTime values MUST NOT include fractional seconds. The information in the corresponding CertReply item in the response MUST be formatted as if the server created the response at the time indicated in the validationTime. However, if the server does not have appropriate historical information, the server MUST return an error response. SCVP servers MUST apply a clock skew to the validity time to allow for minor time synchronization errors. The default value is 10 Freeman, Housley, & Malpani [Page 27]
INTERNET DRAFT SCVP October 2004 minutes. If the server uses a value other than the default it MUST include the clock skew value in the validation policy response. SCVP clients MAY support validationTime other than the current time. SCVP servers MUST support using its current time, and SHOULD support the client setting the validationTime in the request. 3.1.9 intermediateCerts The optional intermediateCerts item helps the SCVP server create valid certification paths. The intermediateCerts item, when present, provides certificates that the server MAY use when forming a certification path. The certificates in the intermediateCerts item MAY be used by the server in addition to any other certificates that the server can access when building certification paths. When present, the intermediateCerts item MUST contain at least one certificate, and the intermediateCerts item MUST be structured as a CertBundle. The certificates in the intermediateCerts MUST NOT be considered as valid by the server just because they are present in this item. The CertBundle type contains one or more certificate references. The order of the entries in the bundle is not important. CertBundle has the following syntax: CertBundle ::= SEQUENCE SIZE (1..MAX) OF Certificate SCVP clients SHOULD support intermediateCerts, and SCVP servers MUST support intermediateCerts. 3.1.10 revInfos The optional revInfo item specifies revocation information such as CRLs, delta CRLs [PKIX-1], and OCSP responses [OCSP] that the SCVP server MAY use this information when validating certification paths. The purpose of the revInfos item is to provide revocation information to which the server might not otherwise have access, such as an OCSP response that the client received along with the certificate. Note that the information in the revInfos item might not be used by the server. For example, the revocation information might be associated with certificates that the server does not use in the certification path that it constructs. Clients SHOULD be courteous to the SCVP server by separating CRLs and delta CRLs. However, since the two share a common syntax, SCVP servers SHOULD accept delta CRLs even if they are identified as regular CRLs by the SCVP client. CRLs, delta CRLs, and OCSP responses can be provided as revocation information. If needed, additional object identifiers can be assigned for additional revocation information types in the future. Freeman, Housley, & Malpani [Page 28]
INTERNET DRAFT SCVP October 2004 The revInfos item uses the RevocationInfos type, which has the following syntax: RevocationInfos ::= SEQUENCE SIZE (1..MAX) OF RevocationInfo RevocationInfo ::= CHOICE { crl [0] CertificateList, delta-crl [1] CertificateList, ocsp [2] OCSPResponse, other [3] OtherRevInfo } OtherRevInfo ::= SEQUENCE { riType OBJECT IDENTIFIER, riValue ANY DEFINED BY riType } 3.1.11 producedAt The client MAY allow the server to use a cached SCVP response. When doing so, the client uses the producedAt item to express requirements on the freshness of the cached response. The producedAt item tells the earliest date and time at which an acceptable cached response could have been produced. The producedAt item represents the date and time in UTC, using the GeneralizedTime type. The value in the producedAt item is independent of the validation time. GeneralizedTime value MUST be expressed in UTC, as defined in section 3.1.8. SCVP client MAY support using producedAt values in the request. SCVP server SHOULD support the producedAt values in the request. 3.1.12 queryExtensions The optional queryExtensions item contains Extensions. If present, each extension in the sequence extends the query. This specification does not define any extensions, the facility is provided to allow future specifications to extend SCVP. The syntax for extensions is imported from [PKIX-1]. The queryExtensions item, when present, MUST contain a sequence of extension items, and each of extension MUST contain extnID, critical, and extnValue items. Each of these is described in the following sections. 3.1.12.1 extnID The extnID item is an identifier for the extension. It contains the object identifier that names the extension. 3.1.12.2 critical Freeman, Housley, & Malpani [Page 29]
INTERNET DRAFT SCVP October 2004 The critical item is a BOOLEAN. Each extension is designated as either critical (with a value of TRUE) or non-critical (with a value of FALSE). By default, the extension is non-critical. An SCVP server MUST reject the query if it encounters a critical extension that it does not recognize; however, a non-critical extension MAY be ignored if it is not recognized. 3.1.12.3 extnValue The extnValue item is an octet string, which contains the extension value. An ASN.1 type is specified for each extension, identified by the associated extnID object identifier. 3.2 requestorRef The optional requestorRef item is a local reference to the client, and it is intended for use in environments where SCVP relay is employed. As described in [REQMTS], some network environments a SCVP server might not be able to obtain all of the information that it needs to process a request. However, the SCVP server might be configured to use the services of one or more other SCVP servers to fulfill all requests. In such cases, the client is unaware that the queried SCVP server is using the services of other SCVP servers, and the client-queried SCVP server acts as a SCVP client to another SCVP server. Unlike the original client, the SCVP server is expected to have moderate computing and memory resources, enabling the use of relay, re-direct or multicasting mechanisms. The requestorRef item is needed by SCVP servers that act as client to other SCVP servers in order to match a response to the original request which triggered it. The requestorRef item is also needed to prevent looping in some configurations. The value is of local significance to the client, and the server MUST threat this as an opaque value. To detect loops, the server MUST inspect the sequence of octet strings, looking for values that it inserted as a client. If the SCVP client includes a requestorRef value in the request, then the SCVP server MUST return the same value in a non-cached response. The SCVP server MAY omit the requestorRef value from cached SCVP responses. The requestorRef item MUST be an octet string. No provisions are made to ensure uniqueness of the requestorRef octet string; however, all of the octets MUST have values other than zero. 3.3 requestNonce The optional requestNonce item contains a request identifier generated by the SCVP client. If the client includes a requestNonce value in the request, it is expressing a preference the SCVP server SHOULD return a non-cached response. If the server Freeman, Housley, & Malpani [Page 30]
INTERNET DRAFT SCVP October 2004 returns a non-cached response it MUST include the requestNonce from the request in the response; however, the server MAY return a cached success response which MUST NOT have a requestNonce. If the client includes a requestNonce and also sets a wantBack of id-swb- nonCachedRespRequired, the client is indicating that the SCVP server MUST return either a non-cached response including the requestNonce or an error response. The client SHOULD include a requestNonce item in every request to prevent an attacker from acting as a man-in-the-middle by replaying old responses from the server. The requestNonce value SHOULD change with every request sent by the client. The client MUST NOT include the wantBack of id-swb-nonCachedRespRequired without a requestNonce, and a server receiving such a request SHOULD return an invalidRequest error response. The requestNonce item, if present, MUST be an octet string that was generated exclusively for this request. 3.4 requestExtensions The OPTIONAL requestExtensions item contains Extensions. If present, each Extension in the sequence extends the request. This specification does not define any extensions, the facility is provided to allow future specifications to extend the SCVP. The syntax for Extensions is imported from [PKIX-1]. The requestExtensionscvRequestExtensions item, when present, MUST contain a sequence of extension items, and each of extension MUST contain extnID, critical, and extnValue items. Each of these is described in the following sections. 3.4.1 extnID The extnID item is an identifier for the extension. It contains the object identifier that names the extension. 3.4.2 critical The critical item is a BOOLEAN. Each extension is designated as either critical (with a value of TRUE) or non-critical (with a value of FALSE). By default, the extension is non-critical. An SCVP server MUST reject the query if it encounters a critical extension it does not recognize. A non-critical extension MAY be ignored if it is not recognized, but MUST be processed if it is recognized. 3.4.3 extnValue The extnValue item contains an octet string. Within the octet string is the extension value. An ASN.1 type is specified for each extension, identified by the associated extnID object identifier. Freeman, Housley, & Malpani [Page 31]
INTERNET DRAFT SCVP October 2004 3.5 dhPublicKey The dhPublicKey item is an optional Diffie-Hellamn public value. It is defined in PKIX-ALGS. When used in conjunction with the servers Diffie-Hellamn value it allows the client and server to compute a shared secret which can be used to integrity protect the SCVP request-response pair. If the client is not using a protected transport such as TLS, an does not have another mechanism to integrity protect the request-response pair such as a Kerberos session key or a signing public key, then the client SHOULD generate a DH key with the same parameters as the servers (see section Error! Reference source not found.) and use this to generate the shared secret with the servers public values and submit an authenticatedData request using the calculated shared secret for the HMAC secret. For the server to compute the shared secret, it must lean the public values the client generates, therefore the client MUST include this in the request if it uses this mechanism to integrity protect the request-response pair. The reuse by the client of the generated DH key across multiple requests is a matter of local policy. 3.6 SCVP Request Authentication It is a matter of local policy what validation policy is used by the server when validating requests. When validating signed SCVP requests, the SCVP servers SHOULD use the validation algorithm defined in section 6 of PKIX-1. If the certificate used to validate a SignedData validation request includes the key usage extension [PKIX-1, section 4.2.1.3], it MUST have either the digital signature bit set, the non-repudiation bit set, or both bits set. If the certificate used to validate an AuthenticatedData validation request includes the key usage extension, it MUST have the key agreement bit set. If the certificates used on a validation request contains the extended Key Usage extension [PKIX-1, section 4.2.1.13], it is a matter of local policy which OID, if any, the server will check in the extension. The SCVP server MAY require the following OID id-kp OBJECT IDENTIFIER ::= { id-pkix 3 } id-kp-scvpClient OBJECT IDENTIFIER ::= { id-kp 16 } If a signed request fails to meet the validation policy of the server, it MUST be treated as an unauthenticated request. 4 Validation Response Freeman, Housley, & Malpani [Page 32]
INTERNET DRAFT SCVP October 2004 A SCVP server response to the client MUST be a single CVResponse item. When a CVResponse is encapsulated in a MIME body part, application/cv-response MUST be used. There are a number of forms of an SCVP response: 1. A success response to a request made over a protected transport such as TLS. These responses SHOULD be unsigned by the server 2. A success response to a request that has SignResponse set to FALSE. These responses SHOULD be unsigned by the server. 3. All other success responses MUST be signed by the server. If the server is unable to return a signed success response due to local policy, then it MUST return an error response. 4. A error response to a request made over a protected transport such as TLS. These responses SHOULD be unsigned by the server 5. A error response to a request that has SignResponse set to FALSE. These responses SHOULD be unsigned by the server. 6. An error response to an authenticated request. These responses MUST be signed by the server. 7. An error response to an authenticatedData HMAC request where HMAC is valid. These responses MUST be signed by the server. 8. All other error responses MUST NOT be signed by the server. Successful responses are be made when the server has fully complied with the request. That is, the server was able to build a certification path using the referenced or supplied validation policy, and it was able to comply with all the requested parameters. If the server is unable to build a certification path using the required validation policy or the request contains an unsupported option, then the server MUST return an error response. For signed requests and responses, SCVP servers MUST support SignedData, and AuthenticatedData. It is a matter of local policy which types are used. If the server is making a signed response to a signed request, then the server MUST use the same signature type (SignedData or AuthenticatedData) as in the request. An overview of the structure used for an unsigned response is provided below. Many details are not shown, but the way that SCVP makes use of CMS is clearly illustrated. Freeman, Housley, & Malpani [Page 33]
INTERNET DRAFT SCVP October 2004 ContentInfo { contentType id-ct-scvp-certValResponse, -- (1.2.840.113549.1.9.16.1.11) content CVResponse } The signed response consists of a CVResponse encapsulated in either a SignedData or an AuthenticatedData which is in turn encapsulated in a ContentInfo. An overview of the structure used for a signed response is provided below. As above, many details are not shown, but the way that SCVP makes use of CMS is clearly illustrated. SignedData Example: ContentInfo { contentType id-signedData, -- (1.2.840.113549.1.7.2) content SignedData } SignedData { version CMSVersion, digestAlgorithms DigestAlgorithmIdentifiers, encapContentInfo EncapsulatedContentInfo, certificates [0] IMPLICIT CertificateSet OPTIONAL, -- MUST include server cert crls [1] IMPLICIT CertificateRevocationLists OPTIONAL, signerInfos SET OF SignerInfos } -- Only one in SCVP SignerInfo { version CMSVersion, sid SignerIdentifier, digestAlgorithm DigestAlgorithmIdentifier, signedAttrs SignedAttributes, -- Required by CMS signatureAlgorithm SignatureAlgorithmIdentifier, signature SignatureValue, unsignedAttrs UnsignedAttributes } -- Not used in SCVP EncapsulatedContentInfo { eContentType id-ct-scvp-psResponse, -- (1.2.840.113549.1.9.16.1.11) eContent OCTET STRING } -- Contains CVResponse AuthenticatedData Example: ContentInfo { contentType id-ct-authData, -- (1.2.840.113549.1.9.16.1.2) content AuthenticatedData } Freeman, Housley, & Malpani [Page 34]
INTERNET DRAFT SCVP October 2004 AuthenticatedData ::= SEQUENCE { version CMSVersion, originatorInfo OriginatorInfo, recipientInfos RecipientInfos, -- Only for SCVP client macAlgorithm MessageAuthenticationCodeAlgorithm, digestAlgorithm DigestAlgorithmIdentifier, encapContentInfo EncapsulatedContentInfo, authAttrs AuthAttributes, -- Required by CMS mac MessageAuthenticationCode, unauthAttrs UnauthAttributes } -- Not used in SCVP EncapsulatedContentInfo { eContentType id-ct-scvp-psResponse, -- (1.2.840.113549.1.9.16.1.11) eContent OCTET STRING } -- Contains CVResponse The SCVP server MUST include its own certificate in the certificates field within SignedData. Other certificates can also be included. The SCVP server MAY also provide one or more CRLs in the crls field within SignedData. The signedAttrs within SignerInfo MUST include the content-type and message-digest attributes defined in [CMS], and it SHOULD include the signing-certificate attribute as defined in [ESS]. Within the signing-certificate attribute, the first certificate identified in the sequence of certificate identifiers MUST be the certificate of the SCVP server. The inclusion of other certificate identifiers in the signing-certificate attribute is OPTIONAL. The inclusion of policies in the signing-certificate is OPTIONAL. The CVResponse item contains the server response. The CVResponse MUST contain the cvRespVersion, policyID, producedAt, and respStatus items. The CVResponse MAY also contain the respValidationPolicy, requestorRef, requestorName, responder, replyObjects, respNonce, serverContextInfo, and respExtensions optional items. The replyObjects item MUST contain exactly one CertReply item for each certificate requested. The requestorRef and the responder items MUST be included if the request included a requestor item. The respNonce item MUST be included if the request included a requestNonce item and a non-cached response is provided. The CVResponse MUST have the following syntax: CVResponse ::= SEQUENCE { cvResponseVersion cvResponseVersion INTEGER, policyID INTEGER, producedAt GeneralizedTime, Freeman, Housley, & Malpani [Page 35]
INTERNET DRAFT SCVP October 2004 responseStatus ResponseStatus, respValidationPolicy [0] RespValPolicy OPTIONAL, requestRef [1] RequestReference OPTIONAL, requestorRef [2] OCTET STRING OPTIONAL, requestorName [3] GeneralNames OPTIONAL, responder [4] OCTET STRING OPTIONAL, replyObjects [5] ReplyObjects OPTIONAL, respNonce [6] OCTET STRING OPTIONAL, serverContextInfo [7] OCTET STRING OPTIONAL, cvResponseExtensions [8] Extensions OPTIONAL } 4.1 cvResponseVersion The syntax and semantics of cvResponseVersion are the same as cvRequestVersion item is described in section 3.1. The cvResponseVersion MUST match the cvRequestVersion in the request. If the server cannot generate a response with a matching version number, then the server MUST return an error response that indicates the highest version number that the server supports as the version number. 4.2 policyID The policy ID used by the SCVP server when it processed the request. See section 6.4 for details. 4.3 producedAt The producedAt item tells the date and time at which the SCVP server generated the response. The producedAt item represents the date and time in UTC, using the GeneralizedTime type, and this value is independent of the validation time. GeneralizedTime value MUST be expressed in UTC, and it MUST be interpreted as defined in section 3.1.8. 4.4 responseStatus The responseStatus item gives status information to the SCVP client about its request. The responseStatus item has a numeric status code and an optional string that is a sequence of characters from the ISO/IEC 10646-1 character set encoded with the UTF-8 transformation format defined in [UTF8]. The string MAY be used to transmit status information. The client MAY choose to display the string to a human user. However, because there is often no way to know the languages understood by a human user, the string may be of little or no assistance. The responseStatus item uses the responseStatus type, which has the following syntax: Freeman, Housley, & Malpani [Page 36]
INTERNET DRAFT SCVP October 2004 ResponseStatus ::= SEQUENCE { statusCode CVStatusCode, errorMessage [0] UTF8String OPTIONAL } CVStatusCode ::= ENUMERATED { okay (0), skipUnrecognizedItems (1), tooBusy (10), invalidRequest (11), internalError (12), badStructure (20), unsupportedVersion (21), abortUnrecognizedItems (22), unrecognizedSigKey (23), badSignature (24), unableToDecode (25), notAuthorized (26), unsupportedChecks (27), unsupportedWantBacks (28), unsupportedSignature (29), invalidSignature (30), relayingLoop (40), unrecognizedValPol (50), unrecognizedValAlg (51), fullRequestRefUnsuported (52), fullPolResponseUnsuported (53), inhibitPolMapUnsuported (54), requireExpPolUnsuported (55), ignoreAnyPolUnsuported (56), validityTimeUnsuported (57), unrecognizedUserPolOID (60), unrecognizedValPolOID (61), unrecognizedValAlgOID (62), unrecognizedCritQueryExt (63), unrecognizedCritRequestExt (64)} The CVStatusCode values have the following meaning: 0 The request was fully processed. 1 The request included some unrecognized items; however, processing was able to continue ignoring them. 10 Too busy; try again later. 11 The server was able to decode the request, but there was some other problem with the request. 12 An internal server error occurred. 20 The structure of the request was wrong. 21 The version of request is not supported by this server. 22 The request included unrecognized items, and the server was not able to continue processing. 23 The key given in the RequestSignature is not recognized. Freeman, Housley, & Malpani [Page 37]
INTERNET DRAFT SCVP October 2004 24 The signature or message authentication code did not match the body of the request. 25 The encoding was not understood. 26 The request was not authorized. 27 The request included unsupported checks items, and the server was not able to continue processing. 28 The request included unsupported want back items, and the server was not able to continue processing. 29 The server does not support the signature or message authentication code algorithm used by the client to sign the request. 30 The server could not validate the client's signature or message authentication code on the request. 40 The request was previously relayed by the same server. 50 The request contained an unrecognized validation policy reference. 51 The request contained an unrecognized validation algorithm OID. 52 The server does not support returning the full request in the response. 53 The server does not support returning the full validation policy by value in the response. 54 The server does not support inhibiting policy mapping. 55 The server does not support requiring explicit policy. 56 The server does not support ignoring the any-policy certificate policy OID. 57 The server only validates requests using current time. 60 The certificate policy OID is not recognized. 61 The validation policy OID or URI is not recognized. 62 The validation algorithm OID is not recognized. 63 The query item in the request contains a critical extension whose OID is not recognized. 64 The request contains a critical request extension whose OID is not recognized. Status codes 0-9 are reserved for codes where the request was processed by the server and therefore MUST be sent in a success response. Status codes 10 and above indicate an error and MUST therefore be sent in an unsigned error response. 4.5 respValidationPolicy The respValidationPolicy item contains either a reference to the full validation policy or the full policy by value used by the server to validate the request. It MUST be present in success responses and MUST NOT be present in error responses. The choice between retuning either the policy by reference or by value is controlled by the fullPolicyResponse. The resultant validation policy is the union of the following: Freeman, Housley, & Malpani [Page 38]
INTERNET DRAFT SCVP October 2004 1. Values from the validation policy specified by reference in the request. 2.. Values from the request. 3. Default values used by the server for any parameter not specified by 1 or 2. The respValidationPolicy syntax is: RespValidationPolicy ::= SEQUENCE { validationPolRef ValidationPolRef, validationPolValues [0] ValidationPolValues OPTIONAL, userFinalPolicySet [1] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL, permittedSubtrees [2] SEQUENCE SIZE (1..MAX) OF GeneralNames OPTIONAL, excludedSubtrees [3] SEQUENCE SIZE (1..MAX) OF GeneralNames OPTIONAL } 4.5.1 validationPolRef The validationPolRef item is defined in section 3.1.4.1. 4.5.2 validationPolValues If a client request the validation policy by values instead of by reference then the server uses the validationPolicyValues structure to communicate the policy values it used to validate the request. The validationPolValues syntax is: ValidationPolValues ::=SEQUENCE { validationAlg ValidationAlg, inhibitPolMap BOOLEAN, requireExplicitPol BOOLEAN, inhibitAnyPol BOOLEAN, isCA BOOLEAN, trustAnchors TrustAnchors, keyUsage [0] KeyUsage OPTIONAL, extendedKeyUsage [1] ExtKeyUsageSyntax OPTIONAL, validationPolicyAttr [2] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL } The optional keyUsage and ExtendedKeyUsage values are only necessary if there defined in the referenced policy or the client stated some requirements in the request. Each of these items is discussed in the following sections. Freeman, Housley, & Malpani [Page 39]
INTERNET DRAFT SCVP October 2004 4.5.2.1 validationAlg The validationAlg item is defined in section 3.1.5.2. 4.5.2.2 inhibitPolMap The inhibitPolMap item is defined in section 3.1.5.4. 4.5.2.3 requireExplicitPol The requireExplicitPol item is defined in section 3.1.5.5. 4.5.2.4 inhibitAnyPol The inhibitAnyPol item is defined in section 3.1.5.6. 4.5.2.5 isCA The isCA item is defined in section 3.1.5.7. 4.5.2.6 trustAnchors The trustAnchors item is defined in section 3.1.5.8. 4.5.2.7 keyUsage The optional keyUsage item is defined in [PKIX-1]. 4.5.2.8 extendedKeyUsage The optional extendedKeyUsage item is defined in [PKIX-1].]3.1.5.4 4.5.2.9 validationPolicyAttr The validationPolicyAtt item MAY contain Attributes. If present, each attribute in the sequence extends the policy values for the validation policy. This specification does not define any attributes. The facility is provided to allow future specifications to extend the SCVP. The syntax for Attribute is imported from [CMS]. 4.5.3 userFinalPolicySet The userFinalPolicySet contains the set of valid policy OIDs from the valid-policy-tree as defined in [PKIX-1] section 6. The userFinalPolicySet MUST be populated if the valid-policy-tree from the validation is not NULL. userFinalPolicySet MUST be absent if the valid-policy-tree from the validation is NULL. 4.5.4 permittedSubtrees Freeman, Housley, & Malpani [Page 40]
INTERNET DRAFT SCVP October 2004 permittedSubtrees is defined in [PKIX-1] section 6.1.2, This field MUST be populated when isCA is TRUE in the request and the validated path contains a non empty permitted-subtrees value. This field MAY be populated for other requests when the validated path contains a non empty permitted-subtrees value. 4.5.5 excludedSubtrees excludedSubtrees is defined in [PKIX-1] section 6.1.2, This field MUST be populated when isCA is TRUE in the request and the validated path contains a non empty excluded-subtrees value. This field MAY be populated for other requests when the validated path contains a non empty excluded-subtrees value. 4.5.6 validationPolicyAtt The validationPolicyAtt item MAY contain Attributes. If present, each attribute in the sequence extends the policy values for the validation policy. This specification does not define any attributes. The facility is provided to allow future specifications to extend the SCVP. The syntax for Attributes is imported from [CMS]. 4.6 requestRef The requestRef allows the SCVP client to identify the request that corresponds to this response from the server. It associates the response to a particular request using either a hash of the request or a copy of CVRequest from the request. The hash is calculated as described in [CMS] for SignedData and AuthenticatedData. That is, it covers the encapsulated content and authenticated attributes but not the unauthenticated attributes. The requestRef item does not provide authentication, but the requestRef does allow the client to determine that the request was not maliciously modified. The requestRef item allows the client to associate a response with a request. The requestNonce provides an alternative mechanism for matching requests and responses if the client has selected to include a full response. When the fullRequest alternative is used, the response provides a single data structure that is suitable for archive of the transaction. The requestRef item uses the RequestReference type, which has the following syntax: RequestReference ::= CHOICE { requestHash [0] HashValue, -- hash of CVRequest fullRequest [1] CVRequest } Freeman, Housley, & Malpani [Page 41]
INTERNET DRAFT SCVP October 2004 SCVP clients MUST support requestHash, and they MAY support fullRequest. SCVP servers MUST support using requestHash, and they SHOULD support using fullRequest. 4.6.1 requestHash The requestHash item is the hash of the CVRequest. By default, SHA-1 is used as the one-way hash function, but others can be used. The requestHash item serves two purposes. First, it allows a client to determine that the request was not maliciously modified. Second, it allows the client to associate a response with a request when using connectionless protocols. The requestNonce provides an alternative mechanism for matching requests and responses. The requestHash item uses the HashValue type, which has the following syntax: HashValue ::= SEQUENCE { algorithm AlgorithmIdentifier DEFAULT { sha-1 }, value OCTET STRING } sha-1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } The algorithm identifier for SHA-1 is imported from [PKIX-ALG]. It is repeated here for convenience. 4.6.2 fullRequest Like requestHash, the fullRequest alternative allows a client to determine that the request was not maliciously modified. It also provides a single data structure that is suitable for archive of the transaction. The fullRequest item uses the CVRequest type. The syntax and semantics of the CVRequest type are described in section 3. 4.7 requestorRef The optional requestorRef item is used by the client to identify the original requestor in cases where SCVP relay is used. The value is only of local significance to the client. If the SCVP client includes a requestorRef value in the request, then the SCVP server MUST return the same value if the server is generating a, non-cached response. 4.8 requestorName The optional requestorName item is used by the server with signed requests to return the identity of the client in the response. Freeman, Housley, & Malpani [Page 42]
INTERNET DRAFT SCVP October 2004 Mechanisms for matching this identifier with the authenticated identity are a matter of local server policy. In the case of non-cached responses to signed requests, the SCVP server MUST return a requestor name. A server SHOULD copy the selected identifier from a certificate or other credential used to authenticate the request. A SCVP server MAY use a client identifier from an out-of-band mechanism or omit the identifier from the response. In the case of cached responses to signed requests, the RequestorName MAY be present in the response. SCVP server that supports signed requests MUST support this item. 4.9 responder The optional responder item is used to identify the server. The value chosen is only of local significance to the SCVP server. The responder item MUST be included if the request included a requestorRef item. The responder item MUST be an octet string. No provisions are made to ensure uniqueness of the requestor octet string; however, all of the octets MUST have values other than zero. 4.10 replyObjects The replyObjects item returns requested objects to the SCVP client, each of which tells the client about a single certificate from the request. The replyObjects item MUST be present in the response, unless the response is reporting an error. The CertReply item MUST contain cert, replyStatus, replyValTime, replyChecks, replyWantBacks, and valdationPolicy items; and the CertReply item MAY contain the nextUpdate and certReplyExtensions items. A success response MUST contain one CertReply for each Query item in the request. The order is important. The first CertReply in the sequence MUST correspond to the first Query item in the request; the second CertReply in the sequence MUST correspond to the second Query item in the request; and so on. The checks item in the request determines the content of the replyChecks item in the response. The wantBack item in the request determines the content of the replyWantBacks item in the response. The queryExtensions items in the request controls the absence or the presence and content of the certReplyExtensions item in the response. The replyObjects item uses the ReplyObjects type, which has the following syntax: Freeman, Housley, & Malpani [Page 43]
INTERNET DRAFT SCVP October 2004 ReplyObjects ::= SEQUENCE SIZE (1..MAX) OF CertReply CertReply ::= SEQUENCE { cert CertReference, replyStatus ReplyStatus, replyValTime GeneralizedTime, replyChecks ReplyChecks, replyWantBacks ReplyWantBacks, validationErrors [0] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL, nextUpdate [1] GeneralizedTime OPTIONAL, certReplyExtensions [2] Extensions OPTIONAL } 4.10.1 cert The cert item contains either the public key certificate or the attribute certificate or a reference to the certificate about which the client is requesting information. The ASN.1 definition of Certificate is imported from [PKIX-1]; and the definition of AttributeCertificate is imported from [PKIX-AC]. 4.10.2 replyStatus The replyStatus item gives status information to the client about the request for the specific certificate. Note that the respStatus item is different than the replyStatus item. The respStatus item is the status of the whole request, while the replyStatus item is the status for the individual query item. The replyStatus item uses the ReplyStatus type, which has the following syntax: ReplyStatus ::= ENUMERATED { success (0), malformedPKC (1), malformedAC (2), unavailableValidityTime (3), referenceCertHashFail (4), certPathConstructFail (5), certPathNotValid (6), certPathNotValidNow (7) } The meaning of the various ReplyStatus values are: 0 Success: a definitive answer follows. 1 Failure: the public key certificate was malformed. 2 Failure: the attribute certificate was malformed. 3 Failure: historical data for the requested validity time is not available. Freeman, Housley, & Malpani [Page 44]
INTERNET DRAFT SCVP October 2004 4 Failure: the referenced certificate policy OID is not recognized. 5 Failure: no certification path could be constructed. 6 Failure: the constructed certification path is invalid. 7 Failure: the constructed certification path is invalid, but a query at a later time may be successful. Codes 1 and 2 are used to tell the client that the request was properly formed, but the certificate in question was not. This is especially useful to clients that do not parse certificates. 4.10.3 replyValTime The replyValTime item tells the time at which the information in the CertReply was correct. The replyValTime item represents the date and time in UTC, using GeneralizedTime type. The encoding rules for GeneralizedTime in section 3.1.8 MUST be used. Within the request, the optional validityTime item tells the date and time relative to which the SCVP client wants the server to perform the checks. If the validityTime is not present, the server MUST respond as if the client provided the date and time at which the server processes the request. The information in the CertReply item MUST be formatted as if the server created this portion of the response at the time indicated in the validityTime item of the query. However, if the server does not have appropriate historical information, the server MAY either return an error or return information for a later time. 4.10.4 replyChecks The replyChecks contains the responses to the checks item in the query. The replyChecks item repeats the object identifier (OID) from the query and an integer. The value of the integer indicates whether the requested check was successful. The OIDs in the checks item of the query are used to identify the corresponding replyChecks values. The OIDs in the replyChecks item MUST match the OIDs in the checks item in the request. The replyChecks item uses the ReplyChecks type, which has the following syntax: ReplyChecks ::= SEQUENCE OF ReplyCheck ReplyCheck ::= SEQUENCE { check OBJECT IDENTIFIER, status INTEGER } The status value for public key certification path building to a trusted root, { id-stc 1 }, can be one of the following: Freeman, Housley, & Malpani [Page 45]
INTERNET DRAFT SCVP October 2004 0: Built a path 1: Could not build a path The status value for public key certification path building to a trusted root along with simple validation processing, { id-stc 2 }, can be one of the following: 0: Valid 1: Not valid The status value for public key certification path building to a trusted root along with complete status checking, { id-stc 3 }, can be one of the following: 0: Good 1: Revoked 2: Revocation Offline 3: Revocation Unavailable Revocation offline means that the server or distribution point for the revocation information was connected to successfully without a network error but either no data returned or if data was returned it was stale. Revocation unavailable means that a network error was returned when an attempt was made to reach the server or distribution point. The status value for AC issuer certification path building to a trusted root, { id-stc 4 }, can be one of the following: 0: Built a path 1: Could not build a path The status value for AC issuer certification path building to a trusted root along with simple validation processing, { id-stc 5 }, can be one of the following: 0: Valid 1: Not valid The status value for AC issuer certification path building to a trusted root along with complete status checking, { id-stc 6 }, can be one of the following: 0: Good 1: Revoked 2: Revocation Offline 3: Revocation Unavailable The status value for revocation status checking of an AC as well as AC issuer certification path building to a trusted root along with Freeman, Housley, & Malpani [Page 46]
INTERNET DRAFT SCVP October 2004 complete status checking, { id-stc 7 }, can be one of the following: 0: Good 1: Revoked 2: Offline 3: Unavailable 4.10.5 replyWantBack The replyWantBack contains the responses to the wantBack item in the request. The replyWantBack item includes the object identifier (OID) from the wantBack item in the request and an octet string. Within the octet string is the requested value. The OIDs in the wantBack item in the request are used to identify the corresponding reply value. The OIDs in the replyWantBack item MUST match the OIDs in the wantBack item in the request. The replyWantBack item uses the ReplyWantBack type, which has the following syntax: ReplyWantBacks ::= SEQUENCE OF ReplyWantBack ReplyWantBack::= SEQUENCE { wb OBJECT IDENTIFIER, value OCTET STRING } The octet string value for the certification path used to verify the certificate in the request, { id-swb 1 }, contains the CertBundle type. The syntax and semantics of the CertBundle type are described in section3.1.9. The octet string value for the proof of revocation status, { id-swb 2 }, contains the RevocationInfos type. The syntax and semantics of the RevocationInfo type are described in section 3.1.10. The octet string value for the public key certificate status, { id- swb 3 }, contains an ASN.1 BOOLEAN type. The value will be TRUE if the certificate is valid, and the value will be FALSE if the certificate is not valid. The octet string value for the public key information, { id-swb 4 }, contains the SubjectPublicKeyInfo type. The syntax and semantics of the SubjectPublicKeyInfo type are described in [PKIX-1]. The octet string value for the AC issuer certification path used to verify the certificate in the request, { id-swb 5 }, contains the CertBundle type. The syntax and semantics of the CertBundle type are described in section 3.1.9. Freeman, Housley, & Malpani [Page 47]
INTERNET DRAFT SCVP October 2004 The octet string value for the proof of revocation status of the AC issuer certification path, { id-swb 6 }, contains the RevocationInfo type. The syntax and semantics of the RevocationInfo type are described in section 3.1.10. The octet string value for the proof of revocation status of the attribute certificate, { id-swb 7 }, contains the RevocationInfo type. The syntax and semantics of the RevocationInfo type are described in section 3.1.10. The octet string value for the attribute certificate status, { id- swb 8 }, contains an ASN.1 BOOLEAN type. The value will be TRUE if the certificate is valid, and the value will be FALSE if the certificate is not valid. 4.10.6 validationAlg The validationAlg item indicates the validation algorithm used by the SCVP server. The server MUST include the validation algorithm that was used. The syntax and semantics of the validationAlg item are descried in section 3.1.5.2 4.10.7 validationErrors The validationErrors item MUST only be present in failure responses. It MUST contains one or more OID representing the why the validation failed. 4.10.8 nextUpdate The nextUpdate item tells the time at which the server expects a refresh of information regarding the validity of the certificate to become available. The nextUpdate is especially interesting if the certificate revocation status information is not available or the certificate is suspended. The nextUpdate item represents the date and time in UTC, using the GeneralizedTime type. The encoding rules for GeneralizedTime in section 3.1.8 MUST be used. 4.10.9 certReplyExtensions The certReplyExtensions contains the responses to the queryExtension item in the request. The certReplyExtensions item uses the Extensions type defined in [PKIX-1]. The object identifiers (OIDs) in the queryExtension item in the request are used to identify the corresponding reply value. The certReplyExtensions item, when present, contains a sequence of Extension items, each of which contains an extnID item, a critical item, and an extnValue item. Freeman, Housley, & Malpani [Page 48]
INTERNET DRAFT SCVP October 2004 The extnID item is an identifier for the extension. It contains the OID that names the extension, and it MUST match one of the OIDs in the queryExtension item in the request. The critical item is a BOOLEAN, and it MUST be set to FALSE. The extnValue item contains an OCTET STRING. Within the OCTET STRING is the extension value. An ASN.1 type is specified for each extension, and identified by extnID. 4.11 responseNonce The responseNonce item contains an identifier to binds the request to the response. If the client includes a requestNonce value in the request and the server is generating a specific non-cached response to the request then the server MUST return the same value in the response. If the server is using a cached response to the request then it MUST omit the responseNonce field. If the server is returning a specific non-cached response to a request without a once, then the server MUST use value of the message-digest attribute in the signedAttrs within SignerInfo of the request as the value in the responseNonce field. The requestNonce item uses the octet string type. Client SHOULD support and servers MUST support responseNonce. 4.12 serverContextInfo The serverContextInfo item in a response is a mechanism for the server to pass some opaque context information to the client. If the client does not like the certification path retuned, it can make a new query and pass along this context information. Section 3.1.6 contains information about the client usage of this item. The context information is opaque to the client, but it provides information to the server that ensures that a different certification path will be returned (if another one can be found). The context information could indicate state on the server or it could contain a sequence of hashes of certification paths that have already been returned to the client. The protocol does not dictate any structure or requirements for this item. However, implementers should review the Security Considerations section of this document before selecting a structure. Freeman, Housley, & Malpani [Page 49]
INTERNET DRAFT SCVP October 2004 Servers that are incapable of returning additional paths MUST NOT include the serverContextInfo item in the response. 4.13 respExtensions The respExtensions item MAY contain Extensions. If present, each Extension in the sequence extends the response. This specification does not define any extensions. The facility is provided to allow future specifications to extend the SCVP. The syntax for Extensions is imported from [PKIX-1]. The respExtensions item, when present, contains a sequence of Extension items, each of which contains an extnID item, a critical item, and an extnValue item. The extnID item is an identifier for the extension. It contains the object identifier (OID) that names the extension. The critical item is a BOOLEAN. Each extension is designated as either critical (with a value of TRUE) or non-critical (with a value of FALSE). An SCVP client MUST reject the response if it encounters a critical extension it does not recognize; however, a non-critical extension MAY be ignored if it is not recognized. The extnValue item contains an OCTET STRING. Within the OCTET STRING is the extension value. An ASN.1 type is specified for each extension, and identified by extnID. 4.14 SCVP Response Validation There are two mechanisms for validation of SCVP responses, one based on the clients knowledge of a specific SCVP server key and the other based on validation of the certificate which signed the SCVP response 4.14.1 Simple Key Validation Simple key validation method is where the SCVP client has a local policy of one or more SCVP server keys which directly identify the set of valid SCVP servers. Mechanisms for storage of server keys or identifiers is a local matter. For example, a client could store cryptographic hashes of public keys used to verify signedData responses. Alternatively, a client could store shared symmetric keys used to HMAC authenticatedData responses. Simple key validation MUST be used by SCVP clients that cannot validate PKIX-1 certificates and are therefore making delegated path validation requests to the SCVP server[RQTMS]. It is a matter of local policy with these clients whether to use signedData or authenticatedData. Simple key validation MAY be used by other SCVP clients for other reasons. Freeman, Housley, & Malpani [Page 50]
INTERNET DRAFT SCVP October 2004 4.14.2 SCVP Server Certificate Validation It is a matter of local policy what validation policy is used by the client when validating responses. When validating signed SCVP responses, SCVP clients SHOULD use the validation algorithm defined in section 6 of PKIX-1. If the certificate used to sign the validation policy responses and signedData validation responses contains the key usage extension [PKIX-1 section 4.2.1.3] it MUST have either the digital signature or the non-repudiation bits set or both. If the certificate for authenticatedData validation responses contains the key usage extension it MUST have the key agreement bit set. If the certificates used on a validation policy response or a validation response contains the extended Key Usage extension [PKIX-1 section 4.2.1.13] it MUST contain the following OID id-kp-scvpServer OBJECT IDENTIFIER ::= { id-kp 15 } 5 Server Policy Request A SCVP client uses the valPolRequest item to request the list of validation policies supported by the SCVP server. When a valPolRequest is encapsulated in a MIME body part, it MUST be carried in an application/vp-request MIME body part. The request consists of a valPolRequest encapsulated in a ContentInfo. The request is not signed by the client. ContentInfo { contentType id-ct-scvp-valPolRequest, -- (1.2.840.113549.1.9.16.1.12) content valPolRequest } The valPolRequest type has the following syntax: VPRequest ::= SEQUENCE { vpRequestVersion INTEGER, requestNonce OCTET STRING} 5.1 vpRequestVersion The vpRequestVersion item is described in section 3.1.requestNonce 5.2 requestNonce The requestNonce item contains a request identifier generated by the SCVP client. If the server returns a specific response it MUST Freeman, Housley, & Malpani [Page 51]
INTERNET DRAFT SCVP October 2004 include the requestNonce from the request in the response, but MAY return a cached response which MUST NOT include a requestNonce. 6 Validation Policy Response In response to a valPolRequest, the SCVP server provides a valPolResponse. The valPolResponse MAY not unique to any valPolRequest, so may be reused by the server in response to multiple vbalPolRequests. The valPolResponse also has an indication of how frequently the valPolResponse may be reissued. When a PolResponse is encapsulated in a MIME body part, it MUST be carried in an application/vp-response MIME body part. The response consists of a valPolResponse encapsulated in a ContentInfo. The response MUST be signed by the server using its digital signature certificate. ContentInfo { contentType id-ct-scvp-valPolResponse, -- (1.2.840.113549.1.9.16.1.13) content valPolResponse } The valPolResponse type has the following syntax: VPResponse ::= SEQUENCE { vpResponseVersion INTEGER, maxCVResponseVersion INTEGER, maxVPResponseVersion INTEGER, defaultPolicyID INTEGER, thisUpdate GeneralizedTime, nextUpdate GeneralizedTime OPTIONAL, validationPolices SEQUENCE OF ValidationPolRef, validationAlgs SEQUENCE OF OBJECT IDENTIFIER, authPolicies SEQUENCE OF AuthPolicy, responseTypes ResponseTypes, defaultPolicyValues ValidationPolValues, dhPublicKeyInfo SEQUENCE OF DHPublicKeyInfo, clockSkew [0] INTEGER OPTIONAL, requestNonce [1] OCTET STRING OPTIONAL } ResponseTypes ::= ENUMERATED { cached-only (0), specific-signed-only (1), cached-and-specific-signed (2)} SCVP clients that support validation policy requests MUST support SCVP responses. SCVP servers MUST support validation policy responses. Freeman, Housley, & Malpani [Page 52]
INTERNET DRAFT SCVP October 2004 SCVP servers MUST support cached policy responses and MAY support specific responses to policy request. 6.1 vpResponseVersion The syntax and semantics of the vpResponseVersion item is described in section 3.1. The vpResponseVersion used MUST be the same as the vpRequestVersion unless the client has used a value grater than the values the server supports. If the client submits a vpRequestVersion grater then the version supported by the server, it MUST return an a vpResponseVersion using the highest version number the server supports as the version number. 6.2 maxCVRequestVersion The maxCVRequestVersion defines the maximum version number for CV requests that the server supports 6.3 maxVPRequestVersion The maxVPRequestVersion defines the maximum version number for VP requests that the server supports 6.4 defaultPolicyID An integer that uniquely represents the version of the default validation policy as represented by the trustAnchors, validationPolicy, validationAlg, authPolicies, clockSkew and authDataCerts. If any of these values change, the server MUST create a new PolResponse with a new defaultPolicyID. If the policy and therefore the defaultPolicyID has not changed, then the server may reused defaultPolicyID across multiple PolResponse messages. However if the server having changed the policy, then reverts to an earlier policy, the server MUST NOT revert the policy ID as well, but MUST select another unique value. 6.5 thisUpdate This field indicates the signing date & time of this policy response. GeneralizedTime values MUST be expressed Greenwich Mean Time (Zulu) and interpreted as defined in section 3.1.8. 6.6 nextUpdate This optional field indicates the expected publication date & time of the next policy response. Freeman, Housley, & Malpani [Page 53]
INTERNET DRAFT SCVP October 2004 If this field is omitted it indicates a non-cached response generated in response to a specific request, then the polResponse is bound to a specific request. If this filed is omitted the requestNonce files MUST be present and the value copied from the request. If this field is preset it indicates a non-cached response, then the polResponse is not bound to a specific request. A SCVP server MUST periodically generate the new response as defined by the next update time and use the same polResponse used for multiple requests. It is a matter of local server policy to return a cached or non- cached specific response. GeneralizedTime values MUST be expressed Greenwich Mean Time (Zulu) as specified in section 3.1.8. 6.7 trustAnchors The trustAnchors item specifies the default trust anchors that the SCVP server will use if the request references a validation policy which does not define any trust anchors and no trust anchors are present in the request. 6.8 validationPolicies The validationPolicies item contains a sequence of ValidationPolRef representing the validation policies supported by the server. It is a matter of local policy if the server whishes to processes requests using the default validation policy, and if it does not, then it MUST NOT include the id-svp-defaultValPolicy in this list. 6.9 validationAlgs The validationAlgs item contains a sequence of OIDs. Each OID identifies a validation algorithm supported by the server. 6.10 authPolicies The authPolicies item contains a sequence of policy references for authenticating to the SCVP server. The reference to the authentication policy can be either an OID where the client and server have agreed the OID to represent a authentication policy or a URI where the URI points to a human readable definition of the policy. The list of policies is intended to document to the client if authentication is required for some requests and if so how. AuthPolicy ::= CHOICE { authPolRefByOID [0] OBJECT IDENTIFIER, Freeman, Housley, & Malpani [Page 54]
INTERNET DRAFT SCVP October 2004 authPolRefByURI [1] IA5String} 6.11 responseTypes Response types allows the server to publish the range of response types it supports. Cache only means the server will only return cached responses to requests. Unique signed responses means the server will return a specific response to the request i.e. containing the requestors nonce. Both means the server will return either depending on the request. 6.12 dhPublicKeyInfo The dhPublicKeyInfo is a sequence of one or more Diffie-Hellman public keys and associated parameters. It is used by clients making authenticatedData requests to the server. dhPublicKeyInfo has the following structure: DHPublicKeyInfo ::= SEQUENCE { dhPublicKey DHPublicKey, domainParameters DomainParameters} DHPublicKeyInformation MUST be supported by a SCVP server. SCVP serverS MUST support a 1536-bit MODP group key (group 5) as defined in [IKE-GROUPS]. SCVP servers MAY support other group keys as defined in [IKE] or [IKE-GROUPS]. 6.13 clockSkew The clockSkew item is the number of minutes the server will allow for clock skew. If absent the server MUST use the default value of 10 minutes. 6.14 defaultValPolicy This is the default validation policy used by the server. It contains a VaidationPolValues which is defined in section 4.5 A server will use these default values when The request references the default validation policy and the client does not override the defaults vaues by supplying other values in the request The request references a non-default validation policy, which does not define every parameter necessary as defined by the validation algorithm and the client further omits these missing values from request. The server MUST use its default value for any parameter not defined by the referenced non-default policy, and not specified in the request. Freeman, Housley, & Malpani [Page 55]
INTERNET DRAFT SCVP October 2004 This allows the client to optimize the request by omitting parameters which match the server default values. 7 SCVP Server Relay In some network environments, especially ones that include firewalls, an SCVP server might not be able to obtain all of the information that it needs to process a request. However, the server might be configured to use the services of one or more other SCVP servers to fulfill all requests. In such cases, the SCVP client is unaware that the initial SCVP server is using the services of other SCVP servers. The initial SCVP server acts as a client to another SCVP server. Unlike the original client, the SCVP server is expected to have moderate computing and memory resources. This section describes SCVP server-to-SCVP server exchanges. This section does not impose any requirements on SCVP clients that are not also SCVP servers. Further, this section does not impose any requirements on SCVP servers that do not relay requests to other SCVP servers. When one SCVP server relays a request to another server, in an incorrectly configured system of servers, it is possible that the same request will be relayed back again. Any SCVP server that relays requests MUST implement the conventions described in this section to detect and break loops. When an SCVP server relays a request, the request MUST include the requestor item. If the request to be relayed already contains a requestor item, then server-generated request MUST contain a requestor item constructed from this value followed by a zero octet followed by the identifier of the SCVP server. If the request to be relayed does not contain a requestor item, then server-generated request MUST contain only the identifier of the SCVP server. When an SVCP server receives a request that contains a requestor item, the server MUST check for its own identifier. The identifier could be located at the beginning of the octet string followed by a zero octet, or it could be located between two zero octets. If the server discovers its own identifier in the requestor item, it MUST respond with an error, setting the cvResponseStatus to 40. 8 SCVP ASN.1 Module This section defines the syntax for SCVP request-response pairs. The semantics for the messages are defined in sections 3, 4, 5, and 6. The SCVP ASN.1 module follows. SCVP { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) 21 } Freeman, Housley, & Malpani [Page 56]
INTERNET DRAFT SCVP October 2004 DEFINITIONS IMPLICIT TAGS ::= BEGIN IMPORTS DHPublicKey, DomainParameters FROM PKIX1Algorithms88 RFC 3279 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-algorithms(17) AlgorithmIdentifier, Certificate, Extensions, GeneralNames, UTF8String, CertificateList, keyPurposeId FROM PKIX1Explicit88 -- RFC 3280 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) 18 } AttributeCertificate FROM PKIXAttributeCertificate -- RFC 3281 { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) 12 } ESSCertID FROM ExtendedSecurityServices -- RFC 2634 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) 2 } ; -- SCVP Certificate Validation Request id-ct OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) id-smime(16) 1 } id-ct-scvp-certValRequest OBJECT IDENTIFIER ::= { id-ct 10 } CVRequest ::= SEQUENCE { cvRequestVersion INTEGER, query Query, requestorRef [0] SEQUENCE SIZE (1..MAX) OF OCTET STRING OPTIONAL, requestNonce [1] OCTET STRING OPTIONAL, reqestExtensions [2] Extensions OPTIONAL, dhPublicKey [3] DHPublicKey OPTIONAL} Query ::= SEQUENCE { queriedCerts SEQUENCE SIZE (1..MAX) OF CertReference, checks CertChecks, wantBack WantBack, validationPolicy ValidationPolicy, responseFlags ResponseFlags OPTIONAL, Freeman, Housley, & Malpani [Page 57]
INTERNET DRAFT SCVP October 2004 serverContextInfo [0] OCTET STRING OPTIONAL, validationTime [1] GeneralizedTime OPTIONAL, intermediateCerts [2] CertBundle OPTIONAL, revInfos [3] RevocationInfos OPTIONAL, producedAt [4] GeneralizedTime OPTIONAL, queryExtensions [5] Extensions OPTIONAL } CertReference::= CHOICE { pkc PKCReference, ac ACReference } PKCReference ::= CHOICE { cert [0] Certificate, pkcRef [1] ESSCertID } ACReference ::= CHOICE { attrCert [2] AttributeCertificate, acRef [3] ESSCertID } ValidationPolicy ::= SEQUENCE { validationPolRef ValidationPolRef, validationAlg [0] ValidationAlg OPTIONAL, userPolicySet [1] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL, inhibitPolicyMapping [2] BOOLEAN OPTIONAL, requireExplicitPolicy [3] BOOLEAN OPTIONAL, inhibitAnyPolicy [4] BOOLEAN OPTIONAL, isCA [5] BOOLEAN OPTIONAL, trustAnchors [6] TrustAnchors OPTIONAL, keyUsages [7] SEQUENCE SIZE (1..MAX) OF KeyUsage OPTIONAL, extendedKeyUsages [8] ExtKeyUsageSyntax OPTIONAL} CertChecks ::= SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER WantBack ::= SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER ValidationPolRef ::= CHOICE { valPolRefByOID [0] OBJECT IDENTIFIER, valPolRefByURI [1] IA5String} ValidationAlg ::= SEQUENCE { valAlgId OBJECT IDENTIFIER, parameters ANY DEFINED BY valAlgId OPTIONAL } nameValidationAlg ::= SEQUENCE { keyPurposeId OBJECT IDENTIFIER, validationName GeneralNames } TrustAnchors ::= SEQUENCE SIZE (1..MAX) OF PKCReference Freeman, Housley, & Malpani [Page 58]
INTERNET DRAFT SCVP October 2004 ResponseFlags ::= SEQUENCE { responseRefHash BOOLEAN DEFAULT TRUE, responseValidationPolByRef BOOLEAN DEFAULT TRUE, signResponse BOOLEAN DEFAULT TRUE } CertBundle ::= SEQUENCE SIZE (1..MAX) OF PKCReference RevocationInfos ::= SEQUENCE SIZE (1..MAX) OF RevocationInfo RevocationInfo ::= CHOICE { crl [0] CertificateList, delta-crl [1] CertificateList, ocsp [2] OCSPResponse, other [3] OtherRevInfo } OtherRevInfo ::= SEQUENCE { riType OBJECT IDENTIFIER, riValue ANY DEFINED BY riType } -- SCVP Certificate Validation Response id-ct-scvp-certValResponse OBJECT IDENTIFIER ::= { id-ct 11 } CVResponse ::= SEQUENCE { cvResponseVersion cvResponseVersion INTEGER, policyID INTEGER, producedAt GeneralizedTime, responseStatus ResponseStatus, respValidationPolicy [0] RespValPolicy OPTIONAL, requestRef [1] RequestReference OPTIONAL, requestorRef [2] OCTET STRING OPTIONAL, requestorName [3] GeneralNames OPTIONAL, responder [4] OCTET STRING OPTIONAL, replyObjects [5] ReplyObjects OPTIONAL, respNonce [6] OCTET STRING OPTIONAL, serverContextInfo [7] OCTET STRING OPTIONAL, cvResponseExtensions [8] Extensions OPTIONAL } responseStatus ::= SEQUENCE { statusCode CVStatusCode, errorMessage [0] UTF8String OPTIONAL } CVStatusCode ::= ENUMERATED { okay (0), skipUnrecognizedItems (1), tooBusy (10), invalidREquest (11), internalError (12), badStructure (20), Freeman, Housley, & Malpani [Page 59]
INTERNET DRAFT SCVP October 2004 unsupportedVersion (21), abortUnrecognizedItems (22), unrecognizedSigKey (23), badSignature (24), unableToDecode (25), notAuthorized (26), unsupportedChecks (27), unsupportedWantBacks (28), unsupportedSignature (29), invalidSignature (30), relayingLoop (40), unrecognizedValPol (50), unrecognizedValAlg (51), fullRequestRefUnsuported (52}, fullPolResponseUnsuported (53), inhibitPolMapUnsuported (54), requireExpPolUnsuported (55), ignoreAnyPolUnsuported (56), validityTimeUnsuported (57), unrecognizedUserPolOID (60), unrecognizedValPolOID (61), unrecognizedValAlgOID (62), unrecognizedCritQueryExt (63), unrecognizedCriticalExt (64)} RespValidationPolicy ::= SEQUENCE { validationPolRef ValidationPolRef, validationPolValues [0] ValidationPolValues OPTIONAL userFinalPolicySet [1] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL permittedSubtrees [2] SEQUENCE SIZE (1..MAX) OF GeneralNames OPTIONAL excludedSubtrees [3] SEQUENCE SIZE (1..MAX) OF GeneralNames OPTIONAL} ValidationPolValues ::=SEQUENCE { validationAlg ValidationAlg, inhibitPolMap BOOLEAN DEFAULT FALSE, requireExplicitPol BOOLEAN DEFAULT FALSE, inhibitAnyPol BOOLEAN DEFAULT FALSE, isCA BOOLEAN DEFAULT FALSE, trustAnchors TrustAnchors, keyUsage [0] KeyUsage OPTIONAL, extendedKeyUsage [1] ExtKeyUsageSyntax OPTIONAL, validationPolicyAtt [2] SEQUENCE SIZE (1..MAX) OF Attribute OPTIONAL } RequestReference ::= CHOICE { requestHash [0] HashValue, -- hash of CVRequest fullRequest [1] CVRequest } Freeman, Housley, & Malpani [Page 60]
INTERNET DRAFT SCVP October 2004 HashValue ::= SEQUENCE { algorithm AlgorithmIdentifier DEFAULT { sha-1 }, value OCTET STRING } sha-1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) oiw(14) secsig(3) algorithm(2) 26 } ReplyObjects ::= SEQUENCE SIZE (1..MAX) OF CertReply CertReply ::= SEQUENCE { cert CertReference, replyStatus ReplyStatus, replyValTime GeneralizedTime, replyChecks ReplyChecks, replyWantBacks ReplyWantBacks, validationErrors [0] SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER OPTIONAL, nextUpdate [1] GeneralizedTime OPTIONAL, certReplyExtensions [2] Extensions OPTIONAL } ReplyCertificate ::= CHOICE { pkc [1] Certificate, ac [2] AttributeCertificate } ReplyStatus ::= ENUMERATED { success (0), malformedPKC (1), malformedAC (2), unavailableValidityTime (3), referenceCertHashFail (4), certPathConstructFail (5), certPathNotValid (6), certPathNotValidNow (7)} ReplyChecks ::= SEQUENCE OF ReplyCheck ReplyCheck ::= SEQUENCE { check OBJECT IDENTIFIER, status INTEGER } ReplyWantBacks ::= SEQUENCE OF ReplyWantBack ReplyWantBack::= SEQUENCE { wb OBJECT IDENTIFIER, value OCTET STRING } -- SCVP Validation Policies Request id-ct-scvp-valPolRequest OBJECT IDENTIFIER ::= { id-ct 12 } Freeman, Housley, & Malpani [Page 61]
INTERNET DRAFT SCVP October 2004 VPRequest ::= SEQUENCE { scvpVersion INTEGER, requestNonce OCTET STRING} -- SCVP Validation Policies Response id-ct-scvp-valPolResponse OBJECT IDENTIFIER ::= { id-ct 13 } VPResponse ::= SEQUENCE { vpResponseVersion INTEGER, maxCVResponseVersion INTEGER, maxVPResponseVersion INTEGER, defaultPolicyID INTEGER, thisUpdate GeneralizedTime, nextUpdate GeneralizedTime OPTIONAL, validationPolices SEQUENCE OF ValidationPolRef, validationAlgs SEQUENCE OF OBJECT IDENTIFIER, authPolicies SEQUENCE OF AuthPolicy, responseTypes ResponseTypes, defaultValidationPolicy ValidationPolValues, dhPublicKeyInfo SEQUENCE OF DHPublicKeyInfo, clockSkew [0] INTEGER OPTIONAL, requestNonce [1] OCTET STRING OPTIONAL } ResponseTypes ::= ENUMERATED { cached-only (0), specific-signed only (1), cached-and-specific-signed (2)} DHPublicKeyInfo ::= SEQUENCE { dhPublicKey DHPublicKey, domainParameters DomainParameters} -- SCVP Check Identifiers id-stc OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 17 } id-stc-build-pkc-path OBJECT IDENTIFIER ::= { id-stc 1 } id-stc-build-valid-pkc-path OBJECT IDENTIFIER ::= { id-stc 2 } id-stc-build-status-checked-pkc-path OBJECT IDENTIFIER ::= { id-stc 3 } id-stc-build-aa-path OBJECT IDENTIFIER ::= { id-stc 4 } id-stc-build-valid-aa-path OBJECT IDENTIFIER ::= { id-stc 5 } -- SCVP WantBack Identifiers id-swb OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 18 } Freeman, Housley, & Malpani [Page 62]
INTERNET DRAFT SCVP October 2004 id-swb-pkc-best-cert-path OBJECT IDENTIFIER ::= { id-swb 1 } id-swb-pkc-revocation-info OBJECT IDENTIFIER ::= { id-swb 2 } id-swb-pkc-cert-status OBJECT IDENTIFIER ::= { id-swb 3 } id-swb-pkc-public-key-info OBJECT IDENTIFIER ::= { id-swb 4 } id-swb-aa-cert-path OBJECT IDENTIFIER ::= { id-swb 5 } id-swb-aa-revocation-info OBJECT IDENTIFIER ::= { id-swb 6 } id-swb-ac-revocation-info OBJECT IDENTIFIER ::= { id-swb 7 } id-swb-ac-cert-status OBJECT IDENTIFIER ::= { id-swb 8 } id-swb-non-cached-resp OBJECT IDENTIFIER ::= { id-swb 9 } id-swb-pkc-cert OBJECT IDENTIFIER ::= { id-swb 10} id-swb-ac-cert OBJECT IDENTIFIER ::= { id-swb 11} id-swb-pkc-all-valid-cert-paths OBJECT IDENTIFIER ::= { id-swb 13} -- SCVP Validation Algorithm Identifiers id-svp OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) 19 } id-svp-defaultValAlg OBJECT IDENTIFIER ::= { id-svp 1 } -- SCVP Basic Validation Algorithm Identifier id-svp-basicValAlg OBJECT IDENTIFIER ::= { id-svp 3 } -- SCVP Basic Validation Algorithm Errors id-bvae OBJECT IDENTIFIER ::= { id-svp-basicValAlg 1 } id-bvae-expired OBJECT IDENTIFIER ::= { id-bvae 1 } id-bvae-not-yet-valid OBJECT IDENTIFIER ::= { id-bvae 2 } id-bvae-wrong-anchor OBJECT IDENTIFIER ::= { id-bvae 3 } id-bvae-partial-chain OBJECT IDENTIFIER ::= { id-bvae 4 } id-bvae-invalid-key-usage OBJECT IDENTIFIER ::= { id-bvae 10 } id-bvae-invalid-Purpose OBJECT IDENTIFIER ::= { id-bvae 11 } id-bvae-invalid-policy OBJECT IDENTIFIER ::= { id-bvae 12 } id-bvae-invalid-name OBJECT IDENTIFIER ::= { id-bvae 13 } id-bvae-invalid-entity OBJECT IDENTIFIER ::= { id-bvae 14 } id-bvae-invalid-depth OBJECT IDENTIFIER ::= { id-bvae 15 } -- SCVP Name Validation Algorithm Identifier id-svp-NameValAlg OBJECT IDENTIFIER ::= { id-svp 2 } -- SCVP Name Validation Algorithm Errors id-nvae OBJECT IDENTIFIER ::= { id-svp-NameValPol 1 } id-nvae-name-mismatch OBJECT IDENTIFIER ::= { id-nvae 1 } id-nvae-no-name OBJECT IDENTIFIER ::= { id-nvae 2 } Freeman, Housley, & Malpani [Page 63]
INTERNET DRAFT SCVP October 2004 id-nvae-unknown-pupose OBJECT IDENTIFIER ::= { id-nvae 3 } id-nvae-bad-name OBJECT IDENTIFIER ::= { id-nvae 4 } id-nvae-bad-name-type OBJECT IDENTIFIER ::= { id-nvae 5 } id-nvae-mixed-names OBJECT IDENTIFIER ::= { id-nvae 6 } END 9 Security Considerations The following are in addition to the [CMS] security considerations A client that trusts a server's response for validation of a certificate inherently trusts that server as much as it would trust its own validation software. This means that if an attacker compromises a trusted SCVP server, the attacker can change the validation processing for every client that relies on that server. Thus, an SCVP server must be protected at least as well as the trust anchors that the SCVP server trusts. Clients MUST check the requestRef item in the response and ensure that it matches their original request. Requests contain a lot of information that affects the response and clients need to ensure that the server response corresponds to the expected request. When the SCVP response is used to determine the validity of a certificate, the client MUST validate the signature on the response to ensure that the expected SCVP server generated it. If the client does not check the signature on the response, a man-in-the- middle attack could fool the client into believing modified responses from the server, or responses to questions the client did not ask. If the client does not include a requestNonce item, or if the client does not check that the requestNonce in the response matches the value in the request, an attacker can replay previous responses from the SCVP server. If the server does not require some sort of authorization (such as signed requests), an attacker can get the server to respond to arbitrary requests. Such responses may give the attacker information about weaknesses in the server or about the timeliness of the server's checking. This information may be valuable for a future attack. If the server uses the serverContextInformation to indicate some server state associated with a requestor, implementers must take appropriate measures against denial of service attacks where an attacker sends in a lot of requests at one time to force the server to keep a lot of state information. Freeman, Housley, & Malpani [Page 64]
INTERNET DRAFT SCVP October 2004 SCVP does not include any confidentiality mechanisms. If confidentiality is needed, it can be achieved with a lower-layer security protocol. The only validation policy references which are truly persistent are OIDs. If the ownership of the policy could in any way be an issue, then OIDs should be the type reference of choice. However in many situations, even though URIs are technically non-persistent, the use of an URI is much more readily understood because of its widespread use elsewhere, and with many organizations they may be viewed as persistent for practical purposes. Therefore in these situations use of URI many be more attractive. Certificate validation is expensive and there are performance benefits in caching and reusing the result of a validation - - especially for high volume server processes. Caching end entity certificate would typically result in low hit rates against the cashe so is therefore inefficient. Caching CA certificates should yield much higher hit rates, but this needs to be done carefully because it could lead to the wrong result. One way this to achieve caching at the CA certificate level is to build a client which has enough of the chain validation logic to validate an end entity certificate to a CA certificate. The client can then use SCVP to validate the CA certificate, cache the result and locally validate end entity certificates against the cache of known good CA certificates. Attempting this kind of optimization with intermediate CA certificates could cause problems in some edge cases - - especially with chains involving self-issued certificates so caches should only be attempted with end entity issuing CA certificate. If an SCVP client is not operating on a network with good physical protection, it must ensure that there is integrity over the SCVP request\response pair and ensure that the response cannot be a replay of a cached response obtained by another client. It can do this by using a protected transport such as TLS. It can also do this by using the Diffie-hellman keys to sign the request. It can also use signing keys and request a fresh response from the server. 10 References Normative and informative references are provided. 10.1 Normative References [STDWORDS] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. http://www.ietf.org/rfc/rfc2119.txt Freeman, Housley, & Malpani [Page 65]
INTERNET DRAFT SCVP October 2004 [CMS] Housley, R., "Cryptographic Message Syntax", RFC 2630,June 1999. http://www.ietf.org/rfc/rfc2630.txt [OCSP] Myers, M., Ankney, R., Malpani, A., Galperin, S. and C. Adams, "X.509 Internet Public Key Infrastructure - Online Certificate Status Protocol - OCSP", RFC 2560, June 1999. http://www.ietf.org/rfc/rfc2560.txt [PKIX-1] Housley, R., Polk, T, Ford, W. and Solo, D., "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3280, April 2002. http://www.ietf.org/rfc/rfc3280.txt [PKIX-AC] Farrell, S., and R. Housley, "An Internet Attribute Certificate Profile for Authorization", RFC 3281, April 2002. http://www.ietf.org/rfc/rfc3281.txt [PKIX-ALG] Polk, W., Housley, R. and L. Bassham, "Algorithms and Identifiers for the Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 3279, April 2002. http://www.ietf.org/rfc/rfc3280.txt [SHA-1] National Institute of Standards and Technology, "Secure Hash Standard", NIST FIPS Pub 180-1, April 1995. [UTF8] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998. http://www.ietf.org/rfc/rfc2279.txt [ESS] Hoffman, P., "Enhanced Security Services for S/MIME", RFC 2634, June 1999. http://www.ietf.org/rfc/rfc2634.txt [HTTP-TLS] Rescorla, E., "HTTP Over TLS", RFC2818, May 2000. http://www.ietf.org/rfc/rfc2818.txt [SMIME-CERT] B. Ramsdell, Ed. Secure/Multipurpose Internet Mail Extensions (S/MIME) Version 3.1 Certificate Handling RFC3850, July 2004. http://www.ietf.org/rfc/rfc3850.txt [IKE] D. Harkins, D. Carrel. The Internet Key Exchange RFC2409, November 1998 http://www.ietf.org/rfc/rfc2409.txt Freeman, Housley, & Malpani [Page 66]
INTERNET DRAFT SCVP October 2004 [IKE-GROUPS] T. Kivinen, M. Kojo More Modular Exponential (MODP) Diffie-Hellman groups for Internet Key Exchange (IKE) RFC3526, May 2003 http://www.ietf.org/rfc/rfc3526.txt 10.2 Informative References [HTTP] Fielding, R., Gettys, J., Mogul, J., Frystyk, H. and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2068, January 1997. [RQMTS] Pinkas, D., and R. Housley, "Delegated Path Validation and Delegated Path Discovery Protocol Requirements", RFC 3379, September 2002. 11 Acknowledgments The lively debate in the PKIX Working Group has made a significant impact on this protocol. Special thanks to the following for their contributions to this standard and diligence in greatly improving this document. Denis Pinkas Phillip Hallam-Baker Mike Myers Frank Balluffi Ameya Talwalkar John Thielens Peter Sylvester Yuriy Dzambasow Sean P. Turner Wen-Cheng Wang Francis Dupont Dave Engberg Faisal Maqsood David A. Cooper Thanks also to the workgroup chairs Tim Polk and Steve Kent in their support and help. Appendix A -- MIME Registrations Four MIME type registrations are provided in this appendix. A.1 application/cv-request To: ietf-types@iana.org Subject: Registration of MIME media type application/cv-request MIME media type name: application Freeman, Housley, & Malpani [Page 67]
INTERNET DRAFT SCVP October 2004 MIME subtype name: cv-request Required parameters: format Optional parameters: None Encoding considerations: binary 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 Simple Certificate Validation Protocol (SCVP) Applications which use this media type: SCVP clients Additional information: Magic number(s): None File extension(s): .SCQ Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani <ambarish@malpani.biz> Intended usage: COMMON Author/Change controller: Ambarish Malpani <ambarish@malpani.biz> A.2 application/cv-response To: ietf-types@iana.org Subject: Registration of MIME media type application/cv-response MIME media type name: application MIME subtype name: cv-response Required parameters: format Optional parameters: None Encoding considerations: binary Security considerations: Unless reporting an error, the response is cryptographically signed Interoperability considerations: None Freeman, Housley, & Malpani [Page 68]
INTERNET DRAFT SCVP October 2004 Published specification: IETF PKIX Working Group Draft on Simple Certificate Validation Protocol (SCVP) Applications which use this media type: SCVP servers Additional information: Magic number(s): None File extension(s): .SCS Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani <ambarish@malpani.biz> Intended usage: COMMON Author/Change controller: Ambarish Malpani <ambarish@malpani.biz> A.3 application/vp-request To: ietf-types@iana.org Subject: Registration of MIME media type application/vp-request MIME media type name: application MIME subtype name: vp-request Required parameters: format Optional parameters: None Encoding considerations: binary Security considerations: Carries a request for information. Interoperability considerations: None Published specification: IETF PKIX Working Group Draft on Simple Certificate Validation Protocol (SCVP) Applications which use this media type: SCVP clients Additional information: Magic number(s): None File extension(s): .SPQ Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani <ambarish@malpani.biz> Freeman, Housley, & Malpani [Page 69]
INTERNET DRAFT SCVP October 2004 Intended usage: COMMON Author/Change controller: Ambarish Malpani <ambarish@malpani.biz> A.4 application/vp-response To: ietf-types@iana.org Subject: Registration of MIME media type application/vp-response MIME media type name: application MIME subtype name: vp-response Required parameters: format Optional parameters: None Encoding considerations: Binary Security considerations: None Interoperability considerations: None Published specification: IETF PKIX Working Group Draft on Simple Certificate Validation Protocol (SCVP) Applications which use this media type: SCVP servers Additional information: Magic number(s): None File extension(s): .SPP Macintosh File Type Code(s): none Person & email address to contact for further information: Ambarish Malpani <ambarish@malpani.biz> Intended usage: COMMON Author/Change controller: Ambarish Malpani <ambarish@malpani.biz> Appendix B -- SCVP over HTTP This appendix describes the formatting conventions for the SCVP request and response when carried by HTTP. B.1 SCVP Request HTTP based SCVP requests can use the POST method to submit their requests. Where privacy is a requirement, SCVP transactions Freeman, Housley, & Malpani [Page 70]
INTERNET DRAFT SCVP October 2004 exchanged using HTTP MAY be protected using either TLS/SSL or some other lower layer protocol. An SCVP request using the POST method is constructed as follows: The Content-Type header MUST have the value "application/cv- request". The Content-Length header MUST be present and have the exact length of the request. The body of the message is the binary value of the DER encoding of the VPRequest. Other HTTP headers MAY be present and MAY be ignored if not understood by the requestor. Sample Content-Type headers are: Content-Type: application/cv-policy-request B.2 SCVP Response An HTTP-based SCVP response is composed of the appropriate HTTP headers, followed by the binary value of the DER encoding of the CVResponse. The Content-Type header MUST have the value "application/cv- response". The Content-Length header MUST be present and specify the length of the response. Other HTTP headers MAY be present and MAY be ignored if not understood by the requestor. B.3 SCVP Policy Request HTTP based SCVP policy requests can use the POST method to submit their requests. Where privacy is a requirement, SCVP transactions exchanged using HTTP MAY be protected using either TLS/SSL or some other lower layer protocol. An SCVP request using the POST method is constructed as follows: The Content-Type header MUST have the value "application/vp- request". The Content-Length header MUST be present and have the exact length of the request. The body of the message is the binary value of the DER encoding of the VPRequest. Other HTTP headers MAY be present and MAY be ignored if not understood by the requestor. Freeman, Housley, & Malpani [Page 71]
INTERNET DRAFT SCVP October 2004 Sample Content-Type headers are: Content-Type: application/vp-request B.4 SCVP Policy Response An HTTP-based SCVP policy response is composed of the appropriate HTTP headers, followed by the binary value of the DER encoding of the VPResponse. The Content-Type header MUST have the value "application/vp- response". The Content-Length header MUST be present and specify the length of the response. Other HTTP headers MAY be present and MAY be ignored if not understood by the requestor. Appendix C -- Author Contact Information Trevor Freeman Microsoft Corporation, One Microsoft way. Redmond, WA 98052 USA. trevorf@microsoft.com Russell Housley Vigil Security, LLC 918 Spring Knoll Drive Herndon, VA 20170 USA housley@Vigilsec.com Ambarish Malpani Malpani Consulting Services ambarish@malpani.biz Freeman, Housley, & Malpani [Page 72]
INTERNET DRAFT SCVP October 2004 Full Copyright Statement "Copyright (C) The Internet Society (2004). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights." "This document and the information contained herein are provided on An "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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." 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. In addition, the ASN.1 modules presented may be used in whole or in part without inclusion of the copyright notice. 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 shall be followed, or as required to translate it into languages other than English. Freeman, Housley, & Malpani [Page 73]
