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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DHC Working Group S. Jiang 3 Internet-Draft Huawei Technologies Co., Ltd 4 Intended status: Standards Track L. Li 5 Expires: June 7, 2017 Y. Cui 6 Tsinghua University 7 T. Jinmei 8 Infoblox Inc. 9 T. Lemon 10 Nominum, Inc. 11 D. Zhang 12 December 4, 2016 14 Secure DHCPv6 15 draft-ietf-dhc-sedhcpv6-18 17 Abstract 19 DHCPv6 includes no deployable security mechanism that can protect 20 end-to-end communication between DHCP clients and servers. This 21 document describes a mechanism for using public key cryptography to 22 provide such security. The mechanism provides encryption in all 23 cases, and can be used for authentication based on pre-sharing of 24 authorized certificates. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on June 7, 2017. 43 Copyright Notice 45 Copyright (c) 2016 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 61 2. Requirements Language and Terminology . . . . . . . . . . . . 3 62 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 63 4. Security Issues of DHCPv6 . . . . . . . . . . . . . . . . . . 4 64 5. Secure DHCPv6 Overview . . . . . . . . . . . . . . . . . . . 5 65 5.1. Solution Overview . . . . . . . . . . . . . . . . . . . . 5 66 5.2. New Components . . . . . . . . . . . . . . . . . . . . . 6 67 5.3. Support for Algorithm Agility . . . . . . . . . . . . . . 7 68 5.4. Caused change to RFC3315 . . . . . . . . . . . . . . . . 7 69 5.5. Applicability . . . . . . . . . . . . . . . . . . . . . . 8 70 6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 8 71 7. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 11 72 8. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . 13 73 9. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 14 74 9.1. Increasing Number Check . . . . . . . . . . . . . . . . . 14 75 10. Extensions for Secure DHCPv6 . . . . . . . . . . . . . . . . 14 76 10.1. New DHCPv6 Options . . . . . . . . . . . . . . . . . . . 14 77 10.1.1. Algorithm Option . . . . . . . . . . . . . . . . . . 15 78 10.1.2. Certificate Option . . . . . . . . . . . . . . . . . 17 79 10.1.3. Signature option . . . . . . . . . . . . . . . . . . 18 80 10.1.4. Increasing-number Option . . . . . . . . . . . . . . 19 81 10.1.5. Encryption Key Tag Option . . . . . . . . . . . . . 19 82 10.1.6. Encrypted-message Option . . . . . . . . . . . . . . 20 83 10.2. New DHCPv6 Messages . . . . . . . . . . . . . . . . . . 21 84 10.3. Status Codes . . . . . . . . . . . . . . . . . . . . . . 21 85 11. Security Considerations . . . . . . . . . . . . . . . . . . . 22 86 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 87 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 88 14. Change log [RFC Editor: Please remove] . . . . . . . . . . . 24 89 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 27 90 15.1. Normative References . . . . . . . . . . . . . . . . . . 27 91 15.2. Informative References . . . . . . . . . . . . . . . . . 28 92 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29 94 1. Introduction 96 The Dynamic Host Configuration Protocol for IPv6 (DHCPv6, [RFC3315]) 97 allows DHCPv6 servers to flexibly provide addressing and other 98 configuration information relating to local network infrastructure to 99 DHCP clients. The protocol provides no deployable security 100 mechanism, and consequently is vulnerable to various attacks. 102 This document provides a brief summary of the security 103 vulnerabilities of the DHCPv6 protocol and then describes a new 104 extension to the protocol that provides two additional types of 105 security: 107 o authentication of the DHCPv6 client and the DHCPv6 server to 108 defend against active attacks, such as spoofing. 110 o encryption between the DHCPv6 client and the DHCPv6 server in 111 order to protect the DHCPv6 communication from pervasive 112 monitoring. 114 The extension specified in this document applies only to end-to-end 115 communication between DHCP servers and clients. Options added by 116 relay agents in Relay-Forward messages, and options other than the 117 client message in Relay-Reply messages sent by DHCP servers, are not 118 protected. Such communications are already protected using the 119 mechanism described in section 21.1 in [RFC3315]. 121 This extension introduces two new DHCPv6 messages: the Encrypted- 122 Query and the Encrypted-Response messages. It defines six new DHCPv6 123 options: the Algorithm, Certificate, Signature, Increasing-number, 124 Encryption Key Tag option and Encrypted-message options. The 125 Algorithm, Certificate, Signature, and Increasing-number options are 126 used for authentication. The Encryption-Query message, Encryption- 127 Response message, Encrypted-message option and Encryption Key Tag 128 option are used for encryption. 130 2. Requirements Language and Terminology 132 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 133 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 134 document are to be interpreted as described in [RFC2119] when they 135 appear in ALL CAPS. When these words are not in ALL CAPS (such as 136 "should" or "Should"), they have their usual English meanings, and 137 are not to be interpreted as [RFC2119] key words. 139 3. Terminology 141 This section defines terminology specific to secure DHCPv6 used in 142 this document. 144 secure DHCPv6 client: A node that initiates a DHCPv6 request on a 145 link to obtain DHCPv6 configuration parameters from 146 one or more DHCPv6 servers using the encryption and 147 optional authentication mechanisms defined in this 148 document. 150 secure DHCPv6 server: A DHCPv6 server that implements the 151 authentication and encryption mechanisms defined in 152 this document, and is configured to use them. 154 4. Security Issues of DHCPv6 156 [RFC3315] defines an authentication mechanism with integrity 157 protection. This mechanism uses a symmetric key that is shared by 158 the client and server for authentication. It does not provide any 159 key distribution mechanism. 161 For this approach, operators can set up a key database for both 162 servers and clients from which the client obtains a key before 163 running DHCPv6. However, manual key distribution runs counter to the 164 goal of minimizing the configuration data needed at each host. 165 Consequently, there are no known deployments of this security 166 mechanism. 168 [RFC3315] provides an additional mechanism for preventing off-network 169 timing attacks using the Reconfigure message: the Reconfigure Key 170 authentication method. However, this method protects only the 171 Reconfigure message. The key is transmitted in plaintext to the 172 client in earlier exchanges and so this method is vulnerable to on- 173 path active attacks. 175 Anonymity Profile for DHCP Clients [RFC7844] explains how to generate 176 DHCPv4 or DHCPv6 requests that minimize the disclosure of identifying 177 information. However, the anonymity profile limits the use of the 178 certain options. It also cannot anticipate new options that may 179 contain private information is defined. In addition, the anonymity 180 profile does not work in cases where the client wants to maintain 181 anonymity from eavesdroppers but must identify itself to the DHCP 182 server with which it intends to communicate. 184 Privacy consideration for DHCPv6 [RFC7824] presents an analysis of 185 the privacy issues associated with the use of DHCPv6 by Internet 186 users. No solutions are presented. 188 Current DHCPv6 messages are still transmitted in cleartext and the 189 privacy information within the DHCPv6 message is not protected from 190 passive attack, such as pervasive monitoring [RFC7258]. The privacy 191 information of the IPv6 host, such as DUID, may be gleaned to find 192 location information, previous visited networks and so on. [RFC7258] 193 claims that pervasive monitoring should be mitigated in the design of 194 IETF protocol, where possible. 196 To better address the problem of passive monitoring and to achieve 197 authentication without requiring a symmetric key distribution 198 solution for DHCP, this document defines an asymmetric key 199 authentication and encryption mechanism. This protects against both 200 active attacks, such as spoofing, and passive attacks, such as 201 pervasive monitoring. 203 5. Secure DHCPv6 Overview 205 5.1. Solution Overview 207 The following figure illustrates secure DHCPv6 procedure. Briefly, 208 this extension establishes the server's identity with an anonymous 209 Information-Request exchange. Once the server's identity has been 210 established, the client may either choose to communicate with the 211 server or not. Not communicating with an unknown server avoids 212 revealing private information, but if there is no known server on a 213 particular link, the client will be unable to communicate with a DHCP 214 server. 216 If the client chooses to communicate with the selected server(s), it 217 uses the Encrypted-Query message to encapsulate its communications to 218 the DHCP server. The server responds with Encrypted-Response 219 messages. Normal DHCP messages are encapsulated in these two new 220 messages using the new defined Encrypted-message option. Besides the 221 Encrypted-message option, the Signature option is defined to verify 222 the integrity of the DHCPv6 messages and then authentication of 223 client and server. The Increasing number option is defined to detect 224 replay attack. 226 +-------------+ +-------------+ 227 |DHCPv6 Client| |DHCPv6 Server| 228 +-------------+ +-------------+ 229 | Information-request | 230 |----------------------------------------->| 231 | Algorithm option | 232 | Option Request option | 233 | | 234 | Reply | 235 |<-----------------------------------------| 236 | Certificate option | 237 | Signature option | 238 | Increasing-number option | 239 | Server Identifier option | 240 | | 241 | Encryption-Query | 242 |----------------------------------------->| 243 | Encrypted-message option | 244 | Server Identifier option | 245 | Encryption Key Tag option | 246 | | 247 | Encryption-Response | 248 |<-----------------------------------------| 249 | Encrypted-message option | 250 | | 252 Figure 1: Secure DHCPv6 Procedure 254 5.2. New Components 256 The new components of the mechanism specified in this document are as 257 follows: 259 o Servers and clients that use certificates first generate a public/ 260 private key pair and then obtain a certificate that signs the 261 public key. The Certificate option is defined to carry the 262 certificate of the sender. 264 o The algorithm option is defined to carry the algorithms lists for 265 algorithm agility. 267 o The signature is generated using the private key to verify the 268 integrity of the DHCPv6 messages. The Signature option is defined 269 to carry the signature. 271 o The increasing number is used to detect replayed packet. The 272 Timestamp is one of the possible implementation choices. The 273 Increasing-number option is defined to carry a strictly-increasing 274 serial number. 276 o The encryption key Tag is calculated from the public key data. 277 The Encryption Key Tag option is defined to identify the used 278 public/private key pair. 280 o The Encrypted-message option is defined to contain the encrypted 281 DHCPv6 message. 283 o The Encrypted-Query message is sent from the secure DHCPv6 client 284 to the secure DHCPv6 server. The Encrypted-Query message MUST 285 contain the Encrypted-message option. In addition, the Server 286 Identifier option MUST be contained if it is contained in the 287 original DHCPv6 message. The Encrypted-Query message MUST NOT 288 contain other options except the above options. 290 o The Encrypted-Response message is sent from the secure DHCPv6 291 server to the secure DHCPv6 client. The Encrypted-Response 292 message MUST contain the Encrypted-message option. The Encrypted- 293 Response message MUST NOT contain any other options except it. 295 5.3. Support for Algorithm Agility 297 In order to provide a means of addressing problems that may emerge 298 with existing hash algorithms, signature algorithm and encryption 299 algorithms in the future, this document provides a mechanism to 300 support algorithm agility. The support for algorithm agility in this 301 document is mainly a algorithm notification mechanism between the 302 client and the server. The same client and server SHOULD use the 303 same algorithm in a single communication session. The sender can 304 offer a set of algorithms, and then the receiver selects one 305 algorithm for the future communication. 307 5.4. Caused change to RFC3315 309 For secure DHCPv6, the Solicit and Rebind messages can be sent only 310 to the selected server(s) which share one common certificate. If the 311 client doesn't like the received Advertise(s) it could restart the 312 whole process and selects another certificate, but it will be more 313 expensive, and there's no guarantee that other servers can provide 314 better Advertise(s). 316 [RFC3315] provides an additional mechanism for preventing off-network 317 timing attacks using the Reconfigure message: the Reconfigure Key 318 authentication method. Secure DHCPv6 can protect the Reconfigure 319 message using the encryption method. So the Reconfigure Key 320 authentication method SHOULD NOT be used if Secure DHCPv6 is applied. 322 5.5. Applicability 324 In principle, secure DHCPv6 is applicable in any environment where 325 physical security on the link is not assured and attacks on DHCPv6 326 are a concern. In practice, however, authenticated and encrypted 327 DHCPv6 configuration will rely on some operational assumptions mainly 328 regarding public key distribution and management. In order to 329 achieve the more wide use of secure DHCPv6, opportunistic security 330 [RFC7435] can be applied to secure DHCPv6 deployment, which allows 331 DHCPv6 encryption in environments where support for authentication is 332 not available. 334 Secure DHCPv6 can achieve authentication and encryption based on pre- 335 sharing of authorized certificates. The One feasible environment in 336 an early deployment stage would be enterprise networks. In 337 enterprise networks, the client is manually pre-configured with the 338 trusted servers' public key and the server is also manually pre- 339 configured with the trusted clients' public keys. In some scenario, 340 such as coffee shop where the certificate cannot be validated and 341 don't want to be blocked from the Internet, then the DHCPv6 342 configuration process can be encrypted without authentication. 344 Note that this deployment scenario based on manual operation is not 345 different very much from the existing, shared-secret based 346 authentication mechanisms defined in [RFC3315] in terms of 347 operational costs. However, Secure DHCPv6 is still securer than the 348 shared-secret mechanism in that even if clients' keys stored for the 349 server are stolen that does not mean an immediate threat as these are 350 public keys. In addition, if some kind of PKI is used with Secure 351 DHCPv6, even if the initial installation of the certificates is done 352 manually, it will help reduce operational costs of revocation in case 353 a private key (especially that of the server) is compromised. 355 6. DHCPv6 Client Behavior 357 The secure DHCPv6 client is pre-configured with a certificate and its 358 corresponding private key for client authentication. If the client 359 does not obtain a certificate from CA, it can generate the self- 360 signed certificate. 362 The secure DHCPv6 client sends Information-request message as per 363 [RFC3315]. The Information-request message is used by the DHCPv6 364 client to request the server's certificate information without having 365 addresses, prefixes or any non-security options assigned to it. The 366 contained Option Request option MUST carry the option code of the 367 Certificate option. In addition, the contained Algorithm option MUST 368 be constructed as explained in Section 10.1.1. The Information- 369 request message MUST NOT include any other DHCPv6 options except the 370 above options to minimize client's privacy information leakage. 372 When receiving the Reply messages from DHCPv6 servers, a secure 373 DHCPv6 client discards any DHCPv6 message that meets any of the 374 following conditions: 376 o the Signature option is missing, 378 o multiple Signature options are present, 380 o the Certificate option is missing. 382 And then the client first checks acknowledged hash, signature and 383 encryption algorithms that the server supports. If the hash 384 algorithm field is zero, then it indicates that the hash algorithm is 385 fixed according to the corresponding signature algorithm. The client 386 also uses the acknowledged algorithms in the return messages. 388 Then the client checks the authority of the server. The client 389 validates the certificates through the pre-configured local trusted 390 certificates list or other methods. A certificate that finds a match 391 in the local trust certificates list is treated as verified. At this 392 point, the client has either recognized the certificate of the 393 server, or decided to drop the message. 395 The client MUST now authenticate the server by verifying the 396 signature and checking increasing number, if there is a Increasing- 397 number option. The order of two procedures is left as an 398 implementation decision. It is RECOMMENDED to check increasing 399 number first, because signature verification is much more 400 computationally expensive. The client checks the Increasing-number 401 option according to the rule defined in Section 9.1 if it is 402 contained. For the message without an Increasing-number option, 403 according to the client's local policy, it MAY be acceptable or 404 rejected. The Signature field verification MUST show that the 405 signature has been calculated as specified in Section 10.1.3. Only 406 the messages that get through both the signature verification and 407 increasing number check (if there is a Increasing-number option) are 408 accepted. Reply message that does not pass the above tests MUST be 409 discarded. 411 If there are multiple authenticated DHCPv6 certs, the client selects 412 one DHCPv6 cert for the following communication. The selected 413 certificate may correspond to multiple DHCPv6 servers. If there are 414 no authenticated DHCPv6 certs or existing servers fail 415 authentication, the client should retry a number of times. The 416 client conducts the server discovery process as per section 18.1.5 of 418 [RFC3315] to avoid the packet storm. In this way, it is difficult 419 for the rogue server to beat out a busy "real" server. And then the 420 client takes some alternative action depending on its local policy, 421 such as attempting to use an unsecured DHCPv6 server. 423 Once the server has been authenticated, the DHCPv6 client sends the 424 Encrypted-Query message to the DHCPv6 server. The Encrypted-Query 425 message contains the Encrypted-message option, which MUST be 426 constructed as explained in Section 10.1.6. The Encrypted-message 427 option contains the encrypted DHCPv6 message using the public key 428 contained in the selected cert. In addition, the Server Identifier 429 option MUST be included if it is in the original message (i.e. 430 Request, Renew, Decline, Release) to avoid the need for other servers 431 receiving the message to attempt to decrypt it. The Encrypted-Query 432 message MUST include the Encryption Key Tag option to identify the 433 used public/private key pair, which is constructed as explained in 434 Section 10.1.5. The Encrypted-Query message MUST NOT contain any 435 other DHCPv6 option except the Server Identifier option, Encryption 436 Key Tag option, Encrypted-Message option. 438 The first DHCPv6 message sent from the client to the server, such as 439 Solicit message, MUST contain the Certificate option, Signature 440 option and Increasing-number option for client authentication. The 441 encryption text SHOULD be formatted as explain in [RFC5652]. The 442 Certificate option MUST be constructed as explained in 443 Section 10.1.2. In addition, one and only one Signature option MUST 444 be contained, which MUST be constructed as explained in 445 Section 10.1.3. One and only one Increasing-number option SHOULD be 446 contained, which MUST be constructed as explained in Section 10.1.4. 447 In addition, the subsequent encrypted DHCPv6 message can also contain 448 the Increasing-number option to defend against replay attack. 450 For the received Encrypted-Response message, the client MUST drop the 451 Encrypted-Response message if other DHCPv6 option except Encrypted- 452 message option is contained. Then, the client extracts the 453 Encrypted-message option and decrypts it using its private key to 454 obtain the original DHCPv6 message. In this document, it is assumed 455 that the client uses only one certificate for the encrypted DHCPv6 456 configuration. So, the corresponding private key is used for 457 decryption. After the decryption, it handles the message as per 458 [RFC3315]. If the decrypted DHCPv6 message contains the Increasing- 459 number option, the DHCPv6 client checks it according to the rule 460 defined in Section 9.1. 462 If the client fails to get the proper parameters from the chosen 463 server(s), it can select another authenticated certificate and send 464 the Encrypted-Query message to another authenticated server(s) for 465 parameters configuration until the client obtains the proper 466 parameters. 468 When the decrypted message is Reply message with an error status 469 code, the error status code indicates the failure reason on the 470 server side. According to the received status code, the client MAY 471 take follow-up action: 473 o Upon receiving an AuthenticationFail error status code, the client 474 is not able to build up the secure communication with the server. 475 However, there may be other DHCPv6 servers available that 476 successfully complete authentication. The client MAY use the 477 AuthenticationFail as a hint and switch to other DHCPv6 server if 478 it has another one. The client SHOULD retry with another 479 authenticated certificate. However, if the client decides to 480 retransmit using the same certificate after receiving 481 AuthenticationFail, it MUST NOT retransmit immediately and MUST 482 follow normal retransmission routines defined in [RFC3315]. 484 o Upon receiving a DecryptionFail error status code, the client MAY 485 resend the message following normal retransmission routines 486 defined in [RFC3315]. 488 o Upon receiving a ReplayDetected error status code, the client MAY 489 resend the message with an adjusted Increasing-number option 490 according to the returned number from the DHCPv6 server. 492 o Upon receiving a SignatureFail error status code, the client MAY 493 resend the message following normal retransmission routines 494 defined in [RFC3315]. 496 7. DHCPv6 Server Behavior 498 The secure DHCPv6 server is pre-configured with a certificate and its 499 corresponding private key for server authentication. If the server 500 does not obtain the certificate from CA, it can generate the self- 501 signed certificate. 503 When the DHCPv6 server receives the Information-request message and 504 the contained Option Request option identifies the request is for the 505 server's certificate information, it SHOULD first check the hash, 506 signature, encryption algorithms sets that the client supports. The 507 server selects one hash, signature, encryption algorithm from the 508 acknowledged algorithms sets for the future communication. If the 509 hash algorithm is fixed according to the signature algorithm, then 510 the hash algorithm field is set to zero. And then, the server 511 replies with a Reply message to the client. The Reply message MUST 512 contain the requested Certificate option, which MUST be constructed 513 as explained in Section 10.1.2, and Server Identifier option. In 514 addition, the Reply message MUST contain one and only one Signature 515 option, which MUST be constructed as explained in Section 10.1.3. 516 Besides, the Reply message SHOULD contain one and only one 517 Increasing-number option, which MUST be constructed as explained in 518 Section 10.1.4. 520 Upon the receipt of Encrypted-Query message, the server MUST drop the 521 message if the other DHCPv6 option is contained except Server 522 Identifier option, Encryption Key Tag option, Encrypted-message 523 option. Then, the server checks the Server Identifier option if it 524 is contained. The DHCPv6 server drops the message that is not for 525 it, thus not paying cost to decrypt messages. If it is the target 526 server, according to the Encryption Key Tag option, the server 527 identifies the used public/private key pair and decrypts the 528 Encrypted-message option using the corresponding private key. If the 529 server does not find the corresponding private key, then it tries all 530 the private keys and establishes the relationship between the 531 encryption key tag and the private key. If the decryption fails, the 532 server discards the received message. 534 If secure DHCPv6 server needs client authentication and decrypted 535 message is a Solicit/Information-request message which contains the 536 information for client authentication, the secure DHCPv6 server 537 discards the received message that meets any of the following 538 conditions: 540 o the Signature option is missing, 542 o multiple Signature options are present, 544 o the Certificate option is missing. 546 For the signature failure, the server SHOULD send an encrypted Reply 547 message with an UnspecFail (value 1, [RFC3315]) error status code to 548 the client. 550 The server validates the client's certificate through the local pre- 551 configured trusted certificates list. A certificate that finds a 552 match in the local trust certificates list is treated as verified. 553 The message that fails authentication validation MUST be dropped. In 554 such failure, the DHCPv6 server replies with an encrypted Reply 555 message with an AuthenticationFail error status code, defined in 556 Section 10.3, back to the client. At this point, the server has 557 either recognized the authentication of the client, or decided to 558 drop the message. 560 If the decrypted message contains the Increasing-number option, the 561 server checks it according to the rule defined in Section 9.1. If 562 the check fails, an encrypted Reply message with a ReplayDetected 563 error status code, defined in Section 10.3, should be sent back to 564 the client. In addition, a Increasing-number option is carried to 565 indicate the server's stored number for the client to use. According 566 to the server's local policy, the message without an Increasing- 567 number option MAY be acceptable or rejected. 569 The Signature field verification MUST show that the signature has 570 been calculated as specified in Section 10.1.3. If the signature 571 check fails, the DHCPv6 server SHOULD send an encrypted Reply message 572 with a SignatureFail error status code. Only the clients that get 573 through both the signature verification and increasing number check 574 (if there is a Increasing-number option) are accepted as 575 authenticated clients and continue to be handled their message as 576 defined in [RFC3315]. 578 Once the client has been authenticated, the DHCPv6 server sends the 579 Encrypted-response message to the DHCPv6 client. The Encrypted- 580 response message MUST only contain the Encrypted-message option, 581 which MUST be constructed as explained in Section 10.1.6. The 582 encryption text SHOULD be formatted as explain in [RFC5652]. The 583 Encrypted-message option contains the encrypted DHCPv6 message that 584 is encrypted using the authenticated client's public key. To provide 585 the replay protection, the Increasing-number option can be contained 586 in the encrypted DHCPv6 message. 588 8. Relay Agent Behavior 590 When a DHCPv6 relay agent receives an Encrypted-query or Encrypted- 591 response message, it may not recognize this message. The unknown 592 messages MUST be forwarded as described in [RFC7283]. 594 When a DHCPv6 relay agent recognizes the Encrypted-query and 595 Encrypted-response messages, it forwards the message according to 596 section 20 of [RFC3315]. There is nothing more the relay agents have 597 to do, it neither needs to verify the messages from client or server, 598 nor add any secure DHCPv6 options. Actually, by definition in this 599 document, relay agents MUST NOT add any secure DHCPv6 options. 601 Relay-forward and Relay-reply messages MUST NOT contain any 602 additional Certificate option or Increasing-number option, aside from 603 those present in the innermost encapsulated messages from the client 604 or server. 606 Relay agent is RECOMMENDED to cache server announcements to form the 607 list of the available DHCPv6 server certs. If the relay agent 608 receives the Information-request message, then it replies with a list 609 of server certs available locally. In this way, the client can be 610 confident of a quick response, and therefore treat the lack of a 611 quick response as an indication that no authenticated DHCP servers 612 exist. 614 9. Processing Rules 616 9.1. Increasing Number Check 618 In order to check the Increasing-number option, defined in 619 Section 10.1.4, the client/server has one stable stored number for 620 replay attack detection. The server should keep a record of the 621 increasing number forever. And the client keeps a record of the 622 increasing number during the DHCPv6 configuration process with the 623 DHCPv6 server. And the client can forget the increasing number 624 information after the transaction is finished. 626 It is essential to remember that the increasing number is finite. 627 All arithmetic dealing with sequence numbers must be performed modulo 628 2^64. This unsigned arithmetic preserves the relationship of 629 sequence numbers as they cycle from 2^64 - 1 to 0 again. 631 In order to check the Increasing-number option, the following 632 comparison is needed. 634 NUM.STO = the stored number in the client/server 636 NUM.REC = the acknowledged number from the received message 638 The Increasing-number option in the received message passes the 639 increasing number check if NUM.REC is more than NUM.STO. And then, 640 the value of NUM.STO is changed into the value of NUM.REC. 642 The increasing number check fails if NUM.REC is equal with or less 643 than NUM.STO 645 10. Extensions for Secure DHCPv6 647 This section describes the extensions to DHCPv6. Six new DHCPv6 648 options, two new DHCPv6 messages and six new status codes are 649 defined. 651 10.1. New DHCPv6 Options 652 10.1.1. Algorithm Option 654 The Algorithm option carries the algorithms sets for algorithm 655 agility, which is sent from the client to server. 657 0 1 2 3 658 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 1 659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 660 | OPTION_SIGNATURE | option-len | 661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 662 . EA-id List . 663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 664 . SA-id List . 665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 666 . HA-id List . 667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 669 Figure 2: Algorithm Option 671 o option-code: OPTION_SIGNATURE (TBA1). 673 o option-len: length of EA-id List + length of SA-id List + length 674 of HA-id List in octets. 676 o EA-id: The format of the EA-id List field is shown in Figure 3. 678 0 1 2 3 679 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 1 680 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 681 | EA-num | EA-id | 682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 683 . ... . 684 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 685 | EA-id | 686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 688 EA-num The number of the following EA-ids. 690 EA-id Encryption Algorithm id. The encryption algorithm 691 is used for the encrypted DHCPv6 configuration 692 process. This design is adopted in order to provide 693 encryption algorithm agility. The value is from the 694 Encryption Algorithm for Secure DHCPv6 registry in 695 IANA. A registry of the initial assigned values 696 is defined in Section 12. The mandatory encryption 697 algorithms MUST be included. 699 Figure 3: EA-id List Field 701 o SA-id List: The format of the SA-id List field is shown in 702 Figure 4. 704 0 1 2 3 705 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 1 706 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 707 | SA-num | SA-id | 708 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 709 . ... . 710 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 711 | SA-id | 712 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 714 SA-num The number of the following SA-ids. 716 SA-id Signature Algorithm id. This design is adopted in 717 order to provide signature algorithm agility. The 718 value is from the Signature Algorithm for Secure 719 DHCPv6 registry in IANA. The support of RSASSA-PKCS1-v1_5 720 is mandatory. A registry of the initial assigned 721 values is defined in Section 12. The mandatory 722 signature algorithms MUST be included. 724 Figure 4: SA-id List Field 726 o HA-id List: The format of the HA-id List field is shown in 727 Figure 5. 729 0 1 2 3 730 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 1 731 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 732 | HA-num | HA-id | 733 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 734 . ... . 735 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 736 | HA-id | 737 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 739 HA-num The number of the following HA-ids. 741 HA-id Hash Algorithm id. This design is adopted in order to 742 provide hash algorithm agility. The value is from the 743 Hash Algorithm for Secure DHCPv6 registry in IANA. The 744 support of SHA-256 is mandatory. A registry of the 745 initial assigned values is defined in Section 12. 746 The mandatory hash algorithms MUST be included. 748 Figure 5: HA-id List Field 750 10.1.2. Certificate Option 752 The Certificate option carries the certificate of the client/server. 753 The format of the Certificate option is described as follows: 755 0 1 2 3 756 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 1 757 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 758 | OPTION_CERTIFICATE | option-len | 759 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 760 | EA-id | SA-id | 761 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 762 | | 763 . Certificate . 764 | | 765 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 767 Figure 6: Certificate Option 769 o option-code: OPTION_CERTIFICATE (TBA2). 771 o option-len: 4 + length of Certificate in octets. 773 o EA-id: Encryption Algorithm id. The encryption algorithm is used 774 for the encrypted DHCPv6 configuration process. This design is 775 adopted in order to provide encryption algorithm agility. The 776 value is from the Encryption Algorithm for Secure DHCPv6 registry 777 in IANA. A registry of the initial assigned values is defined in 778 Section 12. If the value of EA-id is 0, then the certificate is 779 not used for encryption. 781 o SA-id: Signature Algorithm id. The signature algorithm is used 782 for computing the signature result. The value is from the 783 Signature Algorithm for Secure DHCPv6 registry in IANA. A 784 registry of the initial assigned values is defined in Section 12. 785 If the value of SA-id is 0, then the certificate is not used for 786 signature check. 788 o Certificate: A variable-length field containing certificates. The 789 encoding of certificate and certificate data MUST be in format as 790 defined in Section 3.6, [RFC7296]. The support of X.509 791 certificate is mandatory. 793 It should be noticed that the scenario where the values of EA-id and 794 SA-id are all 0, it makes no sense and MUST NOT be used. 796 10.1.3. Signature option 798 The Signature option allows a signature that is signed by the private 799 key to be attached to a DHCPv6 message. The Signature option could 800 be in any place within the DHCPv6 message while it is logically 801 created after the entire DHCPv6 header and options. It protects the 802 entire DHCPv6 header and options, including itself. The format of 803 the Signature option is described as follows: 805 0 1 2 3 806 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 1 807 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 808 | OPTION_SIGNATURE | option-len | 809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 810 | SA-id | HA-id | 811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 812 | | 813 . Signature (variable length) . 814 . . 815 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 817 Figure 7: Signature Option 819 o option-code: OPTION_SIGNATURE (TBA3). 821 o option-len: 4 + length of Signature field in octets. 823 o SA-id: Signature Algorithm id. The signature algorithm is used 824 for computing the signature result. This design is adopted in 825 order to provide signature algorithm agility. The value is from 826 the Signature Algorithm for Secure DHCPv6 registry in IANA. The 827 support of RSASSA-PKCS1-v1_5 is mandatory. A registry of the 828 initial assigned values is defined in Section 12. 830 o HA-id: Hash Algorithm id. The hash algorithm is used for 831 computing the signature result. This design is adopted in order 832 to provide hash algorithm agility. The value is from the Hash 833 Algorithm for Secure DHCPv6 registry in IANA. The support of 834 SHA-256 is mandatory. A registry of the initial assigned values 835 is defined in Section 12. If the hash algorithm is fixed 836 according to the corresponding signature algorithm, the HA-id 837 field is set to zero. 839 o Signature: A variable-length field containing a digital signature. 840 The signature value is computed with the hash algorithm and the 841 signature algorithm, as described in HA-id and SA-id. The 842 Signature field MUST be padded, with all 0, to the next octet 843 boundary if its size is not a multiple of 8 bits. The padding 844 length depends on the signature algorithm, which is indicated in 845 the SA-id field. 847 Note: If Secure DHCPv6 is used, the DHCPv6 message is encrypted in a 848 way that the authentication mechanism defined in RFC3315 does not 849 understand. So the Authentication option SHOULD NOT be used if 850 Secure DHCPv6 is applied. 852 10.1.4. Increasing-number Option 854 The Increasing-number option carries the strictly increasing number 855 for anti-replay protection. It is optional. 857 0 1 2 3 858 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 1 859 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 860 | OPTION_INCREASING_NUM | option-len | 861 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 862 | | 863 | InreasingNum (64-bit) | 864 | | 865 | | 866 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 868 option-code OPTION_INCREASING_NUM (TBA4). 870 option-len 8, in octets. 872 IncreasingNum A strictly increasing number for the replay attack detection 873 which is more than the local stored number. 875 Figure 8: Increasing-number Option 877 10.1.5. Encryption Key Tag Option 879 The Encryption Key Tag option carries the key identifier which is 880 calculated from the public key data. The Encrypted-Query message 881 MUST contain the Encryption Key Tag option to identify the used 882 public/private key pair. 884 0 1 2 3 885 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 1 886 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 887 | option-code | option-len | 888 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 889 | | 890 . encryption key tag . 891 . (variable) . 892 . . 893 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 895 Figure 9: Encryption Key Tag Option 897 option-code OPTION_ENCRY_KT (TBA5). 899 option-len Length of the encryption key tag. 901 encryption key tag A variable length field containing the encryption 902 key tag sent from the client to server to identify the used 903 public/private key pair. The encryption key tag is calculated 904 from the public key data, like fingerprint of a specific public 905 key. 907 10.1.6. Encrypted-message Option 909 The Encrypted-message option carries the encrypted DHCPv6 message, 910 which is calculated with the recipient's public key. 912 The format of the Encrypted-message option is: 914 0 1 2 3 915 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 1 916 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 917 | option-code | option-len | 918 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 919 | | 920 . encrypted DHCPv6 message . 921 . (variable) . 922 . . 923 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 925 Figure 10: Encrypted-message Option 927 option-code OPTION_ENCRYPTED_MSG (TBA6). 929 option-len Length of the encrypted DHCPv6 message. 931 encrypted DHCPv6 message A variable length field containing the 932 encrypted DHCPv6 message. In Encrypted-Query message, it contains 933 encrypted DHCPv6 message sent from a client to server. In 934 Encrypted-response message, it contains encrypted DHCPv6 message 935 sent from a server to client. 937 10.2. New DHCPv6 Messages 939 Two new DHCPv6 messages are defined to achieve the DHCPv6 encryption: 940 Encrypted-Query and Encrypted-Response. Both the DHCPv6 messages 941 defined in this document share the following format: 943 0 1 2 3 944 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 1 945 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 946 | msg-type | transaction-id | 947 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 948 | | 949 . options . 950 . (variable) . 951 | | 952 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 954 Figure 11: The format of Encrypted-Query and Encrypted-Response 955 Messages 957 msg-type Identifier of the message type. It can be either 958 Encrypted-Query (TBA7) or DHCPv6-Response (TBA8). 960 transaction-id The transaction ID for this message exchange. 962 options The Encrypted-Query message MUST contain the 963 Encrypted-message option, Encryption Key Tag option 964 and Server Identifier option if the message in the 965 Encrypted-message option has a Server Identifier 966 option. The Encrypted-Response message MUST only 967 contain the Encrypted-message option. 969 10.3. Status Codes 971 The following new status codes, see Section 5.4 of [RFC3315] are 972 defined. 974 o AuthenticationFail (TBD9): indicates that the message from the 975 DHCPv6 client fails authentication check. 977 o ReplayDetected (TBD10): indicates the message from DHCPv6 client 978 fails the increasing number check. 980 o SignatureFail (TBD11): indicates the message from DHCPv6 client 981 fails the signature check. 983 11. Security Considerations 985 This document provides the authentication and encryption mechanisms 986 for DHCPv6. 988 [RFC6273] has analyzed possible threats to the hash algorithms used 989 in SEND. Since Secure DHCPv6 defined in this document uses the same 990 hash algorithms in similar way to SEND, analysis results could be 991 applied as well: current attacks on hash functions do not constitute 992 any practical threat to the digital signatures used in the signature 993 algorithm in Secure DHCPv6. 995 A server, whose local policy accepts messages without a Increasing- 996 number option, may have to face the risk of replay attacks. 998 There are some mandatory algorithm for encryption algorithm in this 999 document. It may be at some point that the mandatory algorithm is no 1000 longer safe to use. 1002 If the client tries more than one cert for client authentication, the 1003 server can easily get a client that implements this to enumerate its 1004 entire cert list and probably learn a lot about a client that way. 1006 12. IANA Considerations 1008 This document defines six new DHCPv6 [RFC3315] options. The IANA is 1009 requested to assign values for these six options from the DHCPv6 1010 Option Codes table of the DHCPv6 Parameters registry maintained in 1011 http://www.iana.org/assignments/dhcpv6-parameters. The six options 1012 are: 1014 The Algorithm Option (TBA1), described in Section 10.1.2. 1016 The Certificate Option (TBA2), described in Section 10.1.2. 1018 The Signature Option (TBA3), described in Section 10.1.3. 1020 The Increasing-number Option (TBA4),described in Section 10.1.4. 1022 The Encryption Key Tag Option (TBA5),described in Section 10.1.5. 1024 The Encrypted-message Option (TBA6), described in Section 10.1.6. 1026 The IANA is also requested to assign value for these two messages 1027 from the DHCPv6 Message Types table of the DHCPv6 Parameters registry 1028 maintained in http://www.iana.org/assignments/dhcpv6-parameters. The 1029 two messages are: 1031 The Encrypted-Query Message (TBA7), described in Section 10.2. 1033 The Encrypted-Response Message (TBA8), described in Section 10.2. 1035 The IANA is also requested to add three new registry tables to the 1036 DHCPv6 Parameters registry maintained in 1037 http://www.iana.org/assignments/dhcpv6-parameters. The three tables 1038 are the Hash Algorithm for Secure DHCPv6 table, the Signature 1039 Algorithm for Secure DHCPv6 table and the Encryption Algorithm for 1040 Secure DHCPv6 table. 1042 Initial values for these registries are given below. Future 1043 assignments are to be made through Standards Action [RFC5226]. 1044 Assignments for each registry consist of a name, a value and a RFC 1045 number where the registry is defined. 1047 Hash Algorithm for Secure DHCPv6. The values in this table are 8-bit 1048 unsigned integers. The following initial values are assigned for 1049 Hash Algorithm for Secure DHCPv6 in this document: 1051 Name | Value | RFCs 1052 -------------------+---------+-------------- 1053 SigAlg-Combined | ox00 | this document 1054 SHA-256 | 0x01 | this document 1055 SHA-512 | 0x02 | this document 1057 Signature Algorithm for Secure DHCPv6. The values in this table are 1058 8-bit unsigned integers. The following initial values are assigned 1059 for Signature Algorithm for Secure DHCPv6 in this document: 1061 Name | Value | RFCs 1062 -------------------+---------+-------------- 1063 Non-SigAlg | 0x00 | this document 1064 RSASSA-PKCS1-v1_5 | 0x01 | this document 1066 Encryption algorithm for Secure DHCPv6. The values in this table are 1067 8-bit unsigned integers. The following initial values are assigned 1068 for encryption algorithm for Secure DHCPv6 in this document: 1070 Name | Value | RFCs 1071 -------------------+---------+-------------- 1072 Non-EncryAlg | 0x00 | this document 1073 RSA | 0x01 | this document 1075 IANA is requested to assign the following new DHCPv6 Status Codes, 1076 defined in Section 10.3, in the DHCPv6 Parameters registry maintained 1077 in http://www.iana.org/assignments/dhcpv6-parameters: 1079 Code | Name | Reference 1080 ---------+-----------------------+-------------- 1081 TBD9 | AuthenticationFail | this document 1082 TBD10 | ReplayDetected | this document 1083 TBD11 | SignatureFail | this document 1085 13. Acknowledgements 1087 The authors would like to thank Tomek Mrugalski, Bernie Volz, 1088 Jianping Wu, Randy Bush, Yiu Lee, Sean Shen, Ralph Droms, Jari Arkko, 1089 Sean Turner, Stephen Farrell, Christian Huitema, Stephen Kent, Thomas 1090 Huth, David Schumacher, Francis Dupont, Gang Chen, Suresh Krishnan, 1091 Fred Templin, Robert Elz, Nico Williams, Erik Kline, Alan DeKok, 1092 Bernard Aboba, Sam Hartman, Zilong Liu and other members of the IETF 1093 DHC working group for their valuable comments. 1095 This document was produced using the xml2rfc tool [RFC2629]. 1097 14. Change log [RFC Editor: Please remove] 1099 draft-ietf-dhc-sedhcpv6-18: Add the Algorithm option. The algorithm 1100 option contains the EA-id List, SA-id List, HA-id List, and then the 1101 certificate and signature options do not contain the algorithm list; 1102 Add the Encryption Key Tag option to identify the used public/private 1103 key pair; Delete the AlgorithmNotSupported error status code; Delete 1104 some description on that secure DHCPv6 exchanges the server selection 1105 method; Delete the DecryptionFail error status code; For the case 1106 where the client's certificate is missed, then the server discards 1107 the received message. Add the assumption that: For DHCPv6 client, 1108 just one certificate is used for the DHCPv6 configuration. Add the 1109 statement that: For the first Encrypted-Query message, the server 1110 needs to try all the possible private keys and then records the 1111 relationship between the public key and the encryption key tag. 1113 draft-ietf-dhc-sedhcpv6-17: Change the format of the certificate 1114 option according to the comments from Bernie. 1116 draft-ietf-dhc-sedhcpv6-16: For the algorithm agility part, the 1117 provider can offer multiple EA-id, SA-id, HA-id and then receiver 1118 choose one from the algorithm set. 1120 draft-ietf-dhc-sedhcpv6-15: Increasing number option only contains 1121 the strictly increasing number; Add some description about why 1122 encryption is needed in Security Issues of DHCPv6 part; 1123 draft-ietf-dhc-sedhcpv6-14: For the deployment part, Tofu is out of 1124 scope and take Opportunistic security into consideration; Increasing 1125 number option is changed into 64 bits; Increasing number check is a 1126 separate section; IncreasingnumFail error status code is changed into 1127 ReplayDetected error status code; Add the section of "caused change 1128 to RFC3315"; 1130 draft-ietf-dhc-sedhcpv6-13: Change the Timestamp option into 1131 Increasing-number option and the corresponding check method; Delete 1132 the OCSP stampling part for the certificate check; Add the scenario 1133 where the hash and signature algorithms cannot be separated; Add the 1134 comparison with RFC7824 and RFC7844; Add the encryption text format 1135 and reference of RFC5652. Add the consideration of scenario where 1136 multiple DHCPv6 servers share one common DHCPv6 server. Add the 1137 statement that Encrypted-Query and Encrypted-Response messages can 1138 only contain certain options: Server Identifier option and Encrypted- 1139 message option. Add opportunistic security for deployment 1140 consideration. Besides authentication+encyrption mode, encryption- 1141 only mode is added. 1143 draft-ietf-dhc-sedhcpv6-12: Add the Signature option and timestamp 1144 option during server/client authentication process. Add the hash 1145 function and signature algorithm. Add the requirement: The 1146 Information-request message cannot contain any other options except 1147 ORO option. Modify the use of "SHOULD"; Delete the reference of 1148 RFC5280 and modify the method of client/server cert verification; Add 1149 the relay agent cache function for the quick response when there is 1150 no authenticated server. 2016-4-24. 1152 draft-ietf-dhc-sedhcpv6-11: Delete the Signature option, because the 1153 encrypted DHCPv6 message and the Information-request message (only 1154 contain the Certificate option) don't need the Signature option for 1155 message integrity check; Rewrite the "Applicability" section; Add the 1156 encryption algorithm negotiation process; To support the encryption 1157 algorithm negotiation, the Certificate option contains the EA- 1158 id(encryption algorithm identifier) field; Reserve the Timestamp 1159 option to defend against the replay attacks for encrypted DHCPv6 1160 configuration process; Modify the client behavior when there is no 1161 authenticated DHCPv6 server; Add the DecryptionFail error code. 1162 2016-3-9. 1164 draft-ietf-dhc-sedhcpv6-10: merge DHCPv6 authentication and DHCPv6 1165 encryption. The public key option is removed, because the device can 1166 generate the self-signed certificate if it is pre-configured the 1167 public key not the certificate. 2015-12-10. 1169 draft-ietf-dhc-sedhcpv6-09: change some texts about the deployment 1170 part.2015-12-10. 1172 draft-ietf-dhc-sedhcpv6-08: clarified what the client and the server 1173 should do if it receives a message using unsupported algorithm; 1174 refined the error code treatment regarding to AuthenticationFail and 1175 TimestampFail; added consideration on how to reduce the DoS attack 1176 when using TOFU; other general editorial cleanups. 2015-06-10. 1178 draft-ietf-dhc-sedhcpv6-07: removed the deployment consideration 1179 section; instead, described more straightforward use cases with TOFU 1180 in the overview section, and clarified how the public keys would be 1181 stored at the recipient when TOFU is used. The overview section also 1182 clarified the integration of PKI or other similar infrastructure is 1183 an open issue. 2015-03-23. 1185 draft-ietf-dhc-sedhcpv6-06: remove the limitation that only clients 1186 use PKI- certificates and only servers use public keys. The new text 1187 would allow clients use public keys and servers use PKI-certificates. 1188 2015-02-18. 1190 draft-ietf-dhc-sedhcpv6-05: addressed comments from mail list that 1191 responsed to the second WGLC. 2014-12-08. 1193 draft-ietf-dhc-sedhcpv6-04: addressed comments from mail list. 1194 Making timestamp an independent and optional option. Reduce the 1195 serverside authentication to base on only client's certificate. 1196 Reduce the clientside authentication to only Leaf of Faith base on 1197 server's public key. 2014-09-26. 1199 draft-ietf-dhc-sedhcpv6-03: addressed comments from WGLC. Added a 1200 new section "Deployment Consideration". Corrected the Public Key 1201 Field in the Public Key Option. Added consideration for large DHCPv6 1202 message transmission. Added TimestampFail error code. Refined the 1203 retransmission rules on clients. 2014-06-18. 1205 draft-ietf-dhc-sedhcpv6-02: addressed comments (applicability 1206 statement, redesign the error codes and their logic) from IETF89 DHC 1207 WG meeting and volunteer reviewers. 2014-04-14. 1209 draft-ietf-dhc-sedhcpv6-01: addressed comments from IETF88 DHC WG 1210 meeting. Moved Dacheng Zhang from acknowledgement to be co-author. 1211 2014-02-14. 1213 draft-ietf-dhc-sedhcpv6-00: adopted by DHC WG. 2013-11-19. 1215 draft-jiang-dhc-sedhcpv6-02: removed protection between relay agent 1216 and server due to complexity, following the comments from Ted Lemon, 1217 Bernie Volz. 2013-10-16. 1219 draft-jiang-dhc-sedhcpv6-01: update according to review comments from 1220 Ted Lemon, Bernie Volz, Ralph Droms. Separated Public Key/ 1221 Certificate option into two options. Refined many detailed 1222 processes. 2013-10-08. 1224 draft-jiang-dhc-sedhcpv6-00: original version, this draft is a 1225 replacement of draft-ietf-dhc-secure-dhcpv6, which reached IESG and 1226 dead because of consideration regarding to CGA. The authors followed 1227 the suggestion from IESG making a general public key based mechanism. 1228 2013-06-29. 1230 15. References 1232 15.1. Normative References 1234 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1235 Requirement Levels", BCP 14, RFC 2119, 1236 DOI 10.17487/RFC2119, March 1997, 1237 . 1239 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1240 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 1241 December 1998, . 1243 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 1244 C., and M. Carney, "Dynamic Host Configuration Protocol 1245 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 1246 2003, . 1248 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1249 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1250 DOI 10.17487/RFC3971, March 2005, 1251 . 1253 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1254 Control Message Protocol (ICMPv6) for the Internet 1255 Protocol Version 6 (IPv6) Specification", RFC 4443, 1256 DOI 10.17487/RFC4443, March 2006, 1257 . 1259 [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, 1260 RFC 5652, DOI 10.17487/RFC5652, September 2009, 1261 . 1263 [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, 1264 "Network Time Protocol Version 4: Protocol and Algorithms 1265 Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, 1266 . 1268 [RFC7283] Cui, Y., Sun, Q., and T. Lemon, "Handling Unknown DHCPv6 1269 Messages", RFC 7283, DOI 10.17487/RFC7283, July 2014, 1270 . 1272 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1273 Kivinen, "Internet Key Exchange Protocol Version 2 1274 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1275 2014, . 1277 [RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection 1278 Most of the Time", RFC 7435, DOI 10.17487/RFC7435, 1279 December 2014, . 1281 [RFC7824] Krishnan, S., Mrugalski, T., and S. Jiang, "Privacy 1282 Considerations for DHCPv6", RFC 7824, 1283 DOI 10.17487/RFC7824, May 2016, 1284 . 1286 [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity 1287 Profiles for DHCP Clients", RFC 7844, 1288 DOI 10.17487/RFC7844, May 2016, 1289 . 1291 15.2. Informative References 1293 [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, 1294 DOI 10.17487/RFC2629, June 1999, 1295 . 1297 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1298 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1299 DOI 10.17487/RFC5226, May 2008, 1300 . 1302 [RFC6273] Kukec, A., Krishnan, S., and S. Jiang, "The Secure 1303 Neighbor Discovery (SEND) Hash Threat Analysis", RFC 6273, 1304 DOI 10.17487/RFC6273, June 2011, 1305 . 1307 [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an 1308 Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May 1309 2014, . 1311 [RSA] RSA Laboratories, "RSA Encryption Standard, Version 2.1, 1312 PKCS 1", November 2002. 1314 Authors' Addresses 1316 Sheng Jiang 1317 Huawei Technologies Co., Ltd 1318 Q14, Huawei Campus, No.156 Beiqing Road 1319 Hai-Dian District, Beijing, 100095 1320 CN 1322 Email: jiangsheng@huawei.com 1324 Lishan Li 1325 Tsinghua University 1326 Beijing 100084 1327 P.R.China 1329 Phone: +86-15201441862 1330 Email: lilishan48@gmail.com 1332 Yong Cui 1333 Tsinghua University 1334 Beijing 100084 1335 P.R.China 1337 Phone: +86-10-6260-3059 1338 Email: yong@csnet1.cs.tsinghua.edu.cn 1340 Tatuya Jinmei 1341 Infoblox Inc. 1342 3111 Coronado Drive 1343 Santa Clara, CA 1344 US 1346 Email: jinmei@wide.ad.jp 1348 Ted Lemon 1349 Nominum, Inc. 1350 2000 Seaport Blvd 1351 Redwood City, CA 94063 1352 USA 1354 Phone: +1-650-381-6000 1355 Email: Ted.Lemon@nominum.com 1356 Dacheng Zhang 1357 Beijing 1358 CN 1360 Email: dacheng.zhang@gmail.com