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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 informational reference (is this intentional?): RFC 3447 (Obsoleted by RFC 8017) -- Obsolete informational reference (is this intentional?): RFC 5246 (Obsoleted by RFC 8446) -- Obsolete informational reference (is this intentional?): RFC 5996 (Obsoleted by RFC 7296) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group T. Kivinen 3 Internet-Draft INSIDE Secure 4 Updates: 7296 (if approved) P. Wouters 5 Intended status: Standards Track Red Hat 6 Expires: April 08, 2016 H. Tschofenig 8 October 06, 2015 10 More Raw Public Keys for IKEv2 11 draft-kivinen-ipsecme-oob-pubkey-13.txt 13 Abstract 15 The Internet Key Exchange Version 2 (IKEv2) protocol only supports 16 RSA for raw public keys. In constrained environments it is useful to 17 make use of other types of public keys, such as those based on 18 Elliptic Curve Cryptography. This documents adds support for other 19 types of raw public keys to IKEv2. 21 This document updates RFC 7296 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 April 08, 2016. 40 Copyright Notice 42 Copyright (c) 2015 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 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 3. Certificate Encoding Payload . . . . . . . . . . . . . . . . 3 60 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 61 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 62 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 63 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 64 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 65 7.2. Informative References . . . . . . . . . . . . . . . . . 6 66 Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 7 67 A.1. ECDSA Example . . . . . . . . . . . . . . . . . . . . . . 7 68 A.2. RSA Example . . . . . . . . . . . . . . . . . . . . . . . 8 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 71 1. Introduction 73 This document replaces an algorithm-specific version of raw public 74 keys of Internet Key Exchange Version 2 (IKEv2) [RFC7296] with a 75 generic version of raw public keys that is algorithm agnostic. 77 In [RFC5996] IKEv2 had support for PKCS #1 encoded RSA keys, i.e., a 78 DER-encoded RSAPublicKey structure (see [RSA] and [RFC3447]). Other 79 raw public key types are, however, not supported. In [RFC7296] this 80 feature was removed, and this document adds support for raw public 81 keys back to IKEv2 in a more generic way. 83 Secure DNS allows public keys to be associated with domain names for 84 usage with security protocols like IKEv2 and Transport Layer Security 85 (TLS) [RFC5246] but it relies on extensions in those protocols to be 86 specified. 88 The Raw Public Keys in Transport Layer Security specification 89 ([RFC7250]) adds generic support for raw public keys to TLS by re- 90 using the SubjectPublicKeyInfo format from the X.509 Public Key 91 Infrastructure Certificate profile [RFC5280]. 93 This document is similar to the Raw Public Keys in Transport Layer 94 Security specification and applies the concept to IKEv2 to support 95 all public key formats defined by PKIX. This approach also allows 96 future public key extensions to be supported without the need to 97 introduce further enhancements to IKEv2. 99 To support new types of public keys in IKEv2 the following changes 100 are needed: 102 o A new Certificate Encoding format needs to be defined for carrying 103 the SubjectPublicKeyInfo structure. Section 3 specifies this new 104 encoding format. 106 o A new Certificate Encoding type needs to be allocated from the 107 IANA registry. Section 5 contains this request to IANA. 109 The base IKEv2 specification includes support for RSA and DSA 110 signatures, but the Signature Authentication in IKEv2 [RFC7427] 111 extended IKEv2 so that signature methods over any key type can be 112 used. Implementations using raw public keys SHOULD use the Digital 113 Signature method described in the RFC7427. 115 When using raw public keys, the authenticated identity is not usually 116 the identity from the ID payload, but instead the public key itself 117 is used as identity for the other end. This means that ID payload 118 contents might not be useful for authentication purposes. It might 119 still be used for policy decisions, for example to simplify the 120 policy lookup etc. Alternatively, the ID_NULL type [RFC7619] can be 121 used to indicate that the ID payload is not relevant to this 122 authentication. 124 2. Terminology 126 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 127 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 128 document are to be interpreted as described in [RFC2119]. 130 3. Certificate Encoding Payload 132 Section 3.6 of RFC 7296 defines the Certificate payload format as 133 shown in Figure 1. 135 1 2 3 136 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 | Next Payload |C| RESERVED | Payload Length | 139 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 140 | Cert Encoding | | 141 +-+-+-+-+-+-+-+-+ | 142 ~ Certificate Data ~ 143 | | 144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 Figure 1: Certificate Payload Format. 148 To support raw public keys, the field values are as follows: 150 o Certificate Encoding (1 octet) - This field indicates the type of 151 certificate or certificate-related information contained in the 152 Certificate Data field. 154 Certificate Encoding Value 155 ---------------------------------------------------- 156 Raw Public Key TBD 158 o Certificate Data (variable length) - Actual encoding of the 159 certificate data. 161 In order to provide a simple and standard way to indicate the key 162 type when the encoding type is 'Raw Public Key', the 163 SubjectPublicKeyInfo structure of the PKIX certificate is used. This 164 is a very simple encoding, as most of the ASN.1 part can be included 165 literally, and recognized by block comparison. See [RFC7250] 166 Appendix A for a detailed breakdown. In addition, Appendix A has 167 several examples. 169 In addition to the Certificate payload, the Cert Encoding for Raw 170 Public Key can be used in the Certificate Request payload. In that 171 case the Certification Authority field MUST be empty if the "Raw 172 Public Key" certificate encoding is used. 174 For RSA keys, the implementations MUST follow the public key 175 processing rules of section 1.2 of the Additional Algorithms and 176 Identifiers for RSA Cryptography for PKIX ([RFC4055]) even when the 177 SubjectPublicKeyInfo is not part of a certificate, but rather sent as 178 a Certificate Data field. This means that RSASSA-PSS and RSASSA-PSS- 179 params inside the SubjectPublicKeyInfo structure MUST be sent when 180 applicable. 182 4. Security Considerations 184 An IKEv2 deployment using raw public keys needs to utilize an out-of- 185 band public key validation procedure to be confident in the 186 authenticity of the keys being used. One way to achieve this goal is 187 to use a configuration mechanism for provisioning raw public keys 188 into the IKEv2 software. "Smart object" deployments are likely to 189 use such preconfigured public keys. 191 Another approach is to rely on secure DNS to associate public keys 192 with domain names using the IPSECKEY DNS RRtype [RFC4025]. More 193 information can be found in DNS-Based Authentication of Named 194 Entities (DANE) [RFC6394]. 196 This document does not change the security assumptions made by the 197 IKEv2 specification since "Raw RSA Key" support was already available 198 in IKEv2 in [RFC5996]. This document only generalizes raw public key 199 support. 201 5. IANA Considerations 203 This document allocates a new value from the IKEv2 Certificate 204 Encodings registry: 206 TBD Raw Public Key 208 6. Acknowledgements 210 This document reproduces some parts of the similar TLS document 211 ([RFC7250]). 213 7. References 215 7.1. Normative References 217 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 218 Requirement Levels", BCP 14, RFC 2119, March 1997. 220 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 221 Housley, R., and W. Polk, "Internet X.509 Public Key 222 Infrastructure Certificate and Certificate Revocation List 223 (CRL) Profile", RFC 5280, May 2008. 225 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 226 Kivinen, "Internet Key Exchange Protocol Version 2 227 (IKEv2)", STD 79, RFC 7296, October 2014. 229 [RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in 230 the Internet Key Exchange Version 2 (IKEv2)", RFC 7427, 231 DOI 10.17487/RFC7427, January 2015, 232 . 234 [RFC7619] Smyslov, V. and P. Wouters, "The NULL Authentication 235 Method in the Internet Key Exchange Protocol Version 2 236 (IKEv2)", RFC 7619, DOI 10.17487/RFC7619, August 2015, 237 . 239 7.2. Informative References 241 [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography 242 Standards (PKCS) #1: RSA Cryptography Specifications 243 Version 2.1", RFC 3447, DOI 10.17487/RFC3447, February 244 2003, . 246 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying 247 Material in DNS", RFC 4025, DOI 10.17487/RFC4025, March 248 2005, . 250 [RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional 251 Algorithms and Identifiers for RSA Cryptography for use in 252 the Internet X.509 Public Key Infrastructure Certificate 253 and Certificate Revocation List (CRL) Profile", RFC 4055, 254 DOI 10.17487/RFC4055, June 2005, 255 . 257 [RFC4754] Fu, D. and J. Solinas, "IKE and IKEv2 Authentication Using 258 the Elliptic Curve Digital Signature Algorithm (ECDSA)", 259 RFC 4754, DOI 10.17487/RFC4754, January 2007, 260 . 262 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 263 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 265 [RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk, 266 "Elliptic Curve Cryptography Subject Public Key 267 Information", RFC 5480, DOI 10.17487/RFC5480, March 2009, 268 . 270 [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, 271 "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 272 5996, DOI 10.17487/RFC5996, September 2010, 273 . 275 [RFC6394] Barnes, R., "Use Cases and Requirements for DNS-Based 276 Authentication of Named Entities (DANE)", RFC 6394, DOI 277 10.17487/RFC6394, October 2011, 278 . 280 [RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J., 281 Weiler, S., and T. Kivinen, "Using Raw Public Keys in 282 Transport Layer Security (TLS) and Datagram Transport 283 Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, 284 June 2014, . 286 [RSA] R. Rivest, ., A. Shamir, ., and . L. Adleman, "A Method 287 for Obtaining Digital Signatures and Public-Key 288 Cryptosystems", February 1978. 290 Appendix A. Examples 292 This appendix provides examples of the actual payloads sent on the 293 wire. 295 A.1. ECDSA Example 297 This first example uses the 256-bit ECDSA private/public key pair 298 defined in section 8.1 of the IKEv2 ECDSA document [RFC4754]. 300 The public key is as follows: 302 o Algorithm : id-ecPublicKey (1.2.840.10045.2.1) 304 o Fixed curve: secp256r1 (1.2.840.10045.3.1.7) 306 o Public key x coordinate : cb28e099 9b9c7715 fd0a80d8 e47a7707 307 9716cbbf 917dd72e 97566ea1 c066957c 309 o Public key y coordinate : 2b57c023 5fb74897 68d058ff 4911c20f 310 dbe71e36 99d91339 afbb903e e17255dc 312 The SubjectPublicKeyInfo ASN.1 object is as follows: 314 0000 : SEQUENCE 315 0002 : SEQUENCE 316 0004 : OBJECT IDENTIFIER id-ecPublicKey (1.2.840.10045.2.1) 317 000d : OBJECT IDENTIFIER secp256r1 (1.2.840.10045.3.1.7) 318 0017 : BIT STRING (66 bytes) 319 00000000: 0004 cb28 e099 9b9c 7715 fd0a 80d8 e47a 320 00000010: 7707 9716 cbbf 917d d72e 9756 6ea1 c066 321 00000020: 957c 2b57 c023 5fb7 4897 68d0 58ff 4911 322 00000030: c20f dbe7 1e36 99d9 1339 afbb 903e e172 323 00000040: 55dc 325 The first byte (00) of the bit string indicates that there is no 326 "number of unused bits", and the second byte (04) indicates 327 uncompressed form ([RFC5480]). Those two octets are followed by the 328 values of X and Y. 330 The final encoded SubjectPublicKeyInfo object is as follows: 332 00000000: 3059 3013 0607 2a86 48ce 3d02 0106 082a 333 00000010: 8648 ce3d 0301 0703 4200 04cb 28e0 999b 334 00000020: 9c77 15fd 0a80 d8e4 7a77 0797 16cb bf91 335 00000030: 7dd7 2e97 566e a1c0 6695 7c2b 57c0 235f 336 00000040: b748 9768 d058 ff49 11c2 0fdb e71e 3699 337 00000050: d913 39af bb90 3ee1 7255 dc 339 This will result in the final IKEv2 Certificate Payload: 341 00000000: NN00 0060 XX30 5930 1306 072a 8648 ce3d 342 00000010: 0201 0608 2a86 48ce 3d03 0107 0342 0004 343 00000020: cb28 e099 9b9c 7715 fd0a 80d8 e47a 7707 344 00000030: 9716 cbbf 917d d72e 9756 6ea1 c066 957c 345 00000040: 2b57 c023 5fb7 4897 68d0 58ff 4911 c20f 346 00000050: dbe7 1e36 99d9 1339 afbb 903e e172 55dc 348 Where NN is the next payload type (i.e., the type of the payload that 349 immediately follows this Certificate payload). 351 Note to the RFC editor / IANA, replace the XX above with the newly 352 allocated Raw Public Key number (in hex notation), and remove this 353 note. 355 A.2. RSA Example 357 This second example uses a random 1024-bit RSA key. 359 The public key is as follows: 361 o Algorithm : rsaEncryption (1.2.840.113549.1.1.1) 363 o Modulus n (1024 bits, decimal): 364 1323562071162740912417075551025599045700 365 3972512968992059076067098474693867078469 366 7654066339302927451756327389839253751712 367 9485277759962777278073526290329821841100 368 9721044682579432931952695408402169276996 369 5181887843758615443536914372816830537901 370 8976615344413864477626646564638249672329 371 04996914356093900776754835411 373 o Modulus n (1024 bits, hexadecimal): bc7b4347 49c7b386 00bfa84b 374 44f88187 9a2dda08 d1f0145a f5806c2a ed6a6172 ff0dc3d4 cd601638 375 e8ca348e bdca5742 31cadc97 12e209b1 fddba58a 8c62b369 038a3d1e 376 aa727c1f 39ae49ed 6ebc30f8 d9b52e23 385a4019 15858c59 be72f343 377 fb1eb87b 16ffc5ab 0f8f8fe9 f7cb3e66 3d8fe9f9 ecfa1230 66f36835 378 8ceaefd3 380 o Exponent e (17 bits, decimal): 65537 382 o Exponent e (17 bits, hexadecimal): 10001 384 The SubjectPublicKeyInfo ASN.1 object is as follows: 386 0000 : SEQUENCE 387 0003 : SEQUENCE 388 0005 : OBJECT IDENTIFIER rsaEncryption (1.2.840.113549.1.1.1) 389 0016 : NULL 390 0018 : BIT STRING (141 bytes) 391 00000000: 0030 8189 0281 8100 bc7b 4347 49c7 b386 392 00000010: 00bf a84b 44f8 8187 9a2d da08 d1f0 145a 393 00000020: f580 6c2a ed6a 6172 ff0d c3d4 cd60 1638 394 00000030: e8ca 348e bdca 5742 31ca dc97 12e2 09b1 395 00000040: fddb a58a 8c62 b369 038a 3d1e aa72 7c1f 396 00000050: 39ae 49ed 6ebc 30f8 d9b5 2e23 385a 4019 397 00000060: 1585 8c59 be72 f343 fb1e b87b 16ff c5ab 398 00000070: 0f8f 8fe9 f7cb 3e66 3d8f e9f9 ecfa 1230 399 00000080: 66f3 6835 8cea efd3 0203 0100 01 401 The first byte (00) of the bit string indicates that there is no 402 "number of unused bits". Inside that bit string there is an ASN.1 403 sequence having 2 integers. The second byte (30) indicates that this 404 is beginning of the sequence, and the next byte (81) indicates the 405 length does not fit in 7 bits, but requires one byte, so the length 406 is in the next byte (89). Then starts the first integer with tag 407 (02) and length (81 81). After that we have the modulus (prefixed 408 with 0 so it will not be a negative number). After the modulus there 409 follows the tag (02) and length (03) of the exponent, and the last 3 410 bytes are the exponent. 412 The final encoded SubjectPublicKeyInfo object is as follows: 414 00000000: 3081 9f30 0d06 092a 8648 86f7 0d01 0101 415 00000010: 0500 0381 8d00 3081 8902 8181 00bc 7b43 416 00000020: 4749 c7b3 8600 bfa8 4b44 f881 879a 2dda 417 00000030: 08d1 f014 5af5 806c 2aed 6a61 72ff 0dc3 418 00000040: d4cd 6016 38e8 ca34 8ebd ca57 4231 cadc 419 00000050: 9712 e209 b1fd dba5 8a8c 62b3 6903 8a3d 420 00000060: 1eaa 727c 1f39 ae49 ed6e bc30 f8d9 b52e 421 00000070: 2338 5a40 1915 858c 59be 72f3 43fb 1eb8 422 00000080: 7b16 ffc5 ab0f 8f8f e9f7 cb3e 663d 8fe9 423 00000090: f9ec fa12 3066 f368 358c eaef d302 0301 424 000000a0: 0001 426 This will result in the final IKEv2 Certificate Payload: 428 00000000: NN00 00a7 XX30 819f 300d 0609 2a86 4886 429 00000010: f70d 0101 0105 0003 818d 0030 8189 0281 430 00000020: 8100 bc7b 4347 49c7 b386 00bf a84b 44f8 431 00000030: 8187 9a2d da08 d1f0 145a f580 6c2a ed6a 432 00000040: 6172 ff0d c3d4 cd60 1638 e8ca 348e bdca 433 00000050: 5742 31ca dc97 12e2 09b1 fddb a58a 8c62 434 00000060: b369 038a 3d1e aa72 7c1f 39ae 49ed 6ebc 435 00000070: 30f8 d9b5 2e23 385a 4019 1585 8c59 be72 436 00000080: f343 fb1e b87b 16ff c5ab 0f8f 8fe9 f7cb 437 00000090: 3e66 3d8f e9f9 ecfa 1230 66f3 6835 8cea 438 000000a0: efd3 0203 0100 01 440 Where NN is the next payload type (i.e., the type of the payload that 441 immediately follows this Certificate payload). 443 Note to the RFC editor / IANA, replace the XX above with the newly 444 allocated Raw Public Key number, and remove this note. 446 Authors' Addresses 448 Tero Kivinen 449 INSIDE Secure 450 Eerikinkatu 28 451 HELSINKI FI-00180 452 FI 454 Email: kivinen@iki.fi 456 Paul Wouters 457 Red Hat 459 Email: pwouters@redhat.com 461 Hannes Tschofenig 463 Email: Hannes.Tschofenig@gmx.net 464 URI: http://www.tschofenig.priv.at