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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 5226 (Obsoleted by RFC 8126) ** Obsolete normative reference: RFC 7049 (Obsoleted by RFC 8949) ** Obsolete normative reference: RFC 8152 (Obsoleted by RFC 9052, RFC 9053) == Outdated reference: A later version (-46) exists of draft-ietf-ace-oauth-authz-12 -- Obsolete informational reference (is this intentional?): RFC 7159 (Obsoleted by RFC 8259) Summary: 4 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ACE M. Jones 3 Internet-Draft Microsoft 4 Intended status: Standards Track L. Seitz 5 Expires: December 31, 2018 RISE SICS 6 G. Selander 7 Ericsson AB 8 S. Erdtman 9 Spotify 10 H. Tschofenig 11 ARM Ltd. 12 June 29, 2018 14 Proof-of-Possession Key Semantics for CBOR Web Tokens (CWTs) 15 draft-ietf-ace-cwt-proof-of-possession-03 17 Abstract 19 This specification describes how to declare in a CBOR Web Token (CWT) 20 that the presenter of the CWT possesses a particular proof-of- 21 possession key. Being able to prove possession of a key is also 22 sometimes described as being the holder-of-key. This specification 23 provides equivalent functionality to "Proof-of-Possession Key 24 Semantics for JSON Web Tokens (JWTs)" (RFC 7800), but using CBOR and 25 CWTs rather than JSON and JWTs. 27 Status of This Memo 29 This Internet-Draft is submitted in full conformance with the 30 provisions of BCP 78 and BCP 79. 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF). Note that other groups may also distribute 34 working documents as Internet-Drafts. The list of current Internet- 35 Drafts is at https://datatracker.ietf.org/drafts/current/. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 This Internet-Draft will expire on December 31, 2018. 44 Copyright Notice 46 Copyright (c) 2018 IETF Trust and the persons identified as the 47 document authors. All rights reserved. 49 This document is subject to BCP 78 and the IETF Trust's Legal 50 Provisions Relating to IETF Documents 51 (https://trustee.ietf.org/license-info) in effect on the date of 52 publication of this document. Please review these documents 53 carefully, as they describe your rights and restrictions with respect 54 to this document. Code Components extracted from this document must 55 include Simplified BSD License text as described in Section 4.e of 56 the Trust Legal Provisions and are provided without warranty as 57 described in the Simplified BSD License. 59 Table of Contents 61 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 3. Representations for Proof-of-Possession Keys . . . . . . . . 3 64 3.1. Confirmation Claim . . . . . . . . . . . . . . . . . . . 4 65 3.2. Representation of an Asymmetric Proof-of-Possession Key . 5 66 3.3. Representation of an Encrypted Symmetric Proof-of- 67 Possession Key . . . . . . . . . . . . . . . . . . . . . 5 68 3.4. Representation of a Key ID for a Proof-of-Possession Key 6 69 3.5. Specifics Intentionally Not Specified . . . . . . . . . . 7 70 4. Security Considerations . . . . . . . . . . . . . . . . . . . 7 71 5. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8 72 6. Operational Considerations . . . . . . . . . . . . . . . . . 8 73 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 74 7.1. CBOR Web Token Claims Registration . . . . . . . . . . . 10 75 7.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 10 76 7.2. CWT Confirmation Methods Registry . . . . . . . . . . . . 10 77 7.2.1. Registration Template . . . . . . . . . . . . . . . . 10 78 7.2.2. Initial Registry Contents . . . . . . . . . . . . . . 11 79 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 80 8.1. Normative References . . . . . . . . . . . . . . . . . . 11 81 8.2. Informative References . . . . . . . . . . . . . . . . . 12 82 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13 83 Document History . . . . . . . . . . . . . . . . . . . . . . . . 13 84 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 86 1. Introduction 88 This specification describes how a CBOR Web Token (CWT) [RFC8392] can 89 declare that the presenter of the CWT possesses a particular proof- 90 of-possession (PoP) key. Proof of possession of a key is also 91 sometimes described as being the holder-of-key. This specification 92 provides equivalent functionality to "Proof-of-Possession Key 93 Semantics for JSON Web Tokens (JWTs)" [RFC7800], but using CBOR 94 [RFC7049] and CWTs [RFC8392] rather than JSON [RFC7159] and JWTs 95 [JWT]. 97 2. Terminology 99 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 100 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 101 "OPTIONAL" in this document are to be interpreted as described in BCP 102 14 [RFC2119] [RFC8174] when, and only when, they appear in all 103 capitals, as shown here. 105 This specification uses terms defined in the CBOR Web Token (CWT) 106 [RFC8392], CBOR Object Signing and Encryption (COSE) [RFC8152], and 107 Concise Binary Object Representation (CBOR) [RFC7049] specifications. 109 These terms are defined by this specification: 111 Issuer 112 Party that creates the CWT and binds the claims about the subject 113 to the proof-of-possession key. 115 Presenter 116 Party that proves possession of a private key (for asymmetric key 117 cryptography) or secret key (for symmetric key cryptography) to a 118 recipient. 119 In context of OAuth this party is also called OAuth Client. 121 Recipient 122 Party that receives the CWT containing the proof-of-possession key 123 information from the presenter. 124 In context of OAuth this party is also called OAuth Resource 125 Server. 127 3. Representations for Proof-of-Possession Keys 129 By including a "cnf" (confirmation) claim in a CWT, the issuer of the 130 CWT declares that the presenter possesses a particular key and that 131 the recipient can cryptographically confirm that the presenter has 132 possession of that key. The value of the "cnf" claim is a CBOR map 133 and the members of that map identify the proof-of-possession key. 135 The presenter can be identified in one of several ways by the CWT, 136 depending upon the application requirements. For instance, some 137 applications may use the CWT "sub" (subject) claim [RFC8392], to 138 identify the presenter. Other applications may use the "iss" claim 139 to identify the presenter. In some applications, the subject 140 identifier might be relative to the issuer identified by the "iss" 141 (issuer) claim [RFC8392]. The actual mechanism used is dependent 142 upon the application. The case in which the presenter is the subject 143 of the CWT is analogous to Security Assertion Markup Language (SAML) 144 2.0 [OASIS.saml-core-2.0-os] SubjectConfirmation usage. 146 3.1. Confirmation Claim 148 The "cnf" claim in the CWT is used to carry confirmation methods. 149 Some of them use proof-of-possession keys while others do not. This 150 design is analogous to the SAML 2.0 [OASIS.saml-core-2.0-os] 151 SubjectConfirmation element in which a number of different subject 152 confirmation methods can be included (including proof-of-possession 153 key information). 155 The set of confirmation members that a CWT must contain to be 156 considered valid is context dependent and is outside the scope of 157 this specification. Specific applications of CWTs will require 158 implementations to understand and process some confirmation members 159 in particular ways. However, in the absence of such requirements, 160 all confirmation members that are not understood by implementations 161 MUST be ignored. 163 This specification establishes the IANA "CWT Confirmation Methods" 164 registry for these members in Section 7.2 and registers the members 165 defined by this specification. Other specifications can register 166 other members used for confirmation, including other members for 167 conveying proof-of-possession keys using different key 168 representations. 170 The "cnf" claim value MUST represent only a single proof-of- 171 possession key. At most one of the "COSE_Key" and 172 "Encrypted_COSE_Key" confirmation values defined in Figure 1 may be 173 present. Note that if an application needs to represent multiple 174 proof-of-possession keys in the same CWT, one way for it to achieve 175 this is to use other claim names, in addition to "cnf", to hold the 176 additional proof-of-possession key information. These claims could 177 use the same syntax and semantics as the "cnf" claim. Those claims 178 would be defined by applications or other specifications and could be 179 registered in the IANA "CBOR Web Token Claims" registry 180 [IANA.CWT.Claims]. 182 /--------------------+-----+-------------------------------\ 183 | Name | Key | Value type | 184 |--------------------+-----+-------------------------------| 185 | COSE_Key | 1 | COSE_Key | 186 | Encrypted_COSE_Key | 2 | COSE_Encrypt or COSE_Encrypt0 | 187 | kid | 3 | binary string | 188 \--------------------+-----+-------------------------------/ 190 Figure 1: Summary of the cnf names, keys, and value types 192 3.2. Representation of an Asymmetric Proof-of-Possession Key 194 When the key held by the presenter is an asymmetric private key, the 195 "COSE_Key" member is a COSE_Key [RFC8152] representing the 196 corresponding asymmetric public key. The following example (using 197 CBOR diagnostic notation) demonstrates such a declaration in the CWT 198 Claims Set of a CWT: 200 { 201 /iss/ 1 : "coaps://server.example.com", 202 /aud/ 3 : "coaps://client.example.org", 203 /exp/ 4 : 1361398824, 204 /cnf/ 8 :{ 205 /COSE_Key/ 1 :{ 206 /kty/ 1 : /EC/ 2, 207 /crv/ -1 : /P-256/ 1, 208 /x/ -2 : h'd7cc072de2205bdc1537a543d53c60a6acb62eccd890c7fa27c9 209 e354089bbe13', 210 /y/ -3 : h'f95e1d4b851a2cc80fff87d8e23f22afb725d535e515d020731e 211 79a3b4e47120' 212 } 213 } 214 } 216 The COSE_Key MUST contain the required key members for a COSE_Key of 217 that key type and MAY contain other COSE_Key members, including the 218 "kid" (Key ID) member. 220 The "COSE_Key" member MAY also be used for a COSE_Key representing a 221 symmetric key, provided that the CWT is encrypted so that the key is 222 not revealed to unintended parties. The means of encrypting a CWT is 223 explained in [RFC8392]. If the CWT is not encrypted, the symmetric 224 key MUST be encrypted as described in Section 3.3. 226 3.3. Representation of an Encrypted Symmetric Proof-of-Possession Key 228 When the key held by the presenter is a symmetric key, the 229 "Encrypted_COSE_Key" member is an encrypted COSE_Key [RFC8152] 230 representing the symmetric key encrypted to a key known to the 231 recipient using COSE_Encrypt or COSE_Encrypt0. 233 The following example (using CBOR diagnostic notation, with 234 linebreaks for readability) illustrates a symmetric key that could 235 subsequently be encrypted for use in the "Encrypted_COSE_Key" member: 237 { 238 /kty/ 1 : /Symmetric/ 4, 239 /alg/ 3 : /HMAC256/ 5, 240 /k/ -1 : h'6684523ab17337f173500e5728c628547cb37df 241 e68449c65f885d1b73b49eae1A0B0C0D0E0F10' 242 } 244 The COSE_Key representation is used as the plaintext when encrypting 245 the key. The COSE_Key could, for instance, be encrypted using a 246 COSE_Encrypt0 representation using the AES-CCM-16-64-128 algorithm. 248 The following example CWT Claims Set of a CWT (using CBOR diagnostic 249 notation, with linebreaks for readability) illustrates the use of an 250 encrypted symmetric key as the "Encrypted_COSE_Key" member value: 252 { 253 /iss/ 1 : "coaps://server.example.com", 254 /sub/ 2 : "24400320", 255 /aud/ 3: "s6BhdRkqt3", 256 /exp/ 4 : 1311281970, 257 /iat/ 5 : 1311280970, 258 /cnf/ 8 : { 259 /COSE_Encrypt0/ 2 : [ 260 /protected header / h'A1010A' /{ \alg\ 1:10 \AES-CCM-16-64-128\}/, 261 /unprotected header/ { / iv / 5: h'636898994FF0EC7BFCF6D3F95B'}, 262 /ciphertext/ h'0573318A3573EB983E55A7C2F06CADD0796C9E584F1D0E3E 263 A8C5B052592A8B2694BE9654F0431F38D5BBC8049FA7F13F' 264 ] 265 } 266 } 268 The example above was generated with the key: 270 h'6162630405060708090a0b0c0d0e0f10' 272 3.4. Representation of a Key ID for a Proof-of-Possession Key 274 The proof-of-possession key can also be identified by the use of a 275 Key ID instead of communicating the actual key, provided the 276 recipient is able to obtain the identified key using the Key ID. In 277 this case, the issuer of a CWT declares that the presenter possesses 278 a particular key and that the recipient can cryptographically confirm 279 proof of possession of the key by the presenter by including a "cnf" 280 claim in the CWT whose value is a CBOR map with the CBOR map 281 containing a "kid" member identifying the key. 283 The following example (using CBOR diagnostic notation) demonstrates 284 such a declaration in the CWT Claims Set of a CWT: 286 { 287 /iss/ 1 : "coaps://server.example.com", 288 /aud/ 3 : "coaps://client.example.org", 289 /exp/ 4 : 1361398824, 290 /cnf/ 8 : { 291 /kid/ 2 : h'dfd1aa976d8d4575a0fe34b96de2bfad' 292 } 293 } 295 The content of the "kid" value is application specific. For 296 instance, some applications may choose to use a cryptographic hash of 297 the public key value as the "kid" value. 299 3.5. Specifics Intentionally Not Specified 301 Proof of possession is often demonstrated by having the presenter 302 sign a value determined by the recipient using the key possessed by 303 the presenter. This value is sometimes called a "nonce" or a 304 "challenge". 306 The means of communicating the nonce and the nature of its contents 307 are intentionally not described in this specification, as different 308 protocols will communicate this information in different ways. 309 Likewise, the means of communicating the signed nonce is also not 310 specified, as this is also protocol specific. 312 Note that another means of proving possession of the key when it is a 313 symmetric key is to encrypt the key to the recipient. The means of 314 obtaining a key for the recipient is likewise protocol specific. 316 4. Security Considerations 318 All of the security considerations that are discussed in [RFC8392] 319 also apply here. In addition, proof of possession introduces its own 320 unique security issues. Possessing a key is only valuable if it is 321 kept secret. Appropriate means must be used to ensure that 322 unintended parties do not learn private key or symmetric key values. 324 Applications utilizing proof of possession SHOULD also utilize 325 audience restriction, as described in Section 4.1.3 of [JWT], as it 326 provides additional protections. Proof of possession can be used by 327 recipients to reject messages from unauthorized senders. Audience 328 restriction can be used by recipients to reject messages intended for 329 different recipients. 331 A recipient might not understand the "cnf" claim. Applications that 332 require the proof-of-possession keys communicated with it to be 333 understood and processed MUST ensure that the parts of this 334 specification that they use are implemented. 336 CBOR Web Tokens with proof-of-possession keys are used in context of 337 an architecture, such as the ACE OAuth Framework 338 [I-D.ietf-ace-oauth-authz], in which protocols are used by a 339 presenter to request these tokens and to subsequently use them with 340 recipients. To avoid replay attacks when the proof-of-possession 341 tokens are sent to presenters, a security protocol, which uses 342 mechansims such as nonces or timestamps, has to be utilized. Note 343 that a discussion of the architecture or specific protocols that CWT 344 proof-of-possession tokens are used with is beyond the scope of this 345 specification. 347 As is the case with other information included in a CWT, it is 348 necessary to apply data origin authentication and integrity 349 protection (via a keyed message digest or a digital signature). Data 350 origin authentication ensures that the recipient of the CWT learns 351 about the entity that created the CWT since this will be important 352 for any policy decisions. Integrity protection prevents an adversary 353 from changing any elements conveyed within the CWT payload. Special 354 care has to be applied when carrying symmetric keys inside the CWT 355 since those not only require integrity protection but also 356 confidentiality protection. 358 As described in Section 6 (Key Identification) and Appendix D (Notes 359 on Key Selection) of [JWS], it is important to make explicit trust 360 decisions about the keys. Proof-of-possession signatures made with 361 keys not meeting the application's trust criteria MUST NOT be relied 362 upon. 364 5. Privacy Considerations 366 A proof-of-possession key can be used as a correlation handle if the 367 same key is used with multiple parties. Thus, for privacy reasons, 368 it is recommended that different proof-of-possession keys be used 369 when interacting with different parties. 371 6. Operational Considerations 373 The use of CWTs with proof-of-possession keys requires additional 374 information to be shared between the involved parties in order to 375 ensure correct processing. The recipient needs to be able to use 376 credentials to verify the authenticity, integrity, and potentially 377 the confidentiality of the CWT and its content. This requires the 378 recipient to know information about the issuer. Likewise, there 379 needs to be agreement between the issuer and the recipient about the 380 claims being used (which is also true of CWTs in general). 382 When an issuer creates a CWT containing a Key ID claim, it needs to 383 make sure that it does not issue another CWT containing the same Key 384 ID with a different content, or for a different subject, within the 385 lifetime of the CWTs, unless intentionally desired. Failure to do so 386 may allow one party to impersonate another party, with the potential 387 to gain additional privileges. Likewise, if PoP keys are used for 388 multiple different kinds of CWTs in an application and the PoP keys 389 are identified by Key IDs, care must be taken to keep the keys for 390 the different kinds of CWTs segregated so that an attacker cannot 391 cause the wrong PoP key to be used by using a valid Key ID for the 392 wrong kind of CWT. 394 7. IANA Considerations 396 The following registration procedure is used for all the registries 397 established by this specification. 399 Values are registered on a Specification Required [RFC5226] basis 400 after a three-week review period on the cwt-reg-review@ietf.org 401 mailing list, on the advice of one or more Designated Experts. 402 However, to allow for the allocation of values prior to publication, 403 the Designated Experts may approve registration once they are 404 satisfied that such a specification will be published. [[ Note to 405 the RFC Editor: The name of the mailing list should be determined in 406 consultation with the IESG and IANA. Suggested name: cwt-reg- 407 review@ietf.org. ]] 409 Registration requests sent to the mailing list for review should use 410 an appropriate subject (e.g., "Request to Register CWT Confirmation 411 Method: example"). Registration requests that are undetermined for a 412 period longer than 21 days can be brought to the IESG's attention 413 (using the iesg@ietf.org mailing list) for resolution. 415 Criteria that should be applied by the Designated Experts include 416 determining whether the proposed registration duplicates existing 417 functionality, determining whether it is likely to be of general 418 applicability or whether it is useful only for a single application, 419 and evaluating the security properties of the item being registered 420 and whether the registration makes sense. 422 It is suggested that multiple Designated Experts be appointed who are 423 able to represent the perspectives of different applications using 424 this specification in order to enable broadly informed review of 425 registration decisions. In cases where a registration decision could 426 be perceived as creating a conflict of interest for a particular 427 Expert, that Expert should defer to the judgment of the other 428 Experts. 430 7.1. CBOR Web Token Claims Registration 432 This specification registers the "cnf" claim in the IANA "CBOR Web 433 Token Claims" registry [IANA.CWT.Claims] established by [RFC8392]. 435 7.1.1. Registry Contents 437 o Claim Name: "cnf" 438 o Claim Description: Confirmation 439 o JWT Claim Name: "cnf" 440 o Claim Key: TBD (maybe 8) 441 o Claim Value Type(s): map 442 o Change Controller: IESG 443 o Specification Document(s): Section 3.1 of [[ this document ]] 445 7.2. CWT Confirmation Methods Registry 447 This specification establishes the IANA "CWT Confirmation Methods" 448 registry for CWT "cnf" member values. The registry records the 449 confirmation method member and a reference to the specification that 450 defines it. 452 7.2.1. Registration Template 454 Confirmation Method Name: 455 The human-readable name requested (e.g., "kid"). 457 Confirmation Method Description: 458 Brief description of the confirmation method (e.g., "Key 459 Identifier"). 461 JWT Confirmation Method Name: 462 Claim Name of the equivalent JWT confirmation method value, as 463 registered in [IANA.JWT.Claims]. CWT claims should normally have 464 a corresponding JWT claim. If a corresponding JWT claim would not 465 make sense, the Designated Experts can choose to accept 466 registrations for which the JWT Claim Name is listed as "N/A". 468 Confirmation Key: 469 CBOR map key value for the confirmation method. 471 Confirmation Value Type(s): 472 CBOR types that can be used for the confirmation method value. 474 Change Controller: 476 For Standards Track RFCs, list the "IESG". For others, give the 477 name of the responsible party. Other details (e.g., postal 478 address, email address, home page URI) may also be included. 480 Specification Document(s): 481 Reference to the document or documents that specify the parameter, 482 preferably including URIs that can be used to retrieve copies of 483 the documents. An indication of the relevant sections may also be 484 included but is not required. 486 7.2.2. Initial Registry Contents 488 o Confirmation Method Name: "COSE_Key" 489 o Confirmation Method Description: COSE_Key Representing Public Key 490 o JWT Confirmation Method Name: "jwk" 491 o Confirmation Key: 1 492 o Confirmation Value Type(s): map 493 o Change Controller: IESG 494 o Specification Document(s): Section 3.2 of [[ this document ]] 496 o Confirmation Method Name: "Encrypted_COSE_Key" 497 o Confirmation Method Description: Encrypted COSE_Key 498 o JWT Confirmation Method Name: "jwe" 499 o Confirmation Key: 2 500 o Confirmation Value Type(s): array (with an optional COSE_Encrypt 501 or COSE_Encrypt0 tag) 502 o Change Controller: IESG 503 o Specification Document(s): Section 3.3 of [[ this document ]] 505 o Confirmation Method Name: "kid" 506 o Confirmation Method Description: Key Identifier 507 o JWT Confirmation Method Name: "kid" 508 o Confirmation Key: 3 509 o Confirmation Value Type(s): binary string 510 o Change Controller: IESG 511 o Specification Document(s): Section 3.4 of [[ this document ]] 513 8. References 515 8.1. Normative References 517 [IANA.CWT.Claims] 518 IANA, "CBOR Web Token Claims", 519 . 521 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 522 Requirement Levels", BCP 14, RFC 2119, 523 DOI 10.17487/RFC2119, March 1997, 524 . 526 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 527 IANA Considerations Section in RFCs", RFC 5226, 528 DOI 10.17487/RFC5226, May 2008, 529 . 531 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object 532 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, 533 October 2013, . 535 [RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)", 536 RFC 8152, DOI 10.17487/RFC8152, July 2017, 537 . 539 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 540 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 541 May 2017, . 543 [RFC8392] Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, 544 "CBOR Web Token (CWT)", RFC 8392, DOI 10.17487/RFC8392, 545 May 2018, . 547 8.2. Informative References 549 [I-D.ietf-ace-oauth-authz] 550 Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and 551 H. Tschofenig, "Authentication and Authorization for 552 Constrained Environments (ACE) using the OAuth 2.0 553 Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-12 554 (work in progress), May 2018. 556 [IANA.JWT.Claims] 557 IANA, "JSON Web Token Claims", 558 . 560 [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web 561 Signature (JWS)", RFC 7515, May 2015, 562 . 564 [JWT] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token 565 (JWT)", RFC 7519, DOI 10.17487/RFC7159, May 2015, 566 . 568 [OASIS.saml-core-2.0-os] 569 Cantor, S., Kemp, J., Philpott, R., and E. Maler, 570 "Assertions and Protocol for the OASIS Security Assertion 571 Markup Language (SAML) V2.0", OASIS Standard saml-core- 572 2.0-os, March 2005, 573 . 575 [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data 576 Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March 577 2014, . 579 [RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of- 580 Possession Key Semantics for JSON Web Tokens (JWTs)", 581 RFC 7800, DOI 10.17487/RFC7800, April 2016, 582 . 584 Acknowledgements 586 Thanks to the following people for their reviews of the 587 specification: Roman Danyliw, Michael Richardson, and Jim Schaad. 589 Ludwig Seitz and Goeran Selander worked on this document as part of 590 the CelticPlus project CyberWI, with funding from Vinnova. 592 Document History 594 [[ to be removed by the RFC Editor before publication as an RFC ]] 596 -03 598 o Addressed review comments by Jim Schaad, see https://www.ietf.org/ 599 mail-archive/web/ace/current/msg02798.html 601 o Removed unnecessary sentence in the introduction regarding the use 602 any strings that could be case-sensitive. 604 o Clarified the terms Presenter and Recipient. 606 o Clarified text about the confirmation claim. 608 -02 610 o Changed "typically" to "often" when describing ways of performing 611 proof of possession. 613 o Changed b64 to hex encoding in an example. 615 o Changed to using the RFC 8174 boilerplate instead of the RFC 2119 616 boilerplate. 618 -01 620 o Now uses CBOR diagnostic notation for the examples. 622 o Added a table summarizing the "cnf" names, keys, and value types. 624 o Addressed some of Jim Schaad's feedback on -00. 626 -00 628 o Created the initial working group draft from draft-jones-ace-cwt- 629 proof-of-possession-01. 631 Authors' Addresses 633 Michael B. Jones 634 Microsoft 636 Email: mbj@microsoft.com 637 URI: http://self-issued.info/ 639 Ludwig Seitz 640 RISE SICS 641 Scheelevaegen 17 642 Lund 223 70 643 Sweden 645 Email: ludwig@ri.se 647 Goeran Selander 648 Ericsson AB 649 Faeroegatan 6 650 Kista 164 80 651 Sweden 653 Email: goran.selander@ericsson.com 655 Samuel Erdtman 656 Spotify 658 Email: erdtman@spotify.com 659 Hannes Tschofenig 660 ARM Ltd. 661 Hall in Tirol 6060 662 Austria 664 Email: Hannes.Tschofenig@arm.com