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'CMS') (Obsoleted by RFC 5652) ** Obsolete normative reference: RFC 3281 (Obsoleted by RFC 5755) -- Duplicate reference: RFC3281, mentioned in 'RFC3281-ERR', was also mentioned in 'RFC3281'. ** Obsolete normative reference: RFC 3281 (Obsoleted by RFC 5755) -- Obsolete informational reference (is this intentional?): RFC 2560 (ref. 'OCSP') (Obsoleted by RFC 6960) Summary: 4 errors (**), 0 flaws (~~), 3 warnings (==), 9 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 IETF PKIX WG Stephen Farrell, Trinity College Dublin 2 Internet Draft Russ Housley, Vigil Security 3 Intended Status: Standards Track Sean Turner, IECA 4 Obsoletes: 3281 (once approved) February 18, 2009 5 Expires: August 18, 2009 7 An Internet Attribute Certificate Profile for Authorization 8 draft-ietf-pkix-3281update-04.txt 10 Status of this Memo 12 This Internet-Draft is submitted to IETF in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html 31 This Internet-Draft will expire on August 18, 2009. 33 Copyright Notice 35 Copyright (c) 2009 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents in effect on the date of 40 publication of this document (http://trustee.ietf.org/licenseinfo). 41 Please review these documents carefully, as they describe your rights 42 and restrictions with respect to this document. 44 This document may contain material from IETF Documents or IETF 45 Contributions published or made publicly available before November 46 10, 2008. The person(s) controlling the copyright in some of this 47 material may not have granted the IETF Trust the right to allow 48 modifications of such material outside the IETF Standards Process. 49 Without obtaining an adequate license from the person(s) controlling 50 the copyright in such materials, this document may not be modified 51 outside the IETF Standards Process, and derivative works of it may 52 not be created outside the IETF Standards Process, except to format 53 it for publication as an RFC or to translate it into languages other 54 than English. 56 Abstract 58 This specification defines a profile for the use of X.509 Attribute 59 Certificates in Internet Protocols. Attribute certificates may be 60 used in a wide range of applications and environments covering a 61 broad spectrum of interoperability goals and a broader spectrum of 62 operational and assurance requirements. The goal of this document is 63 to establish a common baseline for generic applications requiring 64 broad interoperability as well as limited special purpose 65 requirements. The profile places emphasis on attribute certificate 66 support for Internet electronic mail, IPSec, and WWW security 67 applications. This document obsoletes RFC 3281. 69 Discussion 71 This draft is being discussed on the 'ietf-pkix' mailing list. To 72 subscribe, send a message to ietf-pkix-request@imc.org with the 73 single word subscribe in the body of the message. There is a Web site 74 for the mailing list at . 76 Table of Contents 78 1. Introduction...................................................3 79 1.1. Requirements Terminology..................................5 80 1.2. AC Path Delegation........................................5 81 1.3. Attribute Certificate Distribution ("push" vs. "pull")....5 82 1.4. Document Structure........................................7 83 2. Terminology....................................................7 84 3. Requirements...................................................8 85 4. Attribute Certificate Profile..................................9 86 4.1. X.509 Attribute Certificate Definition...................10 87 4.2. Profile of Standard Fields...............................12 88 4.2.1. Version.............................................12 89 4.2.2. Holder..............................................12 90 4.2.3. Issuer..............................................14 91 4.2.4. Signature...........................................14 92 4.2.5. Serial Number.......................................14 93 4.2.6. Validity Period.....................................15 94 4.2.7. Attributes..........................................15 95 4.2.8. Issuer Unique Identifier............................16 96 4.2.9. Extensions..........................................16 97 4.3. Extensions...............................................16 98 4.3.1. Audit Identity......................................16 99 4.3.2. AC Targeting........................................17 100 4.3.3. Authority Key Identifier............................19 101 4.3.4. Authority Information Access........................19 102 4.3.5. CRL Distribution Points.............................20 103 4.3.6. No Revocation Available.............................20 104 4.4. Attribute Types..........................................20 105 4.4.1. Service Authentication Information..................21 106 4.4.2. Access Identity.....................................22 107 4.4.3. Charging Identity...................................22 108 4.4.4. Group...............................................22 109 4.4.5. Role................................................23 110 4.4.6. Clearance...........................................23 111 4.5. Profile of AC issuer's PKC...............................26 112 5. Attribute Certificate Validation..............................26 113 6. Revocation....................................................27 114 7. Optional Features.............................................28 115 7.1. Attribute Encryption.....................................29 116 7.2. Proxying.................................................30 117 7.3. Use of ObjectDigestInfo..................................32 118 7.4. AA Controls..............................................33 119 8. Security Considerations.......................................34 120 9. IANA Considerations...........................................36 121 10. References...................................................36 122 10.1. Normative References....................................36 123 10.2. Informative References..................................37 124 Appendix A Object Identifiers....................................38 125 Appendix B ASN.1 Module..........................................39 126 Appendix C Changes Since RFC 3281................................45 127 Author's Addresses...............................................47 129 1. Introduction 131 X.509 public key certificates (PKCs) [X.509-1997, X.509-2000, 132 PKIXPROF] bind an identity and a public key. An attribute 133 certificate (AC) is a structure similar to a PKC; the main difference 134 being that the AC contains no public key. An AC may contain 135 attributes that specify group membership, role, security clearance, 136 or other authorization information associated with the AC holder. 137 The syntax for the AC is defined in Recommendation X.509, making the 138 term "X.509 certificate" ambiguous. 140 Some people constantly confuse PKCs and ACs. An analogy may make the 141 distinction clear. A PKC can be considered to be like a passport: it 142 identifies the holder, tends to last for a long time, and should not 143 be trivial to obtain. An AC is more like an entry visa: it is 144 typically issued by a different authority and does not last for as 145 long a time. As acquiring an entry visa typically requires 146 presenting a passport, getting a visa can be a simpler process. 148 Authorization information may be placed in a PKC extension or placed 149 in a separate attribute certificate (AC). The placement of 150 authorization information in PKCs is usually undesirable for two 151 reasons. First, authorization information often does not have the 152 same lifetime as the binding of the identity and the public key. When 153 authorization information is placed in a PKC extension, the general 154 result is the shortening of the PKC useful lifetime. Second, the PKC 155 issuer is not usually authoritative for the authorization 156 information. This results in additional steps for the PKC issuer to 157 obtain authorization information from the authoritative source. 159 For these reasons, it is often better to separate authorization 160 information from the PKC. Yet, authorization information also needs 161 to be bound to an identity. An AC provides this binding; it is 162 simply a digitally signed (or certified) identity and set of 163 attributes. 165 An AC may be used with various security services, including access 166 control, data origin authentication, and non-repudiation. 168 PKCs can provide an identity to access control decision functions. 169 However, in many contexts the identity is not the criterion that is 170 used for access control decisions, rather the role or group- 171 membership of the accessor is the criterion used. Such access 172 control schemes are called role-based access control. 174 When making an access control decision based on an AC, an access 175 control decision function may need to ensure that the appropriate AC 176 holder is the entity that has requested access. One way in which the 177 linkage between the request or identity and the AC can be achieved is 178 the inclusion of a reference to a PKC within the AC and the use of 179 the private key corresponding to the PKC for authentication within 180 the access request. 182 ACs may also be used in the context of a data origin authentication 183 service and a non-repudiation service. In these contexts, the 184 attributes contained in the AC provide additional information about 185 the signing entity. This information can be used to make sure that 186 the entity is authorized to sign the data. This kind of checking 187 depends either on the context in which the data is exchanged or on 188 the data that has been digitally signed. 190 This document obsoletes [RFC3281]. Changes since [RFC3281] are listed 191 in Appendix C. 193 1.1. Requirements Terminology 195 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 196 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 197 document are to be interpreted as described in [RFC2119]. 199 1.2. AC Path Delegation 201 The X.509 standard [X.509-2000] defines authorization as the 202 "conveyance of privilege from one entity that holds such privilege, 203 to another entity". An AC is one authorization mechanism. 205 An ordered sequence of ACs could be used to verify the authenticity 206 of a privilege asserter's privilege. In this way, chains or paths of 207 ACs could be employed to delegate authorization. 209 Since the administration and processing associated with such AC 210 chains is complex and the use of ACs in the Internet today is quite 211 limited, this specification does NOT RECOMMEND the use of AC chains. 212 Other (future) specifications may address the use of AC chains. This 213 specification deals with the simple cases, where one authority issues 214 all of the ACs for a particular set of attributes. However, this 215 simplification does not preclude the use of several different 216 authorities, each of which manages a different set of attributes. 217 For example, group membership may be included in one AC issued by one 218 authority, and security clearance may be included in another AC 219 issued by another authority. 221 This means that conformant implementations are only REQUIRED to be 222 able to process a single AC at a time. Processing of more than one 223 AC, one after another, may be necessary. Note however, that 224 validation of an AC MAY require validation of a chain of PKCs, as 225 specified in [PKIXPROF]. 227 1.3. Attribute Certificate Distribution ("push" vs. "pull") 229 As discussed above, ACs provide a mechanism to securely provide 230 authorization information to, for example, access control decision 231 functions. However, there are a number of possible communication 232 paths for ACs. 234 In some environments, it is suitable for a client to "push" an AC to 235 a server. This means that no new connections between the client and 236 server are required. It also means that no search burden is imposed 237 on servers, which improves performance and that the AC verifier is 238 only presented with what it "needs to know". The "push" model is 239 especially suitable in inter-domain cases where the client's rights 240 should be assigned within the client's "home" domain. 242 In other cases, it is more suitable for a client to simply 243 authenticate to the server and for the server to request or "pull" 244 the client's AC from an AC issuer or a repository. A major benefit 245 of the "pull" model is that it can be implemented without changes to 246 the client or to the client-server protocol. The "pull" model is 247 especially suitable for inter-domain cases where the client's rights 248 should be assigned within the server's domain, rather than within the 249 client's domain. 251 There are a number of possible exchanges involving three entities: 252 the client, the server, and the AC issuer. In addition, a directory 253 service or other repository for AC retrieval MAY be supported. 255 Figure 1 shows an abstract view of the exchanges that may involve 256 ACs. This profile does not specify a protocol for these exchanges. 258 +--------------+ 259 | | Server Acquisition 260 | AC issuer +----------------------------+ 261 | | | 262 +--+-----------+ | 263 | | 264 | Client | 265 | Acquisition | 266 | | 267 +--+-----------+ +--+------------+ 268 | | AC "push" | | 269 | Client +-------------------------+ Server | 270 | | (part of app. protocol) | | 271 +--+-----------+ +--+------------+ 272 | | 273 | Client | Server 274 | Lookup +--------------+ | Lookup 275 | | | | 276 +---------------+ Repository +---------+ 277 | | 278 +--------------+ 280 Figure 1: AC Exchanges 282 1.4. Document Structure 284 Section 2 defines some terminology. Section 3 specifies the 285 requirements that this profile is intended to meet. Section 4 286 contains the profile of the X.509 AC. Section 5 specifies rules for 287 AC validation. Section 6 specifies rules for AC revocation checks. 288 Section 7 specifies optional features which MAY be supported; 289 however, support for these features is not required for conformance 290 to this profile. Finally, appendices contain the list of OIDs 291 required to support this specification and an ASN.1 module. 293 2. Terminology 295 For simplicity, we use the terms client and server in this 296 specification. This is not intended to indicate that ACs are only to 297 be used in client-server environments. For example, ACs may be used 298 in the S/MIME v3.2 context, where the mail user agent would be both a 299 "client" and a "server" in the sense the terms are used here. 301 Term Meaning 303 AA Attribute Authority, the entity that issues the 304 AC, synonymous in this specification with "AC 305 issuer". 307 AC Attribute Certificate. 309 AC user Any entity that parses or processes an AC. 311 AC verifier Any entity that checks the validity of an AC and 312 then makes use of the result. 314 AC issuer The entity which signs the AC, synonymous in this 315 specification with "AA". 317 AC holder The entity indicated (perhaps indirectly) in the 318 holder field of the AC. 320 Client The entity which is requesting the action for 321 which authorization checks are to be made. 323 Proxying In this specification, Proxying is used to mean 324 the situation where an application server acts as 325 an application client on behalf of a user. 326 Proxying here does not mean granting of authority. 328 PKC Public Key Certificate - uses the ASN.1 type 329 Certificate defined in X.509 and profiled in RFC 330 5280. This (non-standard) acronym is used in order 331 to avoid confusion about the term "X.509 332 certificate". 334 Server The entity which requires that the authorization 335 checks are made. 337 3. Requirements 339 This AC profile meets the following requirements. 341 Time/Validity requirements: 343 1. Support for short-lived as well as long-lived ACs. Typical 344 short-lived validity periods might be measured in hours, as 345 opposed to months for PKCs. Short validity periods allow ACs to 346 be useful without a revocation mechanism. 348 Attribute Types: 350 2. Issuers of ACs should be able to define their own attribute types 351 for use within closed domains. 353 3. Some standard attribute types, which can be contained within ACs, 354 should be defined. Examples include "access identity", "group", 355 "role", "clearance", "audit identity", and "charging identity". 357 4. Standard attribute types should be defined in a manner that 358 permits an AC verifier to distinguish between uses of the same 359 attribute in different domains. For example, the "Administrators 360 group" as defined by Baltimore and the "Administrators group" as 361 defined by SPYRUS should be easily distinguished. 363 Targeting of ACs: 365 5. It should be possible to "target" an AC at one, or a small number 366 of, servers. This means that a trustworthy non-target server will 367 reject the AC for authorization decisions. 369 Push vs. Pull 371 6. ACs should be defined so that they can either be "pushed" by the 372 client to the server, or "pulled" by the server from a repository 373 or other network service, including an online AC issuer. 375 4. Attribute Certificate Profile 377 ACs may be used in a wide range of applications and environments 378 covering a broad spectrum of interoperability goals and a broader 379 spectrum of operational and assurance requirements. The goal of this 380 document is to establish a common baseline for generic applications 381 requiring broad interoperability and limited special purpose 382 requirements. In particular, the emphasis will be on supporting the 383 use of attribute certificates for informal Internet electronic mail, 384 IPSec, and WWW applications. 386 This section presents a profile for ACs that will foster 387 interoperability. This section also defines some private extensions 388 for the Internet community. 390 While the ISO/IEC/ITU documents use the 1993 (or later) version of 391 ASN.1, this document uses the 1988 ASN.1 syntax, as has been done for 392 PKCs [PKIXPROF]. The encoded certificates and extensions from either 393 ASN.1 version are bit-wise identical. 395 Where maximum lengths for fields are specified, these lengths refer 396 to the DER encoding and do not include the ASN.1 tag or length 397 fields. 399 Conforming implementations MUST support the profile specified in this 400 section. 402 4.1. X.509 Attribute Certificate Definition 404 X.509 contains the definition of an AC given below. All types that 405 are not defined in this document can be found in [PKIXPROF]. 407 AttributeCertificate ::= SEQUENCE { 408 acinfo AttributeCertificateInfo, 409 signatureAlgorithm AlgorithmIdentifier, 410 signatureValue BIT STRING 411 } 413 AttributeCertificateInfo ::= SEQUENCE { 414 version AttCertVersion, -- version is v2 415 holder Holder, 416 issuer AttCertIssuer, 417 signature AlgorithmIdentifier, 418 serialNumber CertificateSerialNumber, 419 attrCertValidityPeriod AttCertValidityPeriod, 420 attributes SEQUENCE OF Attribute, 421 issuerUniqueID UniqueIdentifier OPTIONAL, 422 extensions Extensions OPTIONAL 423 } 425 AttCertVersion ::= INTEGER { v2(1) } 427 Holder ::= SEQUENCE { 428 baseCertificateID [0] IssuerSerial OPTIONAL, 429 -- the issuer and serial number of 430 -- the holder's Public Key Certificate 431 entityName [1] GeneralNames OPTIONAL, 432 -- the name of the claimant or role 433 objectDigestInfo [2] ObjectDigestInfo OPTIONAL 434 -- used to directly authenticate the holder, 435 -- for example, an executable 436 } 437 ObjectDigestInfo ::= SEQUENCE { 438 digestedObjectType ENUMERATED { 439 publicKey (0), 440 publicKeyCert (1), 441 otherObjectTypes (2) }, 442 -- otherObjectTypes MUST NOT 443 -- be used in this profile 444 otherObjectTypeID OBJECT IDENTIFIER OPTIONAL, 445 digestAlgorithm AlgorithmIdentifier, 446 objectDigest BIT STRING 447 } 449 AttCertIssuer ::= CHOICE { 450 v1Form GeneralNames, -- MUST NOT be used in this 451 -- profile 452 v2Form [0] V2Form -- v2 only 453 } 455 V2Form ::= SEQUENCE { 456 issuerName GeneralNames OPTIONAL, 457 baseCertificateID [0] IssuerSerial OPTIONAL, 458 objectDigestInfo [1] ObjectDigestInfo OPTIONAL 459 -- issuerName MUST be present in this profile 460 -- baseCertificateID and objectDigestInfo MUST NOT 461 -- be present in this profile 462 } 464 IssuerSerial ::= SEQUENCE { 465 issuer GeneralNames, 466 serial CertificateSerialNumber, 467 issuerUID UniqueIdentifier OPTIONAL 468 } 470 AttCertValidityPeriod ::= SEQUENCE { 471 notBeforeTime GeneralizedTime, 472 notAfterTime GeneralizedTime 473 } 475 Although the Attribute syntax is defined in [PKIXPROF], we repeat the 476 definition here for convenience. 478 Attribute ::= SEQUENCE { 479 type AttributeType, 480 values SET OF AttributeValue 481 -- at least one value is required 482 } 483 AttributeType ::= OBJECT IDENTIFIER 485 AttributeValue ::= ANY DEFINED BY AttributeType 487 Implementers should note that the DER encoding (see [X.509- 488 1988],[X.690]) of the SET OF values requires ordering of the 489 encodings of the values. Though this issue arises with respect to 490 distinguished names, and has to be handled by [PKIXPROF] 491 implementations, it is much more significant in this context, since 492 the inclusion of multiple values is much more common in ACs. 494 4.2. Profile of Standard Fields 496 GeneralName offers great flexibility. To achieve interoperability, 497 in spite of this flexibility, this profile imposes constraints on the 498 use of GeneralName. 500 Conforming implementations MUST be able to support the dNSName, 501 directoryName, uniformResourceIdentifier, and iPAddress options. This 502 is compatible with the GeneralName requirements in [PKIXPROF] (mainly 503 in section 4.2.1.6). 505 Conforming implementations MUST NOT use the x400Address, 506 ediPartyName, or registeredID options. 508 Conforming implementations MAY use the otherName option to convey 509 name forms defined in Internet Standards. For example, Kerberos 510 [KRB] format names can be encoded into the otherName, using a 511 Kerberos 5 principal name OID and a SEQUENCE of the Realm and the 512 PrincipalName. 514 4.2.1. Version 516 The version field MUST have the value of v2. That is, the version 517 field is present in the DER encoding. 519 Note: This version (v2) is not backwards compatible with the previous 520 attribute certificate definition (v1) from the 1997 X.509 standard 521 [X.509-1997], but is compatible with the v2 definition from X.509 522 (2000) [X.509-2000]. 524 4.2.2. Holder 526 The Holder field is a SEQUENCE allowing three different (optional) 527 syntaxes: baseCertificateID, entityName and objectDigestInfo. Where 528 only one option is present, the meaning of the Holder field is clear. 529 However, where more than one option is used, there is a potential for 530 confusion as to which option is "normative", which is a "hint" etc. 531 Since the correct position is not clear from [X.509-2000], this 532 specification RECOMMENDS that only one of the options be used in any 533 given AC. 535 For any environment where the AC is passed in an authenticated 536 message or session and where the authentication is based on the use 537 of an X.509 PKC, the holder field SHOULD use the baseCertificateID. 539 With the baseCertificateID option, the holder's PKC serialNumber and 540 issuer MUST be identical to the AC holder field. The PKC issuer MUST 541 have a non-empty distinguished name which is to be present as the 542 single value of the holder.baseCertificateID.issuer construct in the 543 directoryName field. The AC holder.baseCertificateID.issuerUID field 544 MUST only be used if the holder's PKC contains an issuerUniqueID 545 field. If both the AC holder.baseCertificateID.issuerUID and the PKC 546 issuerUniqueID fields are present, the same value MUST be present in 547 both fields. Thus, the baseCertificateID is only usable with PKC 548 profiles (like [PKIXPROF]) which mandate that the PKC issuer field 549 contain a non-empty distinguished name value. 551 Note: An empty distinguished name is a distinguished name where the 552 SEQUENCE OF relative distinguished names is of zero length. In a DER 553 encoding, this has the value '3000'H. 555 If the holder field uses the entityName option and the underlying 556 authentication is based on a PKC, the entityName MUST be the same as 557 the PKC subject field or one of the values of the PKC subjectAltName 558 field extension (if present). Note that [PKIXPROF] mandates that the 559 subjectAltName extension be present if the PKC subject is an empty 560 distinguished name. See the security considerations section which 561 mentions some name collision problems that may arise when using the 562 entityName option. 564 In any other case where the holder field uses the entityName option, 565 only one name SHOULD be present. 567 Implementations conforming to this profile are not required to 568 support the use of the objectDigest field. However, section 7.3 569 specifies how this optional feature MAY be used. 571 Any protocol conforming to this profile SHOULD specify which AC 572 holder option is to be used and how this fits with the supported 573 authentication schemes defined in that protocol. 575 4.2.3. Issuer 577 ACs conforming to this profile MUST use the v2Form choice, which MUST 578 contain one and only one GeneralName in the issuerName, which MUST 579 contain a non-empty distinguished name in the directoryName field. 580 This means that all AC issuers MUST have non-empty distinguished 581 names. ACs conforming to this profile MUST omit the 582 baseCertificateID and objectDigestInfo fields. 584 Part of the reason for the use of the v2Form containing only an 585 issuerName is that it means that the AC issuer does not have to know 586 which PKC the AC verifier will use for it (the AC issuer). Using the 587 baseCertificateID field to reference the AC issuer would mean that 588 the AC verifier would have to trust the PKC that the AC issuer chose 589 (for itself) at AC creation time. 591 4.2.4. Signature 593 Contains the algorithm identifier used to validate the AC signature. 595 This MUST be one of the signing algorithms defined in [PKIXALGS] or 596 defined in any IETF-approved update to [PKIXALGS]. Conforming 597 implementations MUST honor all MUST/SHOULD/MAY signing algorithm 598 statements specified in [PKIXALGS] or IETF-approved updates to 599 [PKIXALGS]. 601 4.2.5. Serial Number 603 For any conforming AC, the issuer/serialNumber pair MUST form a 604 unique combination, even if ACs are very short-lived. 606 AC issuers MUST force the serialNumber to be a positive integer, that 607 is, the sign bit in the DER encoding of the INTEGER value MUST be 608 zero - this can be done by adding a leading (leftmost) '00'H octet if 609 necessary. This removes a potential ambiguity in mapping between a 610 string of octets and an integer value. 612 Given the uniqueness and timing requirements above, serial numbers 613 can be expected to contain long integers. AC users MUST be able to 614 handle serialNumber values longer than 4 octets. Conformant ACs MUST 615 NOT contain serialNumber values longer than 20 octets. 617 There is no requirement that the serial numbers used by any AC issuer 618 follow any particular ordering. In particular, they need not be 619 monotonically increasing with time. Each AC issuer MUST ensure that 620 each AC that it issues contains a unique serial number. 622 4.2.6. Validity Period 624 The attrCertValidityPeriod (a.k.a. validity) field specifies the 625 period for which the AC issuer certifies that the binding between the 626 holder and the attributes fields will be valid. 628 The generalized time type, GeneralizedTime, is a standard ASN.1 type 629 for variable precision representation of time. The GeneralizedTime 630 field can optionally include a representation of the time 631 differential between the local time zone and Greenwich Mean Time. 633 For the purposes of this profile, GeneralizedTime values MUST be 634 expressed in Coordinated universal time (UTC) (also known as 635 Greenwich Mean Time or Zulu)) and MUST include seconds (i.e., times 636 are YYYYMMDDHHMMSSZ), even when the number of seconds is zero. 637 GeneralizedTime values MUST NOT include fractional seconds. 639 (Note: this is the same as specified in [PKIXPROF], section 640 4.1.2.5.2.) 642 AC users MUST be able to handle an AC which, at the time of 643 processing, has parts of its validity period or all its validity 644 period in the past or in the future (a post-dated AC). This is valid 645 for some applications, such as backup. 647 4.2.7. Attributes 649 The attributes field gives information about the AC holder. When the 650 AC is used for authorization, this will often contain a set of 651 privileges. 653 The attributes field contains a SEQUENCE OF Attribute. Each 654 Attribute contains the type of the attribute and a SET OF values. 655 For a given AC, each AttributeType OBJECT IDENTIFIER in the sequence 656 MUST be unique. That is, only one instance of each attribute can 657 occur in a single AC, but each instance can be multi-valued. 659 AC users MUST be able to handle multiple values for all attribute 660 types. 662 An AC MUST contain at least one attribute. That is, the SEQUENCE OF 663 Attributes MUST NOT be of zero length. 665 Some standard attribute types are defined in section 4.4. 667 4.2.8. Issuer Unique Identifier 669 This field MUST NOT be used unless it is also used in the AC issuer's 670 PKC, in which case it MUST be used. Note that [PKIXPROF] states that 671 this field SHOULD NOT be used by conforming CAs, but that 672 applications SHOULD be able to parse PKCs containing the field. 674 4.2.9. Extensions 676 The extensions field generally gives information about the AC as 677 opposed to information about the AC holder. 679 An AC that has no extensions conforms to the profile; however, 680 section 4.3 defines the extensions that MAY be used with this 681 profile, and whether or not they may be marked critical. If any 682 other critical extension is used, the AC does not conform to this 683 profile. However, if any other non-critical extension is used, the 684 AC does conform to this profile. 686 The extensions defined for ACs provide methods for associating 687 additional attributes with holders. This profile also allows 688 communities to define private extensions to carry information unique 689 to those communities. Each extension in an AC may be designated as 690 critical or non-critical. An AC using system MUST reject an AC if it 691 encounters a critical extension it does not recognize; however, a 692 non-critical extension may be ignored if it is not recognized. 693 Section 4.3 presents recommended extensions used within Internet ACs 694 and standard locations for information. Communities may elect to use 695 additional extensions; however, caution should be exercised in 696 adopting any critical extensions in ACs which might prevent use in a 697 general context. 699 4.3. Extensions 701 4.3.1. Audit Identity 703 In some circumstances, it is required (e.g. by data protection/data 704 privacy legislation) that audit trails not contain records which 705 directly identify individuals. This circumstance may make the use of 706 the AC holder field unsuitable for use in audit trails. 708 To allow for such cases, an AC MAY contain an audit identity 709 extension. Ideally it SHOULD be infeasible to derive the AC holder's 710 identity from the audit identity value without the cooperation of the 711 AC issuer. 713 The value of the audit identity, along with the AC issuer/serial, 714 SHOULD then be used for audit/logging purposes. If the value of the 715 audit identity is suitably chosen, a server/service administrator can 716 use audit trails to track the behavior of an AC holder without being 717 able to identify the AC holder. 719 The server/service administrator in combination with the AC issuer 720 MUST be able to identify the AC holder in cases where misbehavior is 721 detected. This means that the AC issuer MUST be able to determine 722 the actual identity of the AC holder from the audit identity. 724 Of course, auditing could be based on the AC issuer/serial pair; 725 however, this method does not allow tracking of the same AC holder 726 with multiple ACs. Thus, an audit identity is only useful if it 727 lasts for longer than the typical AC lifetime. Auditing could also 728 be based on the AC holder's PKC issuer/serial; however, this will 729 often allow the server/service administrator to identify the AC 730 holder. 732 As the AC verifier might otherwise use the AC holder or some other 733 identifying value for audit purposes, this extension MUST be critical 734 when used. 736 Protocols that use ACs will often expose the identity of the AC 737 holder in the bits on-the-wire. In such cases, an opaque audit 738 identity does not make use of the AC anonymous; it simply ensures 739 that the ensuing audit trails do not contain identifying information. 741 The value of an audit identity MUST be longer than zero octets. The 742 value of an audit identity MUST NOT be longer than 20 octets. 744 name id-pe-ac-auditIdentity 745 OID { id-pe 4 } 746 syntax OCTET STRING 747 criticality MUST be TRUE 749 4.3.2. AC Targeting 751 To target an AC, the target information extension, imported from 752 [X.509-2000], MAY be used to specify a number of servers/services. 753 The intent is that the AC SHOULD only be usable at the specified 754 servers/services. An (honest) AC verifier who is not amongst the 755 named servers/services MUST reject the AC. 757 If this extension is not present, the AC is not targeted and may be 758 accepted by any server. 760 In this profile, the targeting information simply consists of a list 761 of named targets or groups. 763 The following syntax is used to represent the targeting information: 765 Targets ::= SEQUENCE OF Target 767 Target ::= CHOICE { 768 targetName [0] GeneralName, 769 targetGroup [1] GeneralName, 770 targetCert [2] TargetCert 771 } 773 TargetCert ::= SEQUENCE { 774 targetCertificate IssuerSerial, 775 targetName GeneralName OPTIONAL, 776 certDigestInfo ObjectDigestInfo OPTIONAL 777 } 779 The targetCert CHOICE within the Target structure is only present to 780 allow future compatibility with [X.509-2000] and MUST NOT be used. 782 The targets check passes if the current server (recipient) is one of 783 the targetName fields in the Targets SEQUENCE, or if the current 784 server is a member of one of the targetGroup fields in the Targets 785 SEQUENCE. In this case, the current server is said to "match" the 786 targeting extension. 788 How the membership of a target within a targetGroup is determined is 789 not defined here. It is assumed that any given target "knows" the 790 names of the targetGroups to which it belongs or can otherwise 791 determine its membership. For example, the targetGroup specifies a 792 DNS domain, and the AC verifier knows the DNS domain to which it 793 belongs. For another example, the targetGroup specifies "PRINTERS", 794 and the AC verifier knows whether or not it is a printer or print 795 server. 797 Note: [X.509-2000] defines the extension syntax as a "SEQUENCE OF 798 Targets". Conforming AC issuer implementations MUST only produce one 799 "Targets" element. Conforming AC users MUST be able to accept a 800 "SEQUENCE OF Targets". If more than one Targets element is found in 801 an AC, the extension MUST be treated as if all Target elements had 802 been found within one Targets element. 804 name id-ce-targetInformation 805 OID { id-ce 55 } 806 syntax SEQUENCE OF Targets 807 criticality MUST be TRUE 809 4.3.3. Authority Key Identifier 811 The authorityKeyIdentifier extension, as profiled in [PKIXPROF], MAY 812 be used to assist the AC verifier in checking the signature of the 813 AC. The [PKIXPROF] description should be read as if "CA" meant "AC 814 issuer". As with PKCs, this extension SHOULD be included in ACs. 816 Note: An AC, where the issuer field used the baseCertificateID 817 CHOICE, would not need an authorityKeyIdentifier extension, as it is 818 explicitly linked to the key in the referred certificate. However, 819 as this profile states (in section 4.2.3), ACs MUST use the v2Form 820 with issuerName CHOICE, this duplication does not arise. 822 name id-ce-authorityKeyIdentifier 823 OID { id-ce 35 } 824 syntax AuthorityKeyIdentifier 825 criticality MUST be FALSE 827 4.3.4. Authority Information Access 829 The authorityInformationAccess extension, as defined in [PKIXPROF], 830 MAY be used to assist the AC verifier in checking the revocation 831 status of the AC. Support for the id-ad-caIssuers accessMethod is 832 NOT REQUIRED by this profile since AC chains are not expected. 834 The following accessMethod is used to indicate that revocation status 835 checking is provided for this AC, using the OCSP protocol defined in 836 [OCSP]: 838 id-ad-ocsp OBJECT IDENTIFIER ::= { id-ad 1 } 840 The accessLocation MUST contain a URI, and the URI MUST contain an 841 HTTP URL [HTTP-URL] that specifies the location of an OCSP responder. 842 The AC issuer MUST, of course, maintain an OCSP responder at this 843 location. 845 name id-ce-authorityInfoAccess 846 OID { id-pe 1 } 847 syntax AuthorityInfoAccessSyntax 848 criticality MUST be FALSE 850 4.3.5. CRL Distribution Points 852 The crlDistributionPoints extension, as profiled in [PKIXPROF], MAY 853 be used to assist the AC verifier in checking the revocation status 854 of the AC. See section 6 for details on revocation. 856 If the crlDistributionPoints extension is present, then exactly one 857 distribution point MUST be present. The crlDistributionPoints 858 extension MUST use the DistributionPointName option, which MUST 859 contain a fullName, which MUST contain a single name form. That name 860 MUST contain either a distinguished name or a URI. The URI MUST be 861 either an HTTP URL [HTTP-URL] or an LDAP URL [LDAP-URL]. 863 name id-ce-cRLDistributionPoints 864 OID { id-ce 31 } 865 syntax CRLDistributionPoints 866 criticality MUST be FALSE 868 4.3.6. No Revocation Available 870 The noRevAvail extension, defined in [X.509-2000], allows an AC 871 issuer to indicate that no revocation information will be made 872 available for this AC. 874 This extension MUST be non-critical. An AC verifier that does not 875 understand this extension might be able to find a revocation list 876 from the AC issuer, but the revocation list will never include an 877 entry for the AC. 879 name id-ce-noRevAvail 880 OID { id-ce 56 } 881 syntax NULL (i.e. '0500'H is the DER encoding) 882 criticality MUST be FALSE 884 4.4. Attribute Types 886 Some of the attribute types defined below make use of the 887 IetfAttrSyntax type, also defined below. The reasons for using this 888 type are: 890 1. It allows a separation between the AC issuer and the attribute 891 policy authority. This is useful for situations where a single 892 policy authority (e.g. an organization) allocates attribute 893 values, but where multiple AC issuers are deployed for performance 894 or other reasons. 896 2. The syntaxes allowed for values are restricted to OCTET STRING, 897 OBJECT IDENTIFIER, and UTF8String, which significantly reduces the 898 complexity associated with matching more general syntaxes. All 899 multi-valued attributes using this syntax are restricted so that 900 each value MUST use the same choice of value syntax. For example, 901 AC issuers must not use one value with an oid and a second value 902 with a string. 904 IetfAttrSyntax ::= SEQUENCE { 905 policyAuthority [0] GeneralNames OPTIONAL, 906 values SEQUENCE OF CHOICE { 907 octets OCTET STRING, 908 oid OBJECT IDENTIFIER, 909 string UTF8String 910 } 911 } 913 In the descriptions below, each attribute type is either tagged 914 "Multiple Allowed" or "One Attribute value only; multiple values 915 within the IetfAttrSyntax". This refers to the SET OF 916 AttributeValues; the AttributeType still only occurs once, as 917 specified in section 4.2.7. 919 4.4.1. Service Authentication Information 921 The SvceAuthInfo attribute identifies the AC holder to the 922 server/service by a name, and the attribute MAY include optional 923 service specific authentication information. Typically this will 924 contain a username/password pair for a "legacy" application. 926 This attribute provides information that can be presented by the AC 927 verifier to be interpreted and authenticated by a separate 928 application within the target system. Note that this is a different 929 use to that intended for the accessIdentity attribute in 4.4.2 below. 931 This attribute type will typically be encrypted when the authInfo 932 field contains sensitive information, such as a password (see Section 933 7.1). 935 name id-aca-authenticationInfo 936 OID { id-aca 1 } 937 Syntax SvceAuthInfo 938 values: Multiple allowed 940 SvceAuthInfo ::= SEQUENCE { 941 service GeneralName, 942 ident GeneralName, 943 authInfo OCTET STRING OPTIONAL 944 } 946 4.4.2. Access Identity 948 The accessIdentity attribute identifies the AC holder to the 949 server/service. For this attribute the authInfo field MUST NOT be 950 present. 952 This attribute is intended to be used to provide information about 953 the AC holder, that can be used by the AC verifier (or a larger 954 system of which the AC verifier is a component) to authorize the 955 actions of the AC holder within the AC verifier's system. Note that 956 this is a different use to that intended for the svceAuthInfo 957 attribute described in 4.4.1 above. 959 name id-aca-accessIdentity 960 OID { id-aca 2 } 961 syntax SvceAuthInfo 962 values: Multiple allowed 964 4.4.3. Charging Identity 966 The chargingIdentity attribute identifies the AC holder for charging 967 purposes. In general, the charging identity will be different from 968 other identities of the holder. For example, the holder's company 969 may be charged for service. 971 name id-aca-chargingIdentity 972 OID { id-aca 3 } 973 syntax IetfAttrSyntax 974 values: One Attribute value only; multiple values within the 975 IetfAttrSyntax 977 4.4.4. Group 979 The group attribute carries information about group memberships of 980 the AC holder. 982 name id-aca-group 983 OID { id-aca 4 } 984 syntax IetfAttrSyntax 985 values: One Attribute value only; multiple values within the 986 IetfAttrSyntax 988 4.4.5. Role 990 The role attribute, specified in [X.509-2000], carries information 991 about role allocations of the AC holder. 993 The syntax used for this attribute is: 995 RoleSyntax ::= SEQUENCE { 996 roleAuthority [0] GeneralNames OPTIONAL, 997 roleName [1] GeneralName 998 } 1000 The roleAuthority field MAY be used to specify the issuing authority 1001 for the role specification certificate. There is no requirement that 1002 a role specification certificate necessarily exists for the 1003 roleAuthority. This differs from [X.500-2000], where the 1004 roleAuthority field is assumed to name the issuer of a role 1005 specification certificate. For example, to distinguish the 1006 administrator role as defined by "Baltimore" from that defined by 1007 "SPYRUS", one could put the value "urn:administrator" in the roleName 1008 field and the value "Baltimore" or "SPYRUS" in the roleAuthority 1009 field. 1011 The roleName field MUST be present, and roleName MUST use the 1012 uniformResourceIdentifier CHOICE of the GeneralName. 1014 name id-at-role 1015 OID { id-at 72 } 1016 syntax RoleSyntax 1017 values: Multiple allowed 1019 4.4.6. Clearance 1021 The clearance attribute, specified in [X.501-1993], carries clearance 1022 (associated with security labeling) information about the AC holder. 1024 The policyId field is used to identify the security policy to which 1025 the clearance relates. The policyId indicates the semantics of the 1026 classList and securityCategories fields. 1028 This specification includes the classList field exactly as it is 1029 specified in [X.501-1993]. Additional security classification 1030 values, and their position in the classification hierarchy, may be 1031 defined by a security policy as a local matter or by bilateral 1032 agreement. The basic security classification hierarchy is, in 1033 ascending order: unmarked, unclassified, restricted, confidential, 1034 secret, and top-secret. 1036 An organization can develop its own security policy that defines 1037 security classification values and their meanings. However, the BIT 1038 STRING positions 0 through 5 are reserved for the basic security 1039 classification hierarchy. 1041 If present, the SecurityCategory field provides further authorization 1042 information. The security policy identified by the policyId field 1043 indicates the syntaxes that are allowed to be present in the 1044 securityCategories SET. An OBJECT IDENTIFIER identifies each of the 1045 allowed syntaxes. When one of these syntaxes is present in the 1046 securityCategories SET, the OBJECT IDENTIFIER associated with that 1047 syntax is carried in the SecurityCategory.type field. 1049 The object identifier for the clearance attribute from [RFC3281] is: 1051 id-at-clearance OBJECT IDENTIFIER ::= { 1052 joint-iso-ccitt(2) ds(5) module(1) selected-attribute-types(5) 1053 clearance (55) } 1055 The associated syntax was originally (and erroneously) defined in 1056 [RFC3281] as: 1058 Clearance ::= SEQUENCE { 1059 policyId [0] OBJECT IDENTIFIER, 1060 classList [1] ClassList DEFAULT {unclassified}, 1061 securityCategories [2] SET OF SecurityCategory OPTIONAL 1062 } 1064 But, it was later corrected (to restore conformance with X.509) to: 1066 Clearance ::= SEQUENCE { 1067 policyId OBJECT IDENTIFIER, 1068 classList ClassList DEFAULT {unclassified}, 1069 securityCategories SET OF SecurityCategory OPTIONAL 1070 } 1072 The object identifier for the clearance attribute from [X.509-1997] 1073 is: 1075 id-at-clearance OBJECT IDENTIFIER ::= { 1076 joint-iso-ccitt(2) ds(5) attributeType(4) clearance (55) } 1078 The associated syntax is as follows: 1080 Clearance ::= SEQUENCE { 1081 policyId OBJECT IDENTIFIER, 1082 classList ClassList DEFAULT {unclassified}, 1083 securityCategories SET OF SecurityCategory OPTIONAL 1084 } 1086 Implementations MUST support the clearance attribute as defined in 1087 [X.501-1997]. Implementations SHOULD support decoding the clearance 1088 syntax from [RFC3281] and the errata against it [RFC3281-ERR]. 1089 Implementations MUST NOT output the clearance attribute as defined in 1090 [RFC3281]. 1092 ClassList ::= BIT STRING { 1093 unmarked (0), 1094 unclassified (1), 1095 restricted (2), 1096 confidential (3), 1097 secret (4), 1098 topSecret (5) 1099 } 1101 SecurityCategory ::= SEQUENCE { 1102 type [0] OBJECT IDENTIFIER, 1103 value [1] EXPLICIT ANY DEFINED BY type 1104 } 1106 -- Note that in [RFC3281] the SecurityCategory syntax was as 1107 -- follows: 1108 -- 1109 -- SecurityCategory ::= SEQUENCE { 1110 -- type [0] IMPLICIT OBJECT IDENTIFIER, 1111 -- value [1] ANY DEFINED BY type 1112 -- } 1113 -- 1114 -- The removal of the IMPLICIT from the type line and the 1115 -- addition of the EXPLICIT to the value line result in 1116 -- no changes to the encodings. 1118 -- This is the same as the original syntax which was defined 1119 -- using the MACRO construct, as follows: 1120 -- SecurityCategory ::= SEQUENCE { 1121 -- type [0] IMPLICIT SECURITY-CATEGORY, 1122 -- value [1] ANY DEFINED BY type 1123 -- } 1124 -- 1125 -- SECURITY-CATEGORY MACRO ::= 1126 -- BEGIN 1127 -- TYPE NOTATION ::= type | empty 1128 -- VALUE NOTATION ::= value (VALUE OBJECT IDENTIFIER) 1129 -- END 1131 name { id-at-clearance } 1132 OID { joint-iso-ccitt(2) ds(5) attribute-type (4) 1133 clearance (55) } 1134 syntax Clearance -- imported from [X.501-1997] 1135 values Multiple allowed 1137 4.5. Profile of AC issuer's PKC 1139 The AC issuer's PKC MUST conform to [PKIXPROF], and the keyUsage 1140 extension in the PKC MUST NOT explicitly indicate that the AC 1141 issuer's public key cannot be used to validate a digital signature. 1142 In order to avoid confusion regarding serial numbers and revocations, 1143 an AC issuer MUST NOT also be a PKC Issuer. That is, an AC issuer 1144 cannot be a CA as well. So, the AC issuer's PKC MUST NOT have a 1145 basicConstraints extension with the cA BOOLEAN set to TRUE. 1147 5. Attribute Certificate Validation 1149 This section describes a basic set of rules that all valid ACs MUST 1150 satisfy. Some additional checks are also described which AC 1151 verifiers MAY choose to implement. 1153 To be valid an AC MUST satisfy all of the following: 1155 1. Where the holder uses a PKC to authenticate to the AC verifier, 1156 the AC holder's PKC MUST be found, and the entire certification 1157 path of that PKC MUST be verified in accordance with [PKIXPROF]. 1158 As noted in the security considerations section, if some other 1159 authentication scheme is used, AC verifiers need to be very 1160 careful mapping the identities (authenticated identity, holder 1161 field) involved. 1163 2. The AC signature must be cryptographically correct, and the AC 1164 issuer's entire PKC certification path MUST be verified in 1165 accordance with [PKIXPROF]. 1167 3. The AC issuer's PKC MUST also conform to the profile specified in 1168 section 4.5 above. 1170 4. The AC issuer MUST be directly trusted as an AC issuer (by 1171 configuration or otherwise). 1173 5. The time for which the AC is being evaluated MUST be within the AC 1174 validity. If the evaluation time is equal to either notBeforeTime 1175 or notAfterTime, then the AC is timely and this check succeeds. 1176 Note that in some applications, the evaluation time MAY not be the 1177 same as the current time. 1179 6. The AC targeting check MUST pass as specified in section 4.3.2. 1181 7. If the AC contains an unsupported critical extension, the AC MUST 1182 be rejected. 1184 Support for an extension in this context means: 1186 1. The AC verifier MUST be able to parse the extension value. 1188 2. Where the extension value SHOULD cause the AC to be rejected, the 1189 AC verifier MUST reject the AC. 1191 Additional Checks: 1193 1. The AC MAY be rejected on the basis of further AC verifier 1194 configuration. For example, an AC verifier may be configured to 1195 reject ACs which contain or lack certain attributes. 1197 2. If the AC verifier provides an interface that allows applications 1198 to query the contents of the AC, then the AC verifier MAY filter 1199 the attributes from the AC on the basis of configured information. 1200 For example, an AC verifier might be configured not to return 1201 certain attributes to certain servers. 1203 6. Revocation 1205 In many environments, the validity period of an AC is less than the 1206 time required to issue and distribute revocation information. 1207 Therefore, short-lived ACs typically do not require revocation 1208 support. However, long-lived ACs and environments where ACs enable 1209 high value transactions MAY require revocation support. 1211 Two revocation schemes are defined, and the AC issuer should elect 1212 the one that is best suited to the environment in which the AC will 1213 be employed. 1215 "Never revoke" scheme: 1217 ACs may be marked so that the relying party understands that no 1218 revocation status information will be made available. The 1219 noRevAvail extension is defined in section 4.3.6, and the 1220 noRevAvail extension MUST be present in the AC to indicate use of 1221 this scheme. 1223 Where no noRevAvail is present, the AC issuer is implicitly stating 1224 that revocation status checks are supported, and some revocation 1225 method MUST be provided to allow AC verifiers to establish the 1226 revocation status of the AC. 1228 "Pointer in AC" scheme: 1230 ACs may "point" to sources of revocation status information, using 1231 either an authorityInfoAccess extension or a crlDistributionPoints 1232 extension within the AC. 1234 For AC users, the "never revoke" scheme MUST be supported, and the 1235 "pointer in AC" scheme SHOULD be supported. If only the "never 1236 revoke" scheme is supported, then all ACs that do not contain a 1237 noRevAvail extension, MUST be rejected. 1239 For AC issuers, the "never revoke" scheme MUST be supported. If all 1240 ACs that will ever be issued by that AC issuer contain a noRevAvail 1241 extension, the "pointer in AC" scheme need not be supported. If any 1242 AC can be issued that does not contain the noRevAvail extension, the 1243 "pointer in AC" scheme MUST be supported. 1245 An AC MUST NOT contain both a noRevAvail and a "pointer in AC". 1247 An AC verifier MAY use any source for AC revocation status 1248 information. 1250 7. Optional Features 1252 This section specifies features that MAY be implemented. Conformance 1253 to this profile does NOT require support for these features; however, 1254 if these features are offered, they MUST be offered as described 1255 below. 1257 7.1. Attribute Encryption 1259 Where an AC will be carried in clear within an application protocol 1260 or where an AC contains some sensitive information like a legacy 1261 application username/password, then encryption of AC attributes MAY 1262 be needed. 1264 When a set of attributes is to be encrypted within an AC, the 1265 Cryptographic Message Syntax, EnvelopedData structure [CMS] is used 1266 to carry the ciphertext and associated per-recipient keying 1267 information. 1269 This type of attribute encryption is targeted. Before the AC is 1270 signed, the attributes are encrypted for a set of predetermined 1271 recipients. 1273 Within EnvelopedData, the encapsulatedContentInfo identifies the 1274 content type carried withing the ciphertext. In this case, the 1275 contentType field of encapsulatedContentInfo MUST contain id-ct- 1276 attrCertEncAttrs, which has the following value: 1278 attrCertEncAttrs OBJECT IDENTIFIER ::= { 1279 iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) 1280 id-smime(16) id-ct(1) 14 } 1282 The ciphertext is included in the AC as the value of an encAttrs 1283 attribute. Only one encAttrs attribute can be present in an AC; 1284 however, the encAttrs attribute MAY be multi-valued, and each of its 1285 values will contain an independent EnvelopedData. 1287 Each value can contain a set of attributes (each possibly a multi- 1288 valued attribute) encrypted for a set of predetermined recipients. 1290 The cleartext that is encrypted has the type: 1292 ACClearAttrs ::= SEQUENCE { 1293 acIssuer GeneralName, 1294 acSerial INTEGER, 1295 attrs SEQUENCE OF Attribute 1296 } 1298 The DER encoding of the ACClearAttrs structure is used as the 1299 encryptedContent field of the EnvelopedData. The DER encoding MUST 1300 be embedded in an OCTET STRING. 1302 The acIssuer and acSerial fields are present to prevent ciphertext 1303 stealing. When an AC verifier has successfully decrypted an 1304 encrypted attribute, it MUST then check that the AC issuer and 1305 serialNumber fields contain the same values. This prevents a 1306 malicious AC issuer from copying ciphertext from another AC (without 1307 knowing its corresponding plaintext). 1309 The procedure for an AC issuer when encrypting attributes is 1310 illustrated by the following (any other procedure that gives the same 1311 result MAY be used): 1313 1. Identify the sets of attributes that are to be encrypted for 1314 each set of recipients. 1315 2. For each attribute set which is to be encrypted: 1316 2.1. Create an EnvelopedData structure for the data for this 1317 set of recipients. 1318 2.2. Encode the ContentInfo containing the EnvelopedData as a 1319 value of the encAttrs attribute. 1320 2.3. Ensure the cleartext attributes are not present in the 1321 to-be-signed AC. 1322 3. Add the encAttrs (with its multiple values) to the AC. 1324 Note that there may be more than one attribute of the same type (the 1325 same OBJECT IDENTIFIER) after decryption. That is, an AC MAY contain 1326 the same attribute type both in clear and in encrypted form (and 1327 indeed several times if the same recipient is associated with more 1328 than one EnvelopedData). One approach implementers may choose, would 1329 be to merge attribute values following decryption in order to re- 1330 establish the "once only" constraint. 1332 name id-aca-encAttrs 1333 OID { id-aca 6} 1334 Syntax ContentInfo 1335 values Multiple Allowed 1337 If an AC contains attributes apparently encrypted for the AC 1338 verifier, then the decryption process failure MUST cause the AC to be 1339 rejected. 1341 7.2. Proxying 1343 When a server acts as a client for another server on behalf of the AC 1344 holder, the server MAY need to proxy an AC. Such proxying MAY have 1345 to be done under the AC issuer's control, so that not every AC is 1346 proxiable and so that a given proxiable AC can be proxied in a 1347 targeted fashion. Support for chains of proxies (with more than one 1348 intermediate server) MAY also be required. Note that this does not 1349 involve a chain of ACs. 1351 In order to meet this requirement we define another extension, 1352 ProxyInfo, similar to the targeting extension. 1354 When this extension is present, the AC verifier must check that the 1355 entity from which the AC was received was allowed to send it and that 1356 the AC is allowed to be used by this verifier. 1358 The proxying information consists of a list of proxy information, 1359 each of which is a list of targeting information. If the verifier 1360 and the sender of the AC are both named in the same proxy list, the 1361 AC can then be accepted (the exact rule is given below). 1363 The effect is that the AC holder can send the AC to any valid target 1364 which can then only proxy to targets which are in one of the same 1365 proxy lists as itself. 1367 The following data structure is used to represent the 1368 targeting/proxying information. 1370 ProxyInfo ::= SEQUENCE OF Targets 1372 Targets is explained in Section 4.3.2. As in the case of targeting, 1373 the targetCert CHOICE MUST NOT be used. 1375 A proxy check succeeds if either one of the conditions below is met: 1377 1. The identity of the sender, as established by the underlying 1378 authentication service, matches the holder field of the AC, and 1379 the current server "matches" any one of the proxy sets. Recall 1380 that "matches" is as defined section 4.3.2. 1382 2. The identity of the sender, as established by the underlying 1383 authentication service, "matches" one of the proxy sets (call it 1384 set "A"), and the current server is one of the targetName fields 1385 in the set "A", or the current server is a member of one of the 1386 targetGroup fields in set "A". 1388 When an AC is proxied more than once, a number of targets will be on 1389 the path from the original client, which is normally, but not always, 1390 the AC holder. In such cases, prevention of AC "stealing" requires 1391 that the AC verifier MUST check that all targets on the path are 1392 members of the same proxy set. It is the responsibility of the AC- 1393 using protocol to ensure that a trustworthy list of targets on the 1394 path is available to the AC verifier. 1396 name id-pe-ac-proxying 1397 OID { id-pe 10 } 1398 syntax ProxyInfo 1399 criticality MUST be TRUE 1401 7.3. Use of ObjectDigestInfo 1403 In some environments, it may be required that the AC is not linked 1404 either to an identity (via entityName) or to a PKC (via 1405 baseCertificateID). The objectDigestInfo CHOICE in the holder field 1406 allows support for this requirement. 1408 If the holder is identified with the objectDigestInfo field, then the 1409 AC version field MUST contain v2 (the integer 1). 1411 The idea is to link the AC to an object by placing a hash of that 1412 object into the holder field of the AC. For example, this allows 1413 production of ACs that are linked to public keys rather than names. 1414 It also allows production of ACs which contain privileges associated 1415 with an executable object such as a Java class. However, this 1416 profile only specifies how to use a hash over a public key or PKC. 1417 That is, conformant ACs MUST NOT use the otherObjectTypes value for 1418 the digestedObjectType. 1420 To link an AC to a public key, the hash must be calculated over the 1421 representation of that public key which would be present in a PKC, 1422 specifically, the input for the hash algorithm MUST be the DER 1423 encoding of a SubjectPublicKeyInfo representation of the key. Note: 1424 This includes the AlgorithmIdentifier as well as the BIT STRING. The 1425 rules given in [PKIXPROF] for encoding keys MUST be followed. In 1426 this case, the digestedObjectType MUST be publicKey and the 1427 otherObjectTypeID field MUST NOT be present. 1429 Note that if the public key value used as input to the hash function 1430 has been extracted from a PKC, it is possible that the 1431 SubjectPublicKeyInfo from that PKC is NOT the value which should be 1432 hashed. This can occur if DSA Dss-parms are inherited as described 1433 in section 7.3.3 of [PKIXPROF]. The correct input for hashing in 1434 this context will include the value of the parameters inherited from 1435 the CA's PKC, and thus may differ from the SubjectPublicKeyInfo 1436 present in the PKC. 1438 Implementations which support this feature MUST be able to handle the 1439 representations of public keys for the algorithms specified in 1440 section 7.3 of [PKIXPROF]. 1442 In order to link an AC to a PKC via a digest, the digest MUST be 1443 calculated over the DER encoding of the entire PKC, including the 1444 signature value. In this case the digestedObjectType MUST be 1445 publicKeyCert and the otherObjectTypeID field MUST NOT be present. 1447 7.4. AA Controls 1449 During AC validation a relying party has to answer the question: is 1450 this AC issuer trusted to issue ACs containing this attribute? The 1451 AAControls PKC extension MAY be used to help answer the question. The 1452 AAControls extension is intended to be used in CA and AC issuer PKCs. 1454 id-pe-aaControls OBJECT IDENTIFIER ::= { id-pe 6 } 1456 AAControls ::= SEQUENCE { 1457 pathLenConstraint INTEGER (0..MAX) OPTIONAL, 1458 permittedAttrs [0] AttrSpec OPTIONAL, 1459 excludedAttrs [1] AttrSpec OPTIONAL, 1460 permitUnSpecified BOOLEAN DEFAULT TRUE 1461 } 1463 AttrSpec::= SEQUENCE OF OBJECT IDENTIFIER 1465 The AAControls extension is used as follows: 1467 The pathLenConstraint, if present, is interpreted as in [PKIXPROF]. 1468 It restricts the allowed distance between the AA CA (a CA directly 1469 trusted to include AAControls in its PKCs), and the AC issuer. 1471 The permittedAttrs field specifies a list of attribute types that any 1472 AC issuer below this AA CA is allowed to include in ACs. If this 1473 field is not present, it means that no attribute types are explicitly 1474 allowed. 1476 The excludedAttrs field specifies a list of attribute types that no 1477 AC issuer below this AA CA is allowed to include in ACs. If this 1478 field is not present, it means that no attribute types are explicitly 1479 disallowed. 1481 The permitUnSpecified field specifies how to handle attribute types 1482 which are not present in either the permittedAttrs or excludedAttrs 1483 fields. TRUE (the default) means that any unspecified attribute type 1484 is allowed in ACs; FALSE means that no unspecified attribute type is 1485 allowed. 1487 When AAControls are used, the following additional checks on an AA's 1488 PKC chain MUST all succeed for the AC to be valid: 1490 1. Some CA on the AC's certificate path MUST be directly trusted to 1491 issue PKCs which precede the AC issuer in the certification path; 1492 call this CA the "AA CA". 1494 2. All PKCs on the path from the AA CA, down to and including the AC 1495 issuer's PKC, MUST contain an AAControls extension; however, the 1496 PKC of the AA CA need not contain this extension. 1498 3. Only those attributes in the AC which are allowed, according to 1499 all of the AAControls extension values in all of the PKCs from the 1500 AA CA to the AC issuer, may be used for authorization decisions; 1501 all other attributes MUST be ignored. This check MUST be applied 1502 to the list of attributes following attribute decryption, and the 1503 id-aca-encAttrs type MUST also be checked. 1505 name id-pe-aaControls 1506 OID { id-pe 6 } 1507 syntax AAControls 1508 criticality MAY be TRUE 1510 8. Security Considerations 1512 The protection afforded for private keys is a critical factor in 1513 maintaining security. Failure of AC issuers to protect their private 1514 keys will permit an attacker to masquerade as them, potentially 1515 generating false ACs or revocation status. Existence of bogus ACs 1516 and revocation status will undermine confidence in the system. If 1517 the compromise is detected, all ACs issued by the AC issuer MUST be 1518 revoked. Rebuilding after such a compromise will be problematic, so 1519 AC issuers are advised to implement a combination of strong technical 1520 measures (e.g., tamper-resistant cryptographic modules) and 1521 appropriate management procedures (e.g., separation of duties) to 1522 avoid such an incident. 1524 Loss of an AC issuer's private signing key may also be problematic. 1525 The AC issuer would not be able to produce revocation status or 1526 perform AC renewal. AC issuers are advised to maintain secure backup 1527 for signing keys. The security of the key backup procedures is a 1528 critical factor in avoiding key compromise. 1530 The availability and freshness of revocation status will affect the 1531 degree of assurance that should be placed in a long-lived AC. While 1532 long-lived ACs expire naturally, events may occur during its natural 1533 lifetime which negate the binding between the AC holder and the 1534 attributes. If revocation status is untimely or unavailable, the 1535 assurance associated with the binding is clearly reduced. 1537 The binding between an AC holder and attributes cannot be stronger 1538 than the cryptographic module implementation and algorithms used to 1539 generate the signature. Short key lengths or weak hash algorithms 1540 will limit the utility of an AC. AC issuers are encouraged to note 1541 advances in cryptology so they can employ strong cryptographic 1542 techniques. 1544 Inconsistent application of name comparison rules may result in 1545 acceptance of invalid targeted or proxied ACs, or rejection of valid 1546 ones. The X.500 series of specifications defines rules for comparing 1547 distinguished names. These rules require comparison of strings 1548 without regard to case, character set, multi-character white space 1549 substrings, or leading and trailing white space. This specification 1550 and [PKIXPROF] relaxes these requirements, requiring support for 1551 binary comparison at a minimum. 1553 AC issuers MUST encode the distinguished name in the AC 1554 holder.entityName field identically to the distinguished name in the 1555 holder's PKC. If different encodings are used, implementations of 1556 this specification may fail to recognize that the AC and PKC belong 1557 to the same entity. 1559 If an attribute certificate is tied to the holder's PKC using the 1560 baseCertificateID component of the Holder field and the PKI in use 1561 includes a rogue CA with the same issuer name specified in the 1562 baseCertificateID component, this rogue CA could issue a PKC to a 1563 malicious party, using the same issuer name and serial number as the 1564 proper holder's PKC. Then the malicious party could use this PKC in 1565 conjunction with the AC. This scenario SHOULD be avoided by properly 1566 managing and configuring the PKI so that there cannot be two CAs with 1567 the same name. Another alternative is to tie ACs to PKCs using the 1568 publicKeyCert type in the ObjectDigestInfo field. Failing this, AC 1569 verifiers have to establish (using other means) that the potential 1570 collisions cannot actually occur, for example, the Certificte 1571 Practice Statements (CPSs) of the CAs involved may make it clear that 1572 no such name collisions can occur. 1574 Implementers MUST ensure that following validation of an AC, only 1575 attributes that the issuer is trusted to issue are used in 1576 authorization decisions. Other attributes, which MAY be present MUST 1577 be ignored. Given that the AAControls PKC extension is optional to 1578 implement, AC verifiers MUST be provided with this information by 1579 other means. Configuration information is a likely alternative 1580 means. This becomes very important if an AC verifier trusts more 1581 than one AC issuer. 1583 There is often a requirement to map between the authentication 1584 supplied by a particular security protocol (e.g. TLS, S/MIME) and the 1585 AC holder's identity. If the authentication uses PKCs, then this 1586 mapping is straightforward. However, it is envisaged that ACs will 1587 also be used in environments where the holder may be authenticated 1588 using other means. Implementers SHOULD be very careful in mapping 1589 the authenticated identity to the AC holder. 1591 9. IANA Considerations 1593 Attributes and attribute certificate extensions are identified by 1594 object identifiers (OIDs). Many of the OIDs used in this document 1595 are copied from X.509 [X.509-2000]. Other OIDs were assigned from an 1596 arc delegated by the IANA to the PKIX working group. No further 1597 action by the IANA is necessary for this document or any anticipated 1598 updates. 1600 10. References 1602 10.1. Normative References 1604 [CMS] Housley, R., "Cryptographic Message Syntax", RFC 3852, 1605 July 2004. 1607 [HTTP-URL] Housley, R., and P. Hoffman, "Internet X.509 Public 1608 Key Infrastructure Operational Protocols: FTP and 1609 HTTP", RFC 2585, May 1999. 1611 [LDAP-URL] Smith, E., and T. Howes, "Lightweight Directory Access 1612 Protocol (LDAP): Uniform Resource Locator", RFC 4516, 1613 June 2006. 1615 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1616 Requirement Levels", BCP 14, RFC 2119, March 1997. 1618 [RFC3281] Farrell, S., and R. Housley, "An Internet Attribute 1619 Certificate Profile for Authorization", RFC 3281, 1620 April 2002. 1622 [RFC3281-ERR] http://www.rfc-editor.org/errata_search.php?eid=302 1624 [PKIXALGS] Bassham, L., Polk, W. and R. Housley, "Algorithms and 1625 Identifiers for the Internet X.509 Public Key 1626 Infrastructure Certificate and Certificate Revocation 1627 Lists CRL Profile", RFC 3279, April 2002. 1629 Turner, S., Polk, W., Hously, R., Yiu, K., D. Brown, 1630 "Elliptic Curve Cryptography Subject Public Key 1631 Information", RFC 5480, February 2009. 1633 Schaad, J., Kaliski, B., and R. Housley, "Additional 1634 Algorithms and Identifiers for RSA Cryptography for 1635 use in the Internet X.509 Public Key Infrastructure 1636 Certificate and Certificate Revocation List (CRL) 1637 Profile", RFC 4055, June 2005. 1639 Turner, S., Polk, W., Hously, R., Yiu, K., D. Brown, 1640 "Update for RSAES-OAEP Algorithm Parameters", draft- 1641 ietf-pkix-rfc4055-update-01.txt, work-in-progress. 1643 [PKIXPROF] Cooper, D., Santesson, S., Farrell, S., Boeyen, S. 1644 Housley, R., and W. Polk, "Internet X.509 Public Key 1645 Infrastructure Certificate and Certificate Revocation 1646 List (CRL) Profile", RFC 5280, May 2008. 1648 [X.680] ITU-T Recommendation X.680 (2002) | ISO/IEC 8824- 1649 1:2002, Information technology - Abstract Syntax 1650 Notation One (ASN.1): Specification of basic 1651 notation. 1653 [X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825- 1654 1:2002, Information technology - ASN.1 encoding rules: 1655 Specification of Basic Encoding Rules (BER), Canonical 1656 Encoding Rules (CER) and Distinguished Encoding Rules 1657 (DER). 1659 10.2. Informative References 1661 [KRB] Yu, T., Hartman, S., Raeburn, K., and C. Neuman, "The 1662 Kerberos Network Authentication Service (V5)", RFC 1663 4120, July 2005. 1665 [LDAP] Zeilenga, K., "Lightweight Directory Access Protocol 1666 (LDAP): Directory Information Models", RFC 4510, June 1667 2006. 1669 [OCSP] Myers, M., Ankney, R., Malpani A., Galperin, S., and 1670 C. Adams, "X.509 Internet Public Key Infrastructure 1671 Online Certificate Status Protocol - OCSP", RFC 2560, 1672 June 1999. 1674 [X.509-1988] CCITT Recommendation X.509: The Directory - 1675 Authentication Framework. 1988. 1677 [X.509-1997] ITU-T Recommendation X.509: The Directory - 1678 Authentication Framework. 1997. 1680 [X.509-2000] ITU-T Recommendation X.509: The Directory - Public-Key 1681 and Attribute Certificate Frameworks. 2000 1683 Appendix A Object Identifiers 1685 This (normative) appendix lists the new object identifiers which are 1686 defined in this specification. Some of these are required only for 1687 support of optional features and are not required for conformance to 1688 this profile. This specification mandates support for OIDs which 1689 have arc elements with values that are less than 2^32, (i.e. they 1690 MUST be between 0 and 4,294,967,295 inclusive) and SHOULD be less 1691 than 2^31 (i.e. less than or equal to 2,147,483,647). This allows 1692 each arc element to be represented within a single 32 bit word. 1693 Implementations MUST also support OIDs where the length of the dotted 1694 decimal (see [LDAP], section 4.1.2) string representation can be up 1695 to 100 bytes (inclusive). Implementations MUST be able to handle 1696 OIDs with up to 20 elements (inclusive). AA's SHOULD NOT issue ACs 1697 which contain OIDs that breach these requirements. 1699 The following OIDs are imported from [PKIXPROF]: 1701 id-pkix OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) 1702 dod(6) internet(1) security(5) mechanisms(5) pkix(7) } 1703 id-mod OBJECT IDENTIFIER ::= { id-pkix 0 } 1704 id-pe OBJECT IDENTIFIER ::= { id-pkix 1 } 1705 id-ad OBJECT IDENTIFIER ::= { id-pkix 48 } 1706 id-at OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) ds(5) 4 } 1707 id-ce OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) ds(5) 29 } 1709 The following new ASN.1 module OID is defined: 1711 id-mod-attribute-cert OBJECT IDENTIFIER ::= { id-mod 12 } 1713 The following AC extension OIDs are defined: 1715 id-pe-ac-auditIdentity OBJECT IDENTIFIER ::= { id-pe 4 } 1716 id-pe-ac-proxying OBJECT IDENTIFIER ::= { id-pe 10 } 1717 id-ce-targetInformation OBJECT IDENTIFIER ::= { id-ce 55 } 1719 The following PKC extension OIDs are defined: 1721 id-pe-aaControls OBJECT IDENTIFIER ::= { id-pe 6 } 1723 The following attribute OIDs are defined: 1725 id-aca OBJECT IDENTIFIER ::= { id-pkix 10 } 1726 id-aca-authenticationInfo OBJECT IDENTIFIER ::= { id-aca 1 } 1727 id-aca-accessIdentity OBJECT IDENTIFIER ::= { id-aca 2 } 1728 id-aca-chargingIdentity OBJECT IDENTIFIER ::= { id-aca 3 } 1729 id-aca-group OBJECT IDENTIFIER ::= { id-aca 4 } 1730 id-aca-encAttrs OBJECT IDENTIFIER ::= { id-aca 6 } 1731 id-at-role OBJECT IDENTIFIER ::= { id-at 72 } 1732 id-at-clearance OBJECT IDENTIFIER ::= { 1733 joint-iso-ccitt(2) ds(5) attributeType(4) clearance (55) } 1734 id-at-clearance OBJECT IDENTIFIER ::= { 1735 joint-iso-ccitt(2) ds(5) module(1) selected-attribute-types(5) 1736 clearance (55) } 1738 As noted in Section 4.4.6, there are two OIDs for id-at-clearance. 1740 Appendix B ASN.1 Module 1742 This appendix describes data objects used by conforming PKI 1743 components in an "ASN.1-like" syntax. This syntax is a hybrid of the 1744 1988 and 1993 ASN.1 syntaxes. The 1988 ASN.1 syntax is augmented 1745 with 1993 UNIVERSAL Types UniversalString, BMPString, and UTF8String. 1747 The ASN.1 syntax does not permit the inclusion of type statements in 1748 the ASN.1 module, and the 1993 ASN.1 standard does not permit use of 1749 the new UNIVERSAL types in modules using the 1988 syntax. As a 1750 result, this module does not conform to either version of the ASN.1 1751 standard. 1753 This appendix may be converted into 1988 ASN.1 by replacing the 1754 definitions for the UNIVERSAL Types with the 1988 catch-all "ANY". 1756 NOTE: The value for TBA will be included during AUTH48. 1758 //** RFC Editor: Remove this note prior to publication **// 1760 PKIXAttributeCertificate-2008 { iso(1) identified-organization(3) 1761 dod(6) internet(1) security(5) mechanisms(5) pkix(7) id-mod(0) 1762 id-mod-attribute-cert2(TBA) } 1764 DEFINITIONS IMPLICIT TAGS ::= 1766 BEGIN 1768 -- EXPORTS ALL -- 1770 IMPORTS 1771 -- IMPORTed module OIDs MAY change if [PKIXPROF] changes 1772 -- PKIX Certificate Extensions 1774 Attribute, AlgorithmIdentifier, CertificateSerialNumber, 1775 Extensions, UniqueIdentifier, id-pkix, id-pe, id-kp, id-ad, id-at 1776 FROM PKIX1Explicit88 1777 { iso(1) identified-organization(3) dod(6) internet(1) 1778 security(5) mechanisms(5) pkix(7) id-mod(0) 1779 id-pkix1-explicit-88(18) } 1781 GeneralName, GeneralNames, id-ce, AuthorityKeyIdentifier, 1782 AuthorityInfoAccessSyntax, CRLDistributionPoint 1783 FROM PKIX1Implicit88 1784 { iso(1) identified-organization(3) dod(6) internet(1) 1785 security(5) mechanisms(5) pkix(7) id-mod(0) 1786 id-pkix1-implicit-88(19) } 1788 ContentInfo 1789 FROM CryptographicMessageSyntax2004 1790 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) 1791 smime(16) modules(0) cms-2004(24) } 1793 ; 1795 id-pe-ac-auditIdentity OBJECT IDENTIFIER ::= { id-pe 4 } 1797 id-pe-aaControls OBJECT IDENTIFIER ::= { id-pe 6 } 1799 id-pe-ac-proxying OBJECT IDENTIFIER ::= { id-pe 10 } 1801 id-ce-targetInformation OBJECT IDENTIFIER ::= { id-ce 55 } 1803 id-aca OBJECT IDENTIFIER ::= { id-pkix 10 } 1805 id-aca-authenticationInfo OBJECT IDENTIFIER ::= { id-aca 1 } 1807 id-aca-accessIdentity OBJECT IDENTIFIER ::= { id-aca 2 } 1809 id-aca-chargingIdentity OBJECT IDENTIFIER ::= { id-aca 3 } 1811 id-aca-group OBJECT IDENTIFIER ::= { id-aca 4 } 1813 -- { id-aca 5 } is reserved 1815 id-aca-encAttrs OBJECT IDENTIFIER ::= { id-aca 6 } 1817 id-at-role OBJECT IDENTIFIER ::= { id-at 72} 1818 id-at-clearance OBJECT IDENTIFIER ::= { 1819 joint-iso-ccitt(2) ds(5) attributeType(4) clearance (55) } 1821 -- Uncomment the following declaration and comment the above line if 1822 -- using the id-at-clearance attribute as defined in [RFC3281] 1824 -- id-at-clearance OBJECT IDENTIFIER ::= { 1825 -- joint-iso-ccitt(2) ds(5) module(1) selected-attribute-types(5) 1826 -- clearance (55) } 1828 -- Uncomment this if using a 1988 level ASN.1 compiler 1830 -- UTF8String ::= [UNIVERSAL 12] IMPLICIT OCTET STRING 1832 AttributeCertificate ::= SEQUENCE { 1833 acinfo AttributeCertificateInfo, 1834 signatureAlgorithm AlgorithmIdentifier, 1835 signatureValue BIT STRING 1836 } 1838 AttributeCertificateInfo ::= SEQUENCE { 1839 version AttCertVersion, -- version is v2 1840 holder Holder, 1841 issuer AttCertIssuer, 1842 signature AlgorithmIdentifier, 1843 serialNumber CertificateSerialNumber, 1844 attrCertValidityPeriod AttCertValidityPeriod, 1845 attributes SEQUENCE OF Attribute, 1846 issuerUniqueID UniqueIdentifier OPTIONAL, 1847 extensions Extensions OPTIONAL 1848 } 1850 AttCertVersion ::= INTEGER { v2(1) } 1852 Holder ::= SEQUENCE { 1853 baseCertificateID [0] IssuerSerial OPTIONAL, 1854 -- the issuer and serial number of 1855 -- the holder's Public Key Certificate 1856 entityName [1] GeneralNames OPTIONAL, 1857 -- the name of the claimant or role 1858 objectDigestInfo [2] ObjectDigestInfo OPTIONAL 1859 -- used to directly authenticate the 1860 -- holder, for example, an executable 1861 } 1862 ObjectDigestInfo ::= SEQUENCE { 1863 digestedObjectType ENUMERATED { 1864 publicKey (0), 1865 publicKeyCert (1), 1866 otherObjectTypes (2) }, 1867 -- otherObjectTypes MUST NOT 1868 -- MUST NOT be used in this profile 1869 otherObjectTypeID OBJECT IDENTIFIER OPTIONAL, 1870 digestAlgorithm AlgorithmIdentifier, 1871 objectDigest BIT STRING 1872 } 1874 AttCertIssuer ::= CHOICE { 1875 v1Form GeneralNames, -- MUST NOT be used in this 1876 -- profile 1877 v2Form [0] V2Form -- v2 only 1878 } 1880 V2Form ::= SEQUENCE { 1881 issuerName GeneralNames OPTIONAL, 1882 baseCertificateID [0] IssuerSerial OPTIONAL, 1883 objectDigestInfo [1] ObjectDigestInfo OPTIONAL 1884 -- issuerName MUST be present in this profile 1885 -- baseCertificateID and objectDigestInfo MUST 1886 -- NOT be present in this profile 1887 } 1889 IssuerSerial ::= SEQUENCE { 1890 issuer GeneralNames, 1891 serial CertificateSerialNumber, 1892 issuerUID UniqueIdentifier OPTIONAL 1893 } 1895 AttCertValidityPeriod ::= SEQUENCE { 1896 notBeforeTime GeneralizedTime, 1897 notAfterTime GeneralizedTime 1898 } 1900 Targets ::= SEQUENCE OF Target 1902 Target ::= CHOICE { 1903 targetName [0] GeneralName, 1904 targetGroup [1] GeneralName, 1905 targetCert [2] TargetCert 1906 } 1907 TargetCert ::= SEQUENCE { 1908 targetCertificate IssuerSerial, 1909 targetName GeneralName OPTIONAL, 1910 certDigestInfo ObjectDigestInfo OPTIONAL 1911 } 1913 IetfAttrSyntax ::= SEQUENCE { 1914 policyAuthority [0] GeneralNames OPTIONAL, 1915 values SEQUENCE OF CHOICE { 1916 octets OCTET STRING, 1917 oid OBJECT IDENTIFIER, 1918 string UTF8String 1919 } 1920 } 1922 SvceAuthInfo ::= SEQUENCE { 1923 service GeneralName, 1924 ident GeneralName, 1925 authInfo OCTET STRING OPTIONAL 1926 } 1928 RoleSyntax ::= SEQUENCE { 1929 roleAuthority [0] GeneralNames OPTIONAL, 1930 roleName [1] GeneralName 1931 } 1933 Clearance ::= SEQUENCE { 1934 policyId OBJECT IDENTIFIER, 1935 classList ClassList DEFAULT {unclassified}, 1936 securityCategories SET OF SecurityCategory OPTIONAL 1937 } 1939 -- Uncomment the following lines to support deprecated clearance 1940 -- syntax and comment out previous Clearance. 1942 -- Clearance ::= SEQUENCE { 1943 -- policyId [0] OBJECT IDENTIFIER, 1944 -- classList [1] ClassList DEFAULT {unclassified}, 1945 -- securityCategories [2] SET OF SecurityCategory OPTIONAL 1946 -- } 1947 ClassList ::= BIT STRING { 1948 unmarked (0), 1949 unclassified (1), 1950 restricted (2), 1951 confidential (3), 1952 secret (4), 1953 topSecret (5) 1954 } 1956 SecurityCategory ::= SEQUENCE { 1957 type [0] OBJECT IDENTIFIER, 1958 value [1] EXPLICIT ANY DEFINED BY type 1959 } 1961 -- Note that in [RFC3281] the syntax for SecurityCategory was 1962 -- as follows: 1963 -- 1964 -- SecurityCategory ::= SEQUENCE { 1965 -- type [0] IMPLICIT OBJECT IDENTIFIER, 1966 -- value [1] ANY DEFINED BY type 1967 -- } 1968 -- 1969 -- The removal of the IMPLICIT from the type line and the 1970 -- addition of the EXPLICIT to the value line result in 1971 -- no changes to the encoding. 1973 AAControls ::= SEQUENCE { 1974 pathLenConstraint INTEGER (0..MAX) OPTIONAL, 1975 permittedAttrs [0] AttrSpec OPTIONAL, 1976 excludedAttrs [1] AttrSpec OPTIONAL, 1977 permitUnSpecified BOOLEAN DEFAULT TRUE 1978 } 1980 AttrSpec ::= SEQUENCE OF OBJECT IDENTIFIER 1982 ACClearAttrs ::= SEQUENCE { 1983 acIssuer GeneralName, 1984 acSerial INTEGER, 1985 attrs SEQUENCE OF Attribute 1986 } 1988 ProxyInfo ::= SEQUENCE OF Targets 1990 END 1992 Appendix C Changes Since RFC 3281 1994 1. Created a new Section 1.1 "Terminology", renumbered Section 1.1- 1995 1.3 to 1.2-1.4, and moved first paragraph of Section 1 to Section 1996 1.1. 1998 2. In Section 2, replace S/MIME v3 with S/MIME v3.2. 2000 3. In Section 4.1, moved "," from the right of the ASN.1 comment to 2001 the left of the ASN.1 comment on the line describing version in the 2002 AttributerCertificateInfo structure. Replaced reference to X.208 with 2003 X.690. 2005 4. In Section 4.2, replaced pointer to 4.2.1.7 of RFC 3280 with 2006 pointer to 4.2.1.6 of RFC 5280. 2008 5. In Section 4.3.2, replaced "Confirming" with "Conforming". 2010 6. In Section 4.3.4, replaced reference to RFC 1738, URL, with 2011 references to [HTTP-URL]. 2013 7. In Section 4.3.5, replaced "HTTP or an LDAP" with "HTTP [HTTP-URL] 2014 or an LDAP [LDAP-URL]". Also replaced "CRLDistPointsSyntax" with 2015 "CRLDistributionPoints". 2017 8. In Section 4.4.6, added text to address having two OIDs for the 2018 same syntax and two syntaxes for one OID. 2020 9. In Section 7.1, replaced text that described encapsulating 2021 encrypted attribute with corrected text. Reworded last paragraph to 2022 more clearly describe the failure case. 2024 10. Updated References: 2025 a) split references in to informative/normative references 2026 b) added reference to RFC 3281 2027 c) replaced reference to X.501:1993 with X.501:1997 2028 d) replaced reference to RFC 1510 with RFC 4120 2029 e) replaced reference to RFC 1738 with RFC 4516 and 2585 2030 f) replaced reference to RFC 2251 with RFC 4510 2031 g) replaced reference to RFC 2459 with RFC 5280 2032 h) replaced reference to RFC 2510 with RFC 4210 2033 i) replaced reference to RFC 2630 with RFC 3852 2034 j) replaced reference to RFC 2797 with RFC 5272 2035 k) replaced reference to X.208-1988 with X.690 2036 l) added reference to X.680 2037 m) expanded reference to RFC 3279 by adding RFC 5480 and RFC 4055, 2038 which update RFC 3279 2040 n) deleted spurious reference to CMC, CMP, ESS, RFC 2026, 2041 X.209-88, and X.501:1988. 2043 11. In Appendix A, added 2nd clearance attribute object identifier. 2045 12. Appendix B, updated ASN.1 with changes 3, 8, 9, and 11: 2046 a) New OID for ASN.1 module. 2047 b) Updated module OIDs for PKIX1Explicit88 and PKIX1Implicit88. 2048 c) Added imports from PKIX1Implicit88 for AuthorityKeyIdentifier, 2049 AuthorityInfoAccessSyntax, CRLDistributionPoint 2050 d) Added imports from CryptographicMessageSyntax2004 for 2051 ContentInfo. 2052 e) Added comments and commented out ASN.1 for old clearance 2053 attribute syntax. 2054 f) Added preamble to ASN.1, which is taken from Appendix A of 2055 RFC5280. 2057 Author's Addresses 2059 Sean Turner 2061 IECA, Inc. 2062 3057 Nutley Street, Suite 106 2063 Fairfax, VA 22031 2064 USA 2066 Email: turners@ieca.com 2068 Russ Housley 2070 Vigil Security, LLC 2071 918 Spring Knoll Drive 2072 Herndon, VA 20170 2073 USA 2075 EMail: housley@vigilsec.com 2077 Stephen Farrell 2079 Distributed Systems Group 2080 Computer Science Department 2081 Trinity College Dublin 2082 Ireland 2084 Email: stephen.farrell@cs.tcd.ie