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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ACE Working Group L. Seitz 3 Internet-Draft RISE SICS AB 4 Intended status: Standards Track F. Palombini 5 Expires: January 24, 2018 Ericsson AB 6 M. Gunnarsson 7 RISE SICS AB 8 July 23, 2017 10 OSCOAP profile of the Authentication and Authorization for Constrained 11 Environments Framework 12 draft-seitz-ace-oscoap-profile-04 14 Abstract 16 This memo specifies a profile for the Authentication and 17 Authorization for Constrained Environments (ACE) framework. It 18 utilizes Object Security of CoAP (OSCOAP) and Ephemeral Diffie- 19 Hellman over COSE (EDHOC) to provide communication security, server 20 authentication, and proof-of-possession for a key owned by the client 21 and bound to an OAuth 2.0 access token. 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 http://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 January 24, 2018. 40 Copyright Notice 42 Copyright (c) 2017 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 (http://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. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 59 2. Client to Resource Server . . . . . . . . . . . . . . . . . . 3 60 2.1. Signaling the use of OSCOAP . . . . . . . . . . . . . . . 3 61 2.2. Key establishment for OSCOAP . . . . . . . . . . . . . . 4 62 2.2.1. Using the pop-key with OSCOAP directly (OSCOAP) . . . 4 63 2.2.2. Using the pop-key with EDHOC (EDHOC+OSCOAP) . . . . . 7 64 2.3. Client to Authorization Server . . . . . . . . . . . . . 13 65 3. Resource Server to Authorization Server . . . . . . . . . . . 14 66 4. Security Considerations . . . . . . . . . . . . . . . . . . . 14 67 5. Privacy Considerations . . . . . . . . . . . . . . . . . . . 14 68 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 69 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14 70 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 71 8.1. Normative References . . . . . . . . . . . . . . . . . . 15 72 8.2. Informative References . . . . . . . . . . . . . . . . . 15 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 75 1. Introduction 77 This memo specifies a profile of the ACE framework 78 [I-D.ietf-ace-oauth-authz]. In this profile, a client and a resource 79 server use CoAP [RFC7252] to communicate. The client uses an access 80 token, bound to a key (the proof-of-possession key) to authorize its 81 access to the resource server. In order to provide communication 82 security, proof of possession, and server authentication they use 83 Object Security of CoAP (OSCOAP) [I-D.ietf-core-object-security] and 84 Ephemeral Diffie-Hellman Over COSE (EDHOC) 85 [I-D.selander-ace-cose-ecdhe]. Optionally the client and the 86 resource server may also use CoAP and OSCOAP to communicate with the 87 authorization server. The use of EDHOC in this profile in addition 88 to OSCOAP, provides perfect forward secrecy (PFS) and the initial 89 proof-of-possession, which ties the proof-of-possession key to an 90 OSCOAP security context. 92 OSCOAP specifies how to use CBOR Object Signing and Encryption (COSE) 93 [RFC8152] to secure CoAP messages. In order to provide replay and 94 reordering protection OSCOAP also introduces sequence numbers that 95 are used together with COSE. EDHOC specifies an authenticated 96 Diffie-Hellman protocol that allows two parties to use CBOR [RFC7049] 97 and COSE in order to establish a shared secret key with perfect 98 forward secrecy. 100 1.1. Terminology 102 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 103 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 104 document are to be interpreted as described in [RFC2119]. These 105 words may also appear in this document in lowercase, absent their 106 normative meanings. 108 Certain security-related terms such as "authentication", 109 "authorization", "confidentiality", "(data) integrity", "message 110 authentication code", and "verify" are taken from [RFC4949]. 112 Since we describe exchanges as RESTful protocol interactions HTTP 113 [RFC7231] offers useful terminology. 115 Terminology for entities in the architecture is defined in OAuth 2.0 116 [RFC6749] and [I-D.ietf-ace-actors], such as client (C), resource 117 server (RS), and authorization server (AS). It is assumed in this 118 document that a given resource on a specific RS is associated to a 119 unique AS. 121 Note that the term "endpoint" is used here following its OAuth 122 definition, which is to denote resources such as /token and 123 /introspect at the AS and /authz-info at the RS. The CoAP [RFC7252] 124 definition, which is "An entity participating in the CoAP protocol" 125 is not used in this memo. 127 2. Client to Resource Server 129 The use of OSCOAP for arbitrary CoAP messages is specified in 130 [I-D.ietf-core-object-security]. This section defines the specific 131 uses and their purpose for securing the communication between a 132 client and a resource server, and the parameters needed to negotiate 133 the use of this profile with the token endpoint at the authorization 134 server as specified in section 5.5 of the ACE framework 135 [I-D.ietf-ace-oauth-authz]. 137 2.1. Signaling the use of OSCOAP 139 A client requests a token at an AS via the /token endpoint. This 140 follows the message formats specified in section 5.5.1 of the ACE 141 framework [I-D.ietf-ace-oauth-authz]. 143 The AS responding to a successful access token request as defined in 144 section 5.5.2 of the ACE framework can signal that the use of OSCOAP 145 is REQUIRED for a specific access token by including the "profile" 146 parameter with the value "coap_oscoap" or "coap_oscoap_edhoc" in the 147 access token response. This means that the client MUST use OSCOAP 148 towards all resource servers for which this access token is valid, 149 and follow Section 2.2.1 to derive the security context to run 150 OSCOAP, if the profile has value "coap_oscoap", or follow 151 Section 2.2.2 to derive the security context to run OSCOAP, if the 152 profile has value "coap_oscoap_edhoc". 154 The error response procedures defined in section 5.5.3 of the ACE 155 framework are unchanged by this profile. 157 Note the the client and the authorization server MAY OPTIONALLY use 158 OSCOAP to protect the interaction via the /token endpoint. See 159 section 3 for details. 161 2.2. Key establishment for OSCOAP 163 Section 3.2 of OSCOAP [I-D.ietf-core-object-security] defines how to 164 derive a security context based on a shared master secret and a few 165 other parameters, established between client and server. The proof- 166 of-possession key (pop-key) provisioned from the AS MAY, in case of 167 pre-shared keys, be used directly as master secret in OSCOAP. 168 Alternatively the pop-key (symmetric or asymmetric) MAY be used to 169 authenticate the messages in the key exchange protocol EDHOC 170 [I-D.selander-ace-cose-ecdhe], from which a master secret is derived. 172 2.2.1. Using the pop-key with OSCOAP directly (OSCOAP) 174 If OSCOAP is used directly with the symmetric pop-key as master 175 secret, then the AS MUST provision the following data, in response to 176 the access token request: 178 o a master secret 180 o the sender identifier 182 o the recipient identifier 184 Additionally, the AS MAY provision the following data, in the same 185 response. In case these parameters are omitted, the default values 186 are used as described in section 3.2. of 187 [I-D.ietf-core-object-security]. 189 o an AEAD algorithm 191 o a KDF algorithm 192 o a salt 194 The master secret MUST be communicated as COSE_Key in the 'cnf' 195 parameter of the access token response as defined in section 5.5.4.5 196 of [I-D.ietf-ace-oauth-authz]. The AEAD algorithm MAY be included as 197 the 'alg' parameter in the COSE_Key; the KDF algorithm MAY be 198 included as the 'kdf' parameter of the COSE_Key and the salt MAY be 199 included as the 'slt' parameter of the COSE_Key as defined in table 200 1. The same parameters MUST be included as metadata of the access 201 token, if the token is a CWT [I-D.ietf-ace-cbor-web-token], the same 202 COSE_Key structure MUST be placed in the 'cnf' claim of this token. 203 The AS MUST also assign identifiers to both client and RS, which are 204 then used as Sender ID and Recipient ID in the OSCOAP context as 205 described in section 3.1. of [I-D.ietf-core-object-security]. These 206 identifiers MUST be unique in the set of all clients and RS 207 identifiers for a certain AS. Moreover, these MUST be included in 208 the COSE_Key as header parameters, as defined in table 1. 210 We assume in this document that a resource is associated to one 211 single AS, which makes it possible to assume unique identifiers for 212 each client requesting a particular resource to a RS. If this is not 213 the case, collisions of identifiers may appear in the RS, in which 214 case the RS needs to have a mechanism in place to disambiguate 215 identifiers or mitigate their effect. 217 Note that C should set the Sender ID of its security context to the 218 clientId value received and the Recipient ID to the serverId value, 219 and RS should do the opposite. 221 +----------+-------+----------------+------------+-------------------+ 222 | name | label | CBOR type | registry | description | 223 +----------+-------+----------------+------------+-------------------+ 224 | clientId | TBD | bstr | | Identifies the | 225 | | | | | client in an | 226 | | | | | OSCOAP context | 227 | | | | | using this key | 228 | | | | | | 229 | serverId | TBD | bstr | | Identifies the | 230 | | | | | server in an | 231 | | | | | OSCOAP context | 232 | | | | | using this key | 233 | | | | | | 234 | kdf | TBD | bstr | | Identifies the | 235 | | | | | KDF algorithm in | 236 | | | | | an OSCOAP context | 237 | | | | | using this key | 238 | | | | | | 239 | slt | TBD | bstr | | Identifies the | 240 | | | | | master salt in | 241 | | | | | an OSCOAP context | 242 | | | | | using this key | 243 +----------+-------+----------------+------------+-------------------+ 244 Table 1: Additional common header parameters for COSE_Key 246 Figure 1 shows an example of such an AS response, in CBOR diagnostic 247 notation without the tag and value abbreviations. 249 Header: Created (Code=2.01) 250 Content-Type: "application/cose+cbor" 251 Payload: 252 { 253 "access_token" : b64'SlAV32hkKG ... 254 (remainder of access token omitted for brevity)', 255 "profile" : "coap_oscoap", 256 "expires_in" : "3600", 257 "cnf" : { 258 "COSE_Key" : { 259 "kty" : "Symmetric", 260 "alg" : "AES-CCM-16-64-128", 261 "clientId" : b64'qA', 262 "serverId" : b64'Qg', 263 "k" : b64'+a+Dg2jjU+eIiOFCa9lObw' 264 } 265 } 266 } 268 Figure 1: Example AS response with OSCOAP parameters. 270 Figure 2 shows an example CWT, containing the necessary OSCOAP 271 parameters in the 'cnf' claim, in CBOR diagnostic notation without 272 tag and value abbreviations. 274 { 275 "aud" : "tempSensorInLivingRoom", 276 "iat" : "1360189224", 277 "exp" : "1360289224", 278 "scope" : "temperature_g firmware_p", 279 "cnf" : { 280 "COSE_Key" : { 281 "kty" : "Symmetric", 282 "alg" : "AES-CCM-16-64-128", 283 "clientId" : b64'Qg', 284 "serverId" : b64'qA', 285 "k" : b64'+a+Dg2jjU+eIiOFCa9lObw' 286 } 287 } 289 Figure 2: Example CWT with OSCOAP parameters. 291 2.2.2. Using the pop-key with EDHOC (EDHOC+OSCOAP) 293 If EDHOC is used together with OSCOAP, and the pop-key (symmetric or 294 asymmetric) is used to authenticate the messages in EDHOC, then the 295 AS MUST provision the following data, in response to the access token 296 request: 298 o a symmetric or asymmetric key (associated to the RS) 300 o a key identifier; 302 How these parameters are communicated depends on the type of key 303 (asymmetric or symmetric). 305 Note that in the case described in this section, the 'expires_in' 306 parameter, defined in section 4.2.2. of [RFC6749] defines the 307 lifetime in seconds of both the access token and the shared secret. 308 After expiration, C MUST acquire a new access token from the AS, and 309 run EDHOC again, as specified in this section 311 2.2.2.1. Using Asymmetric Keys 313 In case of an asymmetric key, C MUST communicate its own asymmetric 314 key to the AS in the 'cnf' parameter of the access token request, as 315 specified in section 5.5.1 of [I-D.ietf-ace-oauth-authz]; the AS MUST 316 communicate the RS's public key to C in the response, in the 'rs_cnf' 317 parameter, as specified in section 5.5.1 of 318 [I-D.ietf-ace-oauth-authz]. Note that the RS's public key MUST 319 include a 'kid' parameter, and that the value of the 'kid' MUST be 320 included in the access token, to let the RS know which of its public 321 keys C used. If the access token is a CWT 322 [I-D.ietf-ace-cbor-web-token], the key identifier MUST be placed 323 directly in the 'cnf' structure (if the key is only referenced). 325 Figure 3 shows an example of such a request in CBOR diagnostic 326 notation without tag and value abbreviations. 328 Header: POST (Code=0.02) 329 Uri-Host: "server.example.com" 330 Uri-Path: "token" 331 Content-Type: "application/cose+cbor" 332 Payload: 333 { 334 "grant_type" : "client_credentials", 335 "cnf" : { 336 "COSE_Key" : { 337 "kid" : "client_key" 338 "kty" : "EC", 339 "crv" : "P-256", 340 "x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8', 341 "y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4' 342 } 343 } 344 } 346 Figure 3: Example access token request (OSCOAP+EDHOC, asymmetric). 348 Figure 4 shows an example of a corresponding response in CBOR 349 diagnostic notation without tag and value abbreviations. 351 Header: Created (Code=2.01) 352 Content-Type: "application/cose+cbor" 353 Payload: 354 { 355 "access_token" : b64'SlAV32hkKG ... 356 (contains "kid" : "server_key")', 357 "profile" : "coap_oscoap_edhoc", 358 "expires_in" : "3600", 359 "rs_cnf" : { 360 "COSE_Key" : { 361 "kid" : "server_key" 362 "kty" : "EC", 363 "crv" : "P-256", 364 "x" : b64'cGJ90UiglWiGahtagnv8usWxHK2PmfnHKwXPS54m0kT', 365 "y" : b64'reASjpkttcsz+1rb7btKLv8EX4IBOL+C3BttVivg+lS' 366 } 367 } 368 } 370 Figure 4: Example AS response (EDHOC+OSCOAP, asymmetric). 372 2.2.2.2. Using Symmetric Keys 374 In the case of a symmetric key, the AS MUST communicate the key to 375 the client in the 'cnf' parameter of the access token response, as 376 specified in section 5.5.2. of [I-D.ietf-ace-oauth-authz]. AS MUST 377 also select a key identifier, that MUST be included as the 'kid' 378 parameter either directly in the 'cnf' structure, as in figure 4 of 379 [I-D.ietf-ace-oauth-authz], or as the 'kid' parameter of the 380 COSE_key, as in figure 6 of [I-D.ietf-ace-oauth-authz]. 382 Figure 5 shows an example of the necessary parameters in the AS 383 response to the access token request when EDHOC is used. The example 384 uses CBOR diagnostic notation without tag and value abbreviations. 386 Header: Created (Code=2.01) 387 Content-Type: "application/cose+cbor" 388 Payload: 389 { 390 "access_token" : b64'SlAV32hkKG ... 391 (remainder of access token omitted for brevity)', 392 "profile" : "coap_oscoap_edhoc", 393 "expires_in" : "3600", 394 "cnf" : { 395 "COSE_Key" : { 396 "kty" : "Symmetric", 397 "kid" : b64'5tOS+h42dkw', 398 "k" : b64'+a+Dg2jjU+eIiOFCa9lObw' 399 } 400 } 401 } 403 Figure 5: Example AS response (EDHOC+OSCOAP, symmetric). 405 In both cases, the AS MUST also include the same key identifier as 406 'kid' parameter in the access token metadata. If the access token is 407 a CWT [I-D.ietf-ace-cbor-web-token], the key identifier MUST be 408 placed inside the 'cnf' claim as 'kid' parameter of the COSE_Key or 409 directly in the 'cnf' structure (if the key is only referenced). 411 Figure 6 shows an example CWT containing the necessary EDHOC+OSCOAP 412 parameters in the 'cnf' claim, in CBOR diagnostic notation without 413 tag and value abbreviations. 415 { 416 "aud" : "tempSensorInLivingRoom", 417 "iat" : "1360189224", 418 "exp" : "1360289224", 419 "scope" : "temperature_g firmware_p", 420 "cnf" : { 421 "COSE_Key" : { 422 "kty" : "Symmetric", 423 "kid" : b64'5tOS+h42dkw', 424 "k" : b64'+a+Dg2jjU+eIiOFCa9lObw' 425 } 426 } 428 Figure 6: Example CWT with EDHOC+OSCOAP, symmetric case. 430 All other parameters defining OSCOAP security context are derived 431 from EDHOC message exchange, including the master secret (see 432 Appendix C.2 of [I-D.selander-ace-cose-ecdhe]). 434 2.2.2.3. Processing 436 To provide forward secrecy and mutual authentication in the case of 437 pre-shared keys, pre-established raw public keys or with X.509 438 certificates it is RECOMMENDED to use EDHOC 439 [I-D.selander-ace-cose-ecdhe] to generate the keying material. EDHOC 440 MUST be used as defined in Appendix C, with the following additions 441 and modifications. 443 The first EDHOC message is sent after the access token is posted to 444 the /authz-info endpoint of the RS as specified in section 5.7.1 of, 445 as defined in [I-D.ietf-ace-oauth-authz]. Then the EDHOC message_1 446 is sent and the EDHOC protocol is initiated 447 [I-D.selander-ace-cose-ecdhe]). 449 Before the RS continues with the EDHOC protocol and responds to this 450 token submission request, additional verifications on the access 451 token are done: the RS SHALL process the access token according to 452 [I-D.ietf-ace-oauth-authz]. If the token is valid then the RS 453 continues processing EDHOC following Appendix C of 454 [I-D.selander-ace-cose-ecdhe], otherwise it discontinues EDHOC and 455 responds with the error code as specified in 456 [I-D.ietf-ace-oauth-authz]. 458 o In case the EDHOC verification fails, the RS MUST return an error 459 response to the client with code 4.01 (Unauthorized). 461 o If RS has an access token for C but not for the resource that C 462 has requested, RS MUST reject the request with a 4.03 (Forbidden). 464 o If RS has an access token for C but it does not cover the action C 465 requested on the resource, RS MUST reject the request with a 4.05 466 (Method Not Allowed). 468 o If all verifications above succeeds, further communication between 469 client and RS is protected with OSCOAP, including the RS response 470 to the OSCOAP request. 472 In the case of EDHOC being used with symmetric keys, the protocol in 473 section 5 of [I-D.selander-ace-cose-ecdhe] MUST be used. If the key 474 is asymmetric, the RS MUST also use an asymmetric key for 475 authentication. This key is known to the client through the access 476 token response (see section 5.5.2 of the ACE framework). In this 477 case the protocol in section 4 of [I-D.selander-ace-cose-ecdhe] MUST 478 be used. 480 Figure 7 illustrates the message exchanges for using OSCOAP+EDHOC 481 (step C in figure 1 of [I-D.ietf-ace-oauth-authz]). 483 Resource 484 Client Server 485 | | 486 | | 487 +--------->| Header: POST (Code=0.02) 488 | POST | Uri-Path:"authz-info" 489 | | Content-Type: application/cbor 490 | | Payload: access token 491 | | 492 | | 493 +--------->| Header: POST (Code=0.02) 494 | POST | Uri-Path: "/.well-known/edhoc" 495 | | Content-Type: application/edhoc 496 | | Payload: EDHOC message_1 497 | | 498 |<---------+ Header: 2.04 Changed 499 | 2.04 | Content-Type: application/edhoc 500 | | Payload: EDHOC message_2 501 | | 502 +--------->| Header: POST (Code=0.02) 503 | POST | Uri-Path: "/.well-known/edhoc" 504 | | Content-Type: application/edhoc 505 | | Payload: EDHOC message_3 506 | | 507 |<---------+ Header: 2.04 Changed 508 | 2.04 | 509 | | 510 start of protected communication 511 | | 512 +--------->| CoAP request + 513 | OSCOAP | Object-Security option 514 | request | 515 | | 516 |<---------+ CoAP response + 517 | OSCOAP | Object-Security option 518 | response | 519 | | 521 Figure 7: Access token and key establishment with EDHOC 523 2.3. Client to Authorization Server 525 As specified in the ACE framework section 5.5 526 [I-D.ietf-ace-oauth-authz], the Client and AS can also use CoAP 527 instead of HTTP to communicate via the token endpoint. This section 528 specifies how to use OSCOAP between Client and AS together with CoAP. 529 The use of OSCOAP for this communication is OPTIONAL in this profile, 530 other security protocols (such as DTLS) MAY be used instead. 532 The client and the AS are expected to have pre-established 533 credentials (e.g. raw public keys). How these credentials are 534 established is out of scope for this profile. Furthermore the client 535 and the AS communicate using CoAP through the token endpoint as 536 specified in section 5.5 of [I-D.ietf-ace-oauth-authz]. At first 537 point of contact, prior to making the token request and response, the 538 client and the AS MAY perform an EDHOC exchange with the pre- 539 established credentials to create forward secret keying material for 540 use with OSCOAP. Subsequent requests and the responses MUST be 541 protected with OSCOAP. 543 3. Resource Server to Authorization Server 545 As specified in the ACE framework section 5.6 546 [I-D.ietf-ace-oauth-authz], the RS and AS can also use CoAP instead 547 of HTTP to communicate via the introspection endpoint. This section 548 specifies how to use OSCOAP between RS and AS together with CoAP. 549 The use of OSCOAP for this communication is OPTIONAL in this profile, 550 other security protocols (such as DTLS) MAY be used instead. 552 The RS and the AS are expected to have pre-established credentials 553 (e.g. symmetric keys). How these credentials are established is out 554 of scope for this profile. Furthermore the RS and the AS communicate 555 using CoAP through the introspection endpoint as specified in section 556 5.6 of [I-D.ietf-ace-oauth-authz]. At first point of contact, prior 557 to making the introspection request and response, the RS and the AS 558 MAY perform an EDHOC exchange with the pre-established credentials to 559 create forward secret keying material for use with OSCOAP. 560 Subsequent requests and the responses MUST be protected with OSCOAP 562 4. Security Considerations 564 TBD. 566 5. Privacy Considerations 568 TBD. 570 6. IANA Considerations 572 TBD. 'coap_oscoap' as profile id. Header parameters 'sid', 'rid', 573 'kdf' and 'slt' for COSE_Key. 575 7. Acknowledgments 577 The author wishes to thank Jim Schaad, Goeran Selander and Marco 578 Tiloca for the input on this memo. The error responses specified in 579 section 2.2. were originally specified by Gerdes et al. in 580 [I-D.gerdes-ace-dcaf-authorize]. 582 8. References 584 8.1. Normative References 586 [I-D.ietf-ace-cbor-web-token] 587 Jones, M., Wahlstroem, E., Erdtman, S., and H. Tschofenig, 588 "CBOR Web Token (CWT)", draft-ietf-ace-cbor-web-token-07 589 (work in progress), July 2017. 591 [I-D.ietf-ace-oauth-authz] 592 Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and 593 H. Tschofenig, "Authentication and Authorization for 594 Constrained Environments (ACE)", draft-ietf-ace-oauth- 595 authz-06 (work in progress), March 2017. 597 [I-D.ietf-core-object-security] 598 Selander, G., Mattsson, J., Palombini, F., and L. Seitz, 599 "Object Security of CoAP (OSCOAP)", draft-ietf-core- 600 object-security-04 (work in progress), July 2017. 602 [I-D.selander-ace-cose-ecdhe] 603 Selander, G., Mattsson, J., and F. Palombini, "Ephemeral 604 Diffie-Hellman Over COSE (EDHOC)", draft-selander-ace- 605 cose-ecdhe-07 (work in progress), July 2017. 607 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 608 Requirement Levels", BCP 14, RFC 2119, 609 DOI 10.17487/RFC2119, March 1997, 610 . 612 [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained 613 Application Protocol (CoAP)", RFC 7252, 614 DOI 10.17487/RFC7252, June 2014, 615 . 617 [RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)", 618 RFC 8152, DOI 10.17487/RFC8152, July 2017, 619 . 621 8.2. Informative References 623 [I-D.gerdes-ace-dcaf-authorize] 624 Gerdes, S., Bergmann, O., and C. Bormann, "Delegated CoAP 625 Authentication and Authorization Framework (DCAF)", draft- 626 gerdes-ace-dcaf-authorize-04 (work in progress), October 627 2015. 629 [I-D.ietf-ace-actors] 630 Gerdes, S., Seitz, L., Selander, G., and C. Bormann, "An 631 architecture for authorization in constrained 632 environments", draft-ietf-ace-actors-05 (work in 633 progress), March 2017. 635 [RFC4949] Shirey, R., "Internet Security Glossary, Version 2", 636 FYI 36, RFC 4949, DOI 10.17487/RFC4949, August 2007, 637 . 639 [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", 640 RFC 6749, DOI 10.17487/RFC6749, October 2012, 641 . 643 [RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object 644 Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049, 645 October 2013, . 647 [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 648 Protocol (HTTP/1.1): Semantics and Content", RFC 7231, 649 DOI 10.17487/RFC7231, June 2014, 650 . 652 Authors' Addresses 654 Ludwig Seitz 655 RISE SICS AB 656 Scheelevagen 17 657 Lund 22370 658 SWEDEN 660 Email: ludwig.seitz@ri.se 662 Francesca Palombini 663 Ericsson AB 664 Farogatan 6 665 Kista SE-16480 Stockholm 666 Sweden 668 Email: francesca.palombini@ericsson.com 669 Martin Gunnarsson 670 RISE SICS AB 671 Scheelevagen 17 672 Lund 22370 673 SWEDEN 675 Email: martin.gunnarsson@ri.se