idnits 2.17.1 draft-young-entity-category-07.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (January 31, 2018) is 2275 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 4844 (Obsoleted by RFC 8729) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group I. Young, Ed. 3 Internet-Draft Independent 4 Intended status: Informational L. Johansson 5 Expires: August 4, 2018 SUNET 6 S. Cantor 7 Shibboleth Consortium 8 January 31, 2018 10 The Entity Category SAML Attribute Types 11 draft-young-entity-category-07 13 Abstract 15 This document describes a SAML entity attribute which can be used to 16 assign category membership semantics to an entity, and a second 17 attribute for use in claiming interoperation with or support for 18 entities in such categories. 20 This document is a product of the Research and Education Federations 21 (REFEDS) Working Group process. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at https://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on August 4, 2018. 40 Copyright Notice 42 Copyright (c) 2018 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (https://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 1.1. REFEDS Document Process . . . . . . . . . . . . . . . . . 3 56 2. Notation and Conventions . . . . . . . . . . . . . . . . . . 3 57 3. Entity Category Attribute . . . . . . . . . . . . . . . . . . 4 58 3.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 3.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 4 60 3.3. Entity Category Example . . . . . . . . . . . . . . . . . 6 61 4. Entity Category Support Attribute . . . . . . . . . . . . . . 6 62 4.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 6 63 4.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 7 64 4.3. Entity Category Support Example . . . . . . . . . . . . . 8 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 67 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 68 7.1. Normative References . . . . . . . . . . . . . . . . . . 10 69 7.2. Informative References . . . . . . . . . . . . . . . . . 10 70 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11 71 Appendix B. Change Log (to be removed by RFC Editor before 72 publication) . . . . . . . . . . . . . . . . . . . . 11 73 B.1. Since draft-young-entity-category-05 . . . . . . . . . . 11 74 B.2. Since draft-young-entity-category-04 . . . . . . . . . . 11 75 B.3. Since draft-young-entity-category-03 . . . . . . . . . . 11 76 B.4. Since draft-young-entity-category-02 . . . . . . . . . . 11 77 B.5. Since draft-young-entity-category-01 . . . . . . . . . . 12 78 B.6. Since draft-young-entity-category-00 . . . . . . . . . . 12 79 B.7. Since draft-macedir-entity-category . . . . . . . . . . . 13 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 82 1. Introduction 84 This document describes a SAML attribute, referred to here as the 85 "entity category attribute", values of which represent entity types 86 or categories. When used with the SAML V2.0 Metadata Extension for 87 Entity Attributes [SAML2MetadataAttr] each such entity category 88 attribute value represents a claim that the entity thus labelled 89 meets the requirements of, and is asserted to be a member of, the 90 indicated category. 92 These category membership claims MAY be used by a relying party to 93 provision policy for release of attributes from an identity provider, 94 to influence user interface decisions such as those related to 95 identity provider discovery, or for any other purpose. In general, 96 the intended uses of any claim of membership in a given category will 97 depend on the details of the category's definition, and will often be 98 included as part of that definition. 100 Entity category attribute values are URIs, and this document 101 therefore does not specify a controlled vocabulary for assigning 102 entity category values. Category URIs may be defined by any 103 appropriate authority without any requirement for central 104 registration. It is anticipated that other specifications may 105 provide management and discovery mechanisms for entity category 106 attribute values. 108 A second SAML attribute, referred to here as the "entity category 109 support attribute", contains URI values which represent claims that 110 an entity supports and/or interoperates with entities in a given 111 category or categories. These values, defined in conjunction with 112 specific entity category values, provide entities in a category with 113 the means to identify peer entities that wish to interact with them 114 in a fashion described by the category specification. 116 This document does not specify any values either for the entity 117 category attribute or for the entity category support attribute. 119 1.1. REFEDS Document Process 121 The Research and Education Federations group ([REFEDS]) is the voice 122 that articulates the mutual needs of research and education identity 123 federations worldwide. It aims to represent the requirements of 124 research and education in the ever-growing space of access and 125 identity management. 127 From time to time REFEDS will wish to publish a document in the 128 Internet RFC series. Such documents will be published as part of the 129 RFC Independent Submission Stream [RFC4844]; however the REFEDS 130 working group sign-off process will have been followed for these 131 documents, as described in the REFEDS Participant's Agreement 132 [REFEDS.agreement]. 134 This document is a product of the REFEDS Working Group process. 136 2. Notation and Conventions 138 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 139 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 140 document are to be interpreted as described in RFC 2119 [BCP14]. 142 3. Entity Category Attribute 144 3.1. Syntax 146 Entity category attribute values MUST be valid URIs. It is 147 RECOMMENDED that http:-scheme or https:-scheme URIs are used, and 148 further RECOMMENDED that an entity category URI resolves to a human- 149 readable document defining the category. 151 Authorities defining entity categories MUST produce a specification 152 of the entity category and SHOULD make arrangement for the entity 153 category URI to resolve to the specification in human readable form. 155 Authorities defining entity categories MAY use versioning of entity 156 category URIs where appropriate, in which case each version of the 157 specification of the entity category SHOULD clearly indicate the 158 latest version of the entity category URI (and hence of the 159 specification). The specification SHOULD include a description of 160 how the authority defining the entity category implements governance 161 for the specification in the case when the specification may be 162 updated. 164 When used in SAML metadata or protocol elements, the entity category 165 attribute MUST be encoded as a SAML 2.0 Attribute element with 166 @NameFormat urn:oasis:names:tc:SAML:2.0:attrname-format:uri and @Name 167 http://macedir.org/entity-category. 169 A SAML entity is associated with one or more categories by including 170 the Attribute element described here in the entity's metadata through 171 use of the [SAML2MetadataAttr] metadata extension, in which the 172 Attribute element is contained within an mdattr:EntityAttributes 173 element directly contained within an md:Extensions element directly 174 contained within the entity's md:EntityDescriptor. 176 The meaning of the entity category attribute is undefined by this 177 specification if it appears anywhere else within a metadata instance, 178 or within any other XML document. 180 If the entity category attribute Attribute element appears more than 181 once in the metadata for an entity, the combined set of associated 182 attribute values SHOULD be interpreted by relying parties as if they 183 all appeared within a single Attribute element. 185 3.2. Semantics 187 The presence of the entity category attribute within an entity's 188 entity attributes represents a series of claims (one for each 189 attribute value) that the entity is a member of each named category. 191 The precise semantics of such a claim depend on the definition of the 192 category itself. 194 An entity may be claimed to be a member of more than one category. 195 In this case, the entity is claimed to meet the requirements of each 196 category independently unless otherwise specified by the category 197 definitions themselves. 199 The definition of the concept of a category is intentionally not 200 addressed in this document, in order to leave it as general as 201 possible. However, to be useful, category definitions SHOULD include 202 the following as appropriate: 204 o A definition of the authorities who may validly assert membership 205 in the category. While membership in some categories may be self- 206 asserted informally by an entity's owner, others may need to be 207 validated by third parties such as the entity's home federation or 208 other registrar. 210 o A set of criteria by which an entity's membership in the category 211 can be objectively assessed. 213 o A definition of the processes by which valid authorities may 214 determine that an entity meets the category's membership criteria. 216 o A description of the anticipated uses for category membership by 217 relying parties. 219 o A statement indicating the applicability or otherwise of 220 membership of the entity category to different SAML role 221 descriptors, and any protocol support restrictions that may be 222 relevant. 224 Entity categories SHOULD NOT be used to indicate the certification 225 status of an entity regarding its conformance to the requirements of 226 an identity assurance framework. The [SAML2IDAssuranceProfile] 227 extension SHOULD be used for this purpose. 229 If significant changes are made to a category definition, the new 230 version of the category SHOULD be represented by a different category 231 URI so that the old and new versions can be distinguished by a 232 relying party. It is for this reason that authorities defining 233 entity categories MAY employ some form of versioning for entity 234 category URI. When versioning is used each version of the entity 235 category MUST be treated as a separate URI. 237 No ordering relation is defined over entity category value URIs. 238 Entity category attribute value URIs MUST be treated as opaque 239 strings for the purpose of comparison. In particular, if the 240 specification defining the entity category relies on versioning of 241 the entity category URI, a relying party MUST NOT assume any 242 particular ordering between different versions of the entity 243 category. Any order between versions MUST be spelled out in the 244 specification. 246 3.3. Entity Category Example 248 250 251 253 256 http://example.org/category/dog 258 urn:oid:1.3.6.1.4.1.21829 259 260 261 262 ... 263 265 4. Entity Category Support Attribute 267 4.1. Syntax 269 Entity category support attribute values MUST be URIs. It is 270 RECOMMENDED that http:-scheme or https:-scheme URLs are used, and 271 further RECOMMENDED that each such value resolves to a human-readable 272 document defining the value's semantics. A given entity category 273 value MAY be associated with multiple support values in order to 274 allow for multiple forms of support, participation, or interoperation 275 with entities in the category. The authoritiy defining the entity 276 category and entity category support values MUST clearly describe the 277 relationship between (all versions of) the entity category URI and 278 (all versions of) the entity category support URIs as applicable in 279 the entity category specification. 281 The entity category support attribute MUST be encoded as a SAML 2.0 282 Attribute element with @NameFormat 283 urn:oasis:names:tc:SAML:2.0:attrname-format:uri and @Name 284 http://macedir.org/entity-category-support. 286 Claims that a SAML entity implements support for one or more 287 categories are represented by including the Attribute element 288 described here in the entity's metadata through use of the 289 [SAML2MetadataAttr] metadata extension, in which the Attribute 290 element is contained within an mdattr:EntityAttributes element 291 directly contained within an md:Extensions element directly contained 292 within the entity's md:EntityDescriptor. 294 The meaning of the entity category support attribute is undefined by 295 this specification if it appears anywhere else within a metadata 296 instance, or within any other XML document. 298 If the entity category support attribute Attribute element appears 299 more than once in the metadata for an entity, the combined set of 300 associated attribute values SHOULD be interpreted by relying parties 301 as if they all appeared within a single Attribute element. 303 4.2. Semantics 305 The presence of the entity category support attribute within an 306 entity's entity attributes represents a series of claims (one for 307 each attribute value) that the entity supports peer entities in a 308 category in a particular fashion. The precise semantics of such a 309 claim depend on the definition of the category support identifier 310 itself. Category support claims will often be defined to be self- 311 asserted. 313 An entity may be claimed to support more than one category. In this 314 case, the entity is claimed to meet the support requirements of each 315 category independently unless otherwise specified by the category 316 definitions themselves. 318 The definition of the concept of "support" for a category is 319 intentionally not addressed in this document, in order to leave it as 320 general as possible. It is assumed that entity category definitions 321 MAY define one or more support values signifying particular 322 definitions for "support" by peers as motivated by use cases arising 323 from the definition of the category itself. 325 A common case is expected to be the definition of a single support 326 value whose URI is identical to that defined for the category itself. 328 If significant changes are made to a category support definition, the 329 new version SHOULD be represented by a different category support URI 330 so that the old and new versions can be distinguished by a relying 331 party. It is for this reason that authorities defining entity 332 categories support MAY employ some form of versioning. When 333 versioning is used each version of the entity category support URI 334 MUST be treated as a separate URI. 336 No ordering relation is defined over entity category URIs. Entity 337 category attribute support value URIs MUST be treated as opaque 338 strings for the purpose of comparison. In particular, if the 339 specification defining the entity category support values relies on 340 versioning, a relying party MUST NOT assume any particular ordering 341 between different versions of the entity category support URI. Any 342 order between versions MUST be spelled out in the specification. 344 4.3. Entity Category Support Example 346 348 349 351 354 http://example.org/category/dog/basic 356 http://example.org/category/dog/advanced 358 urn:oid:1.3.6.1.4.1.21829 359 360 361 362 ... 363 365 5. IANA Considerations 367 This memo includes no request to IANA. 369 6. Security Considerations 371 The presence of the entity category attribute within an entity's 372 entity attributes represents a series of claims (one for each 373 attribute value) that the entity is a member of the named categories. 374 Before accepting and acting on such claims, any relying party needs 375 to establish, at a level of assurance sufficient for the intended 376 use, a chain of trust concluding that the claim is justified. 378 Some of the elements in such a chain of trust might include: 380 o The integrity of the metadata delivered to the relying party, as 381 for example assured by a digital signature. 383 o If the entity category attribute is carried within a signed 384 assertion, the assertion itself must be evaluated. 386 o The policies and procedures of the immediate source of the 387 metadata; in particular, any procedures the immediate source has 388 with regard to aggregation of metadata from other sources. 390 o The policies and procedures implemented by agents along the 391 publication path from the original metadata registrar: this may be 392 determined either by examination of the published procedures of 393 each agent in turn, or may be simplified if the entity metadata 394 includes publication path metadata in mdrpi:PublicationPath 395 elements as described in [SAML2MetadataRPI] section 2.3.1. 397 o The policies and procedures implemented by the original metadata 398 registrar. The registrar's identity may be known implicitly, or 399 may be determined from the entity metadata if it includes an 400 mdrpi:RegistrationInfo element and corresponding 401 @registrationAuthority attribute as described in 402 [SAML2MetadataRPI] section 2.1.1. 404 o The definition of the category itself; in particular, any 405 statements it makes about whether membership of the category may 406 be self-asserted, or may only be asserted by particular 407 authorities. 409 Although entity category support attribute values will often be 410 defined as self-asserted claims by the containing entity, the 411 provenance of the metadata remains relevant to a relying party's 412 decision to accept a claim of support as legitimate, and the specific 413 definition of a support claim will influence the assurance required 414 to act on it. 416 The conclusion that a claim of category membership or support is 417 justified and should be acted upon may require a determination of the 418 origin of the claim. This may not be necessary if the immediate 419 source of the metadata is trusted to such an extent that the trust 420 calculation is essentially delegated to it. 422 In many cases, a claim will be included in an entity's metadata by 423 the original metadata registrar on behalf of the entity's owner, and 424 the mdrpi:RegistrationInfo element's @registrationAuthority attribute 425 is available to carry the registrar's identity. However, any agent 426 that is part of the chain of custody between the original registrar 427 and the final relying party may have added, removed or transformed 428 claims according to local policy. For example, an agent charged with 429 redistributing metadata may remove claims it regards as 430 untrustworthy, or add others which were not already present if they 431 have value to its intended audience. 433 7. References 435 7.1. Normative References 437 [BCP14] Bradner, S., "Key words for use in RFCs to Indicate 438 Requirement Levels", BCP 14, RFC 2119, March 1997. 440 [SAML2MetadataAttr] 441 Cantor, S., Ed., "SAML V2.0 Metadata Extension for Entity 442 Attributes", August 2009, 443 . 445 [SAML2MetadataRPI] 446 La Joie, C., Ed., "SAML V2.0 Metadata Extensions for 447 Registration and Publication Information Version 1.0", 448 April 2012, 449 . 451 7.2. Informative References 453 [REFEDS] Research and Education Federations, "REFEDS Home Page", 454 . 456 [REFEDS.agreement] 457 Research and Education Federations, "REFEDS Participant's 458 Agreement", 459 . 461 [RFC4844] Daigle, L. and Internet Architecture Board, "The RFC 462 Series and RFC Editor", RFC 4844, July 2007. 464 [SAML2IDAssuranceProfile] 465 Morgan, RL., Ed., Madsen, P., Ed., and S. Cantor, Ed., 466 "SAML V2.0 Identity Assurance Profiles Version 1.0", 467 November 2010, . 470 Appendix A. Acknowledgements 472 This work has been a collaborative effort within the REFEDS and MACE- 473 Dir communities. Special thanks to (in no particular order): 475 o RL 'Bob' Morgan 477 o Ken Klingenstein 479 o Keith Hazelton 481 o Steven Olshansky 483 o Mikael Linden 485 o Nicole Harris 487 o Tom Scavo 489 Appendix B. Change Log (to be removed by RFC Editor before publication) 491 B.1. Since draft-young-entity-category-05 493 Recommendation on versioning and language on requirements for entity 494 category specification. 496 B.2. Since draft-young-entity-category-04 498 No substantive changes. 500 B.3. Since draft-young-entity-category-03 502 Additional improvements in response to IETF Gen-Art review: 504 o Section 3.2: additional SHOULD language recommending that category 505 definitions include applicability information for particular SAML 506 role descriptors. 508 o Section 3.2: added an informative reference to 509 [SAML2IDAssuranceProfile] and language recommending its use over 510 entity categories where appropriate. 512 B.4. Since draft-young-entity-category-02 514 Fix link to the REFEDS Participant's Agreement [REFEDS.agreement]. 516 Clarifications in response to IETF Gen-Art review: 518 o Section 1: make explicit the fact that we don't specify any values 519 of either attribute in this document. 521 o Section 3.1, Section 4.1: clarify that it is possible for 522 attribute values to appear within multiple Attribute elements, and 523 that this SHOULD be regarded as equivalent to combining them 524 within a single Attribute element. 526 o Section 3.2, Section 4.2: clarify the expectation that categories 527 are independent unless their definitions say otherwise. 529 o Section 3.2, Section 4.2: If significant changes are made to a 530 category definition, the new version of the category SHOULD be 531 represented by a different category URI *so that the old and new 532 versions can be distinguished by a relying party*. 534 o Section 3.2, Section 4.2: *No ordering relation is defined over 535 entity category value URIs.* Entity category attribute value URIs 536 MUST be treated as opaque strings *for the purpose of comparison*. 538 B.5. Since draft-young-entity-category-01 540 Changes from REFEDS consultation process: 542 1. Simplify title from "The Entity Category SAML Entity Metadata 543 Attribute Types" to "The Entity Category SAML Attribute Types". 545 2. Clarify the use of [SAML2MetadataRPI] in Section 6 by indicating 546 the elements and attributes to be used, and the sections of 547 [SAML2MetadataRPI] in which they are defined. 549 3. Remove any implication that category and category support claims 550 are necessarily being made "by" the entity itself. 552 4. Clarify that the origin of a category membership or support claim 553 may not always be the original registrar. 555 Grammar fix in Abstract. 557 Change the reference anchor for the SAML [SAML2MetadataRPI] 558 extension, as it now more commonly known as RPI than its original DRI 559 abbreviation. 561 B.6. Since draft-young-entity-category-00 563 Update affiliations for Leif Johansson and Scott Cantor. 565 Remove authors from acknowledgements. 567 Reorganize some of the introductory boilerplate sections. 569 B.7. Since draft-macedir-entity-category 571 Adopted as base for draft-young-entity-category-00. 573 Changed ipr from "pre5378Trust200902" to "trust200902" and submission 574 type from IETF to independent. 576 Designate Ian Young as editor for this version. Set more general 577 affiliation. 579 Modernised reference to RFC 2119 [BCP14] and moved that reference to 580 the introduction. 582 Adjusted layout of examples so that they don't exceed the RFC 583 standard line length. 585 Minor typographical nits but (intentionally) no substantive content 586 changes. 588 Authors' Addresses 590 Ian A. Young (editor) 591 Independent 593 EMail: ian@iay.org.uk 595 Leif Johansson 596 SUNET 598 EMail: leifj@sunet.se 600 Scott Cantor 601 Shibboleth Consortium 603 EMail: cantor.2@osu.edu