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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: However, the CA certificates for each key, and the contents published by each key MUST be equivalent. In other words it MUST not make a difference which of the keys is used as a starting point for top-down validation by RP software. -- The document date (July 8, 2019) is 1753 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 5781 ** Obsolete normative reference: RFC 6486 (Obsoleted by RFC 9286) ** Obsolete normative reference: RFC 7230 (Obsoleted by RFC 9110, RFC 9112) Summary: 4 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group T. Bruijnzeels 3 Internet-Draft NLnet Labs 4 Intended status: Standards Track C. Martinez 5 Expires: January 9, 2020 LACNIC 6 R. Austein 7 Dragon Research Labs 8 July 8, 2019 10 RPKI Signed Object for Trust Anchor Keys 11 draft-ietf-sidrops-signed-tal-03 13 Abstract 15 Trust Anchor Locators (TALs) [I-D.ietf-sidrops-https-tal] are used by 16 Relying Parties in the RPKI to locate and validate Trust Anchor 17 certificates used in RPKI validation. This document defines an RPKI 18 signed object for Trust Anchor Keys (TAK), that can be used by Trust 19 Anchors to signal their set of current keys and the location(s) of 20 the accompanying CA certiifcates to Relying Parties, as well as 21 changes to this set in the form of revoked keys and new keys, in 22 order to support both planned and unplanned key rolls without 23 impacting RPKI validation. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on January 9, 2020. 42 Copyright Notice 44 Copyright (c) 2019 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Requirements notation . . . . . . . . . . . . . . . . . . . . 2 60 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 3. TAK Object definition . . . . . . . . . . . . . . . . . . . . 4 62 3.1. The TAK Object Content Type . . . . . . . . . . . . . . . 4 63 3.2. The TAK Object eContent . . . . . . . . . . . . . . . . . 4 64 3.2.1. version . . . . . . . . . . . . . . . . . . . . . . . 5 65 3.2.2. current . . . . . . . . . . . . . . . . . . . . . . . 5 66 3.2.3. revoked . . . . . . . . . . . . . . . . . . . . . . . 6 67 3.3. TAK Object Validation . . . . . . . . . . . . . . . . . . 6 68 4. TAK Object Generation and Publication . . . . . . . . . . . . 6 69 5. Relying Party Use . . . . . . . . . . . . . . . . . . . . . . 7 70 6. Maintaining multiple TA keys . . . . . . . . . . . . . . . . 8 71 7. Performing TA Key Rolls . . . . . . . . . . . . . . . . . . . 10 72 7.1. Phase 1: Add a TAK for Key 'A' . . . . . . . . . . . . . 10 73 7.2. Phase 2: Add a Key 'B' . . . . . . . . . . . . . . . . . 10 74 7.3. Phase 3: Roll to Key 'C' . . . . . . . . . . . . . . . . 11 75 7.3.1. Planned Direction Roll . . . . . . . . . . . . . . . 11 76 7.3.2. Unplanned Direction Roll . . . . . . . . . . . . . . 11 77 7.4. Phase X: Roll to Key 'D', 'E', .. . . . . . . . . . . . . 12 78 8. Deployment Considerations . . . . . . . . . . . . . . . . . . 12 79 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 80 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 81 10.1. OID . . . . . . . . . . . . . . . . . . . . . . . . . . 13 82 10.2. File Extension . . . . . . . . . . . . . . . . . . . . . 13 83 11. Security Considerations . . . . . . . . . . . . . . . . . . . 13 84 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 85 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 86 13.1. Normative References . . . . . . . . . . . . . . . . . . 13 87 13.2. Informative References . . . . . . . . . . . . . . . . . 15 88 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 90 1. Requirements notation 92 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 93 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 94 "OPTIONAL" in this document are to be interpreted as described in BCP 95 14 [RFC2119] [RFC8174] when, and only when, they appear in all 96 capitals, as shown here. 98 2. Overview 100 Trust Anchor Locators (TALs) [I-D.ietf-sidrops-https-tal] are used by 101 Relying Parties in the RPKI to locate and validate Trust Anchor (TA) 102 certificates used in RPKI validation. However, until now there has 103 been no formal way of notifying Relying Parties (RP) of updates to a 104 TAL. Such updates may be needed in particular in case a Trust Anchor 105 needs to perform a planned, or unplanned, key roll. 107 This document defines a new RPKI signed object that can be used to 108 document the current set of keys and the location(s) of the 109 accompanying CA certificates, as well as any changes to this set. 110 This allows RPs to be notified automatically of such changes, and 111 enables Trust Anchors to pre-stage a number of operational keys so 112 that planned and unplanned key rolls can be performed without risking 113 the invalidation of the RPKI tree under the TA. We call this object 114 the Trust Anchor Keys (TAK) object. 116 When Relying Parties (RPs) are first bootstrapped, they use any 117 current TAL to discover a key and location(s) of the TA 118 certificate(s) for a TA. The RP can then retrieve and validating the 119 TA certificate, and subsequently validate the manifest [RFC6486] and 120 CRL [section 5 of @!RFC6487]. However, before processing any other 121 objects it will then first validate the TAK object, if present. All 122 enumerated new keys (and locations) are then added to a new list of 123 current TA keys for this TA. The RP will then recursively fetch and 124 validate the TA certificates, manifest, CRL and TAK objects for each 125 of these keys. As a part of this process the RP will also compile a 126 list of revoked keys enumerated by any of the validly signed TAK 127 objects. As the final step the RP will then filter out any revoked 128 TA keys from its new set. This new set now replaces the previous 129 set. 131 This process allows Trust Anchors to operate a set of N current keys, 132 where any key can effectively revoke any or all of the other keys to 133 perform either a planned, or an unplanned, key roll. This also 134 allows Trust Anchors to produce long lived TAK objects as forward 135 pointers to RPs, and retire its old key when doing a key roll. While 136 the generic process is quite involved, the amount of work needed to 137 support an envisioned normal key roll is fairly limited. Under 138 normal circumstances a TA will typically have two current keys, so 139 that is can perform an emergency roll over in case one of the keys is 140 lost. This means that the RP will need to validate one additional CA 141 certificate, a CRL, a manifest and two TAK objects. 143 When a key roll is executed a TA will remove one old key, and 144 introduce one new (back-up) key. The RP will remove the old key from 145 its set, and it will not be queried again, and it will add the new 146 key and its TA certifcate location(s). 148 Only in a situation where an RP is very outdated can it be expected 149 that the RP will have to discover several chained TAK object. But, 150 since it will remove the outdated TALs in this process, this presents 151 a one time cost only. 153 3. TAK Object definition 155 The TAK object makes use of the template for RPKI digitally signed 156 objects [RFC6488], which defines a Crytopgraphic Message Syntax (CMS) 157 [RFC5652] wrapper for the Signed TALs content as well as a generic 158 validation procedure for RPKI signed objects. Therefore, to complete 159 the specification of the TAK object (see Section 4 of [RFC6488]), 160 this document defines: 162 o The OID defined in Section 3.1 that identifies the signed object 163 as being a TAK. (This OID appears within the eContentType in the 164 encapContentInfo object as well as the content-type signed 165 attribute in the signerInfo object). 167 o The ASN.1 syntax for the TAK eContent defined in Section 3.2. 169 o Additional steps to the validation steps specified in [RFC6488] 170 required to validate the TAK, defined in Section 3.3. 172 3.1. The TAK Object Content Type 174 This document requests an OID for TAK objects as follows: 176 signed-Tal OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) 177 rsadsi(113549) pkcs(1) pkcs9(9) 16 id-smime (1) TBD } 179 This OID MUST appear both within the eContentType in the 180 encapContentInfo object as well as the content-type signed attribute 181 in the signerInfo object (see [RFC6488]) 183 3.2. The TAK Object eContent 185 The content of a TAK object is ASN.1 encoded using the Distinguished 186 Encoding Rules (DER) [X.690], and is defined as follows: 188 TAK ::= SEQUENCE { 189 version INTEGER DEFAULT 0, 190 current ::= SEQUENCE SIZE (1..MAX) OF CurrentKey, 191 revoked ::= SEQUENCE OF SubjectPublicKeyInfo 192 } 194 CurrentKey ::= SEQUENCE { 195 certificateURIs SEQUENCE SIZE (1..MAX) OF CertificateURI, 196 subjectPublicKeyInfo SubjectPublicKeyInfo 197 } 199 CertificateURI ::= IA5String 201 SubjectPublicKeyInfo ::= SEQUENCE { 202 algorithm AlgorithmIdentifier, 203 subjectPublicKey BIT STRING 204 } 206 3.2.1. version 208 The version number of the TAK object MUST be 0. 210 3.2.2. current 212 This field defines the set of current keys (CurrentKey) according to 213 the signer of this Signed TALs object. 215 3.2.2.1. CurrentKey 217 This field defines a current TA Key, equivalent to [I-D.ietf-sidrops- 218 https-tal]. This structure contains a sequence of one or more URIs 219 and a SubjectPublicKeyInfo. 221 3.2.2.1.1. certificateURIs 223 This field is equivalent to the URI section in section 2.1 of 224 [I-D.ietf-sidrops-https-tal]. It MUST contain at least one 225 CertificateURI element. Each CertificateURI element contains the 226 IA5String representation of either an rsync URI [RFC5781], or an 227 HTTPS URI [RFC7230]. 229 3.2.2.1.2. subjectPublicKeyInfo 231 This field contains a SubjectPublicKeyInfo [section 4.1.2.7 or 232 @!RFC5280] in DER format [X.690]. 234 3.2.3. revoked 236 This field contains the list of keys, identified by 237 SubjectPublicKeyInfo, that are no longer to be used according to the 238 signer of this document. 240 3.3. TAK Object Validation 242 To determine whether a TAK object is valid, the RP MUST perform the 243 following steps in addition to those specified in [RFC6488]: 245 o The eContentType OID matches the OID described in Section 3.1 247 o The TAK object appears as the product of a Trust Anchor CA 248 certificate. 250 o This Trust Anchor CA has published only one TAK object in its 251 repository for this key, and this object appears on the Manifest 252 as the only entry using the ".tak" extension (see [RFC6481]). In 253 case more than one TAK object is found, all such objects MUST be 254 considered invalid. 256 o The EE certificate of this TAK object describes its Internet 257 Number Resources (INRs) using the "inherit" attribute 259 o The decoded TAK content conforms to the format defined in 260 Section 3.2. 262 If the above procedure indicates that the manifest is invalid, then 263 the TAK object MUST be discarded and treated as though no TAK object 264 were present. 266 4. TAK Object Generation and Publication 268 A TA MAY choose to use TAK objects to communicate its set of current, 269 and revoked keys. If a TA chooses to use TAK objects, then it SHOULD 270 generate and publish TAK objects under each of its current keys. An 271 exception to this rule exists when a TA has lost permanent access to 272 one of its keys or the accompanying repository publication point. In 273 such cases however, the key in question MUST be revoked as described 274 below in Section 7. 276 A non-normative guideline for naming this object is that the filename 277 chosen for the Signed TAL Object in the publication repository be a 278 value derived from the public key part of the entity's key pair, 279 using the algorithm described for CRLs in section 2.2 of [RFC6481] 280 for generation of filenames. The filename extension of ".tak" MUST 281 be used to denote the object as a TAK. Note that this is in-line 282 with filename extensions defined in section 7.2 of [RFC6481] 284 In order to generate the TAK Objects, the TA MUST perform the 285 following actions: 287 o The TA MUST generate a key pair for a "one-time-use" EE 288 certificate to use for the TAK 290 o The TA MUST generate a one-time-use EE certificate for the TAK 292 o This EE certificate MUST have an SIA extension access description 293 field with an accessMethod OID value of id-ad-signedobject, where 294 the associated accessLocation references the publication point of 295 the TAK as an object URL. 297 o As described in [RFC6487], an [RFC3779] extension is required in 298 the EE certificate used for this object. However, because the 299 resource set is irrelevant to this object type, this certificate 300 MUST describe its Internet Number Resources (INRs) using the 301 "inherit" attribute, rather than explicit description of a 302 resource set. 304 o This EE certificate MUST have a "notBefore" time that matches, or 305 predates the moment that the TAK will be published. 307 o This EE certificate MUST have a "notAfter" time that reflects the 308 intended duration for which this TAK will be published. If the EE 309 certificate for a Signed TAL is expired, it MUST no longer be 310 published, but it MAY be replaced by a newly generated TAK object 311 with equivalent content and an updated "notAfter" time. 313 o The same set of current keys (see Section 3.2.2) MUST be included 314 on each TAK object for each current key. 316 o The TAK object MUST include all revoked keys (see Section 3.2.3) 317 that became revoked while the key signing the TAK in question was 318 current. 320 5. Relying Party Use 322 Relying Parties MUST keep a record of all current keys for each 323 configured Trust Anchor, as well as the URI(s) where the CA 324 certificate for each of these keys may be retrieved. This record MAY 325 be bootstrapped by the use of a pre-configured (and unsigned) TAL 326 file [I-D.ietf-sidrops-https-tal], but it MUST be updated with 327 authoritative signed information found in valid TAK objects found in 328 subsequent validation runs. 330 When performing top-down validation RPs MUST first validate and 331 process any TAK objects for each of its known current keys for a TA 332 by performing the following steps: 334 o A CA certificate is retrieved and validated from the known URIs as 335 described in sections 3 and 4 of [I-D.ietf-sidrops-https-tal]. 337 o The manifest and CRL for this certificate are then validated first 338 as described in [RFC6487] and [RFC6486]. 340 o The TAK file, if present, is validated as described in 341 Section 3.3. 343 For each valid TAK file thus found all current keys, i.e. 344 SubjectPublicKeyInfo and URIs, are kept. If any previously unknown 345 keys are added to the set of current keys, then they MUST also be 346 processed as described above. 348 Once the TAK objects for all keys are processed the set of current 349 keys and URIs for the TA is updated as follows: * All new current 350 keys found on any valid TAK object are added to the set of current 351 keys. * The set of URIs for each current key is replaced by the 352 union of all URIs for this key found on all valid TAK objects. * 353 Finally, any current key that matches any revoked key on any valid 354 TAK object is removed from the set of current keys. 356 Note that if a current key does not occur on any valid TAK object, 357 but it is not revoked either, then it and any previously known URIs 358 for it are kept. Also note that if an RP was bootstrapped using a 359 TAL file [I-D.ietf-sidrops-https-tal], the keys and URIs will now 360 have been replaced by values found on TAK objects. 362 After this the RP can choose any one of the valid CA certificates for 363 any key that is still in the set of current keys for this TA, in 364 order to continue the top-down validation of object for this TA as 365 described in [RFC6487]. 367 6. Maintaining multiple TA keys 369 If a TA operates multiple keys, then the signed material for these 370 keys MUST be published under different directories in the context of 371 the 'id-ad-caRepository' and 'id-ad-rpkiManifest' Subject Information 372 Access descriptions contained on the CA certificates [RFC6487]. 373 Publishing objects under the same space would lead to confusion at 374 best, and in case of file name collisions of objects invalidity. 376 However, the CA certificates for each key, and the contents published 377 by each key MUST be equivalent. In other words it MUST not make a 378 difference which of the keys is used as a starting point for top-down 379 validation by RP software. 381 This means that the IP and AS resources contained on all current CA 382 certificates for the current TA keys MUST be the same. Furthermore 383 for any delegation of IP and AS resources to a child, the TA MUST 384 have an equivalent CA certificate published under each of its keys. 385 Any updates in delegations MUST be reflected under each of its keys. 386 A TA SHOULD NOT publish any other objects besides a CRL, a Manifest, 387 a single TAK object, and any number of CA certificates for delegation 388 to child Certification Authorities. 390 If a TA uses a single remote publication server for its keys using 391 the RPKI publication protocol [RFC8181], then it MUST include all 392 and PDUs for the products of each of its keys 393 in a single query in order to ensure that they will reflect the same 394 content at all times. 396 If a TA uses multiple publication servers then it is by definition 397 inevitable that the content of different keys will be out of sync at 398 times. In such cases the TA SHOULD ensure that the duration of these 399 moments are limited to the shortest possible time. Furthermore the 400 following should be observed: 402 o In cases where a CA certificate is revoked completely, or replaced 403 by a certificate with a reduced set of resources, these changes 404 will not take effect fully until all the TA keys repository 405 publication points have been updated. Given that TA key 406 operations are normally performed infrequently we don't expect 407 that this is a problem. I.e. if the revocation or shrinking of an 408 issued CA certificate is staged for days, or weeks anyway, then 409 experiencing a delay of several minutes for the repository 410 publication points to all be updated is fairly insignificant. 412 o In cases where a CA certificate is replaced by a certificate with 413 an extend set of resources the TA MUST inform the receiving CA 414 only after all its repository publication points have been 415 updated. This ensures that the receiving CA will not issue any 416 products that could be invalid if an RP uses a TA key just before 417 the CA certificate was due to be updated. 419 Finally, note that the publication locations of CA certificates for 420 delegations to child CAs under each key will be different, and 421 therefore the Authority Information Access 'id-ad-caIssuers' value on 422 certificates issued by the child CAs may not match (section 4.8.7 of 423 [RFC6487]). However, this information is not considered critical for 424 validation of these objects and provided as hints to RP software 425 only. Therefore RP software MUST NOT reject these certificates based 426 on a mismatch of this value. 428 7. Performing TA Key Rolls 430 In this section we will describe how present day RPKI TAs that use 431 only one key pair, and that do not use TAK objects, can change to 432 having two current keys at all times allowing them to perform both 433 planned and unplanned key rolls. 435 7.1. Phase 1: Add a TAK for Key 'A' 437 Before adding any new keys a Trust Anchor may want to build up 438 operational experience in maintaining a TAK object that describes its 439 current key only. We will call refer to this key as key 'A' 440 throughout this section. 442 The TA will have a TAL file [I-D.ietf-sidrops-https-tal] that 443 contains one or more URIs where the (equivalent) CA certificates for 444 this key 'A' can be retrieved. The TA can now generate a TAK objects 445 that includes key 'A' only in its sequence of 'CurrentKey' values. 447 The TA SHOULD publish the CA certificate for key 'A' at one or more 448 new locations not used in the TAL file, and use these new URIs in the 449 TAK object. The TA is free to choose any naming strategy for these 450 locations. As a non-normative suggestion, one such approach could be 451 to use the date that this phase was started as part of the file name 452 or a directory where the CA certificate is published. 454 The TA can now monitor the retrieval of its CA certificates from the 455 URI(s) in the newly published TAK object, relative to the retrieval 456 from the URI(s) listed in its TAL file, to learn the proportion of 457 RPs that can successfully validate and use the TAK object. 459 7.2. Phase 2: Add a Key 'B' 461 The TA can now generate a new key pair, key 'B'. This key MUST now 462 be used to create a new CA certificate for this key, and issue 463 equivalent CA certificates for delegations to child CAs, as described 464 in Section 6. 466 At this point, the TA can also issue a new TAL file 467 [I-D.ietf-sidrops-https-tal] for key 'B', and test locally that the 468 validation outcome for the new key is indeed equivalent to the other 469 current key(s). 471 When the TA is certain that both keys are equivalent, it MUST issue a 472 new TAK object under each of its current keys, and include both the 473 old key 'A' and this new key 'B' in the set of current keys. 475 The TA SHOULD now also release a new TAL file for this new key 'B' as 476 the intended new key to be used by RP software. However, as 477 described above, it SHOULD use a different set of URIs in the TAL 478 compared to the TAK file, so that it can learn the proportion of RPs 479 that can successfully validate and use the updated TAK objects. 481 7.3. Phase 3: Roll to Key 'C' 483 In this phase a new key, key 'C' is generated as described above in 484 Section 7.2. And one of the previous keys is revoked. 486 7.3.1. Planned Direction Roll 488 If the key roll is planned, and the TA has access to all its keys 489 'A', 'B' and 'C', and the publication servers for each of the keys, 490 then a new TAK object is generated for each of these keys listing 491 keys 'B' and 'C' as current, and key 'A' as revoked. 493 The TA SHOULD now publish a long-lived TAK file, CRL and Manifest 494 under key 'A', remove all other content, and destroy key 'A'. This 495 way RP software that uses a TAL for key 'A' can still successfully 496 find keys 'B' and 'C', and in future 'D', 'E', etc. 498 If access to key 'A' was lost, then the process is slightly 499 different. The TAK object for key 'A' cannot be updated and will 500 therefore still refer to keys 'A' and 'B' as the current keys, and 501 include no revocations. However, an updated TAK object listing keys 502 'B' and 'C' as current, and listing key 'A' as revoked can still be 503 issued and published under keys 'B' and 'C'. As described in 504 Section 5 RPs will then discover that key 'A' is revoked, and 505 continue to use keys 'B' and 'C'. 507 7.3.2. Unplanned Direction Roll 509 If key 'B' is compromised, the process is similar to above, except of 510 course that now keys 'A' and 'C' are included in the set of current 511 keys, and key 'B' is in the set of revoked keys. If the TA still has 512 access to key 'B', then it SHOULD publish a long-lived TAK file, CRL 513 and manifest for key 'B' and remove all other content for it. If it 514 cannot perform this action then simply marking key 'B' as revoked 515 will still notify RPs to disregard it. 517 7.4. Phase X: Roll to Key 'D', 'E', .. 519 Further key rolls are essentially no different the roll to key 'C' 520 described in Section 7.3, except that there is no need to still 521 include key 'A' in the list of revoked keys when the the roll to key 522 'D' is performed. RPs will already have learned to that key 'A' is 523 revoked, before they learn about key 'D'. 525 8. Deployment Considerations 527 Including Signed TAL objects while RP tools do not support this 528 standard will result in these RPs rejecting these objects. It is not 529 expected that this will result in the invalidation of any other 530 object under a Trust Anchor. 532 That said, the flagging mechanism introduced here can only be relied 533 on once a majority of RPs support it. Defining when that moment 534 arrives is by definition something that cannot be established at the 535 time of writing this document. The use of unique URIs in TAK objects 536 compared to their equivalent TAL files should help operators 537 understand which proportion of RPs support this mechanism. 539 9. Security Considerations 541 It should be noted that because any key can revoke the other key(s), 542 a risk introduced: if an adversary can gain access to one of the 543 keys, and publication servers for it, then they can essentially take 544 over a TA. It should also be noted that a TA can revoke all of its 545 keys by accident and make itself obsolete. 547 However, these risks can be mitigated greatly by the use of Hardware 548 Security Modules (HSM) by TAs, which will guard against theft of a 549 private key, and operational processes to guard against (accidental) 550 mis-use of the keys in an HSM by operators. 552 Although HSMs can help against key theft, the risk of key loss is 553 still very applicable. In some ways more so, because back-ups are 554 hard by design. Key loss can easily happen for example when an 555 operator card set that is used to authorise use of a key in an HSM 556 can no longer be used, e.g. because cards are broken or lost, or a 557 persons who holds a card is sadly no longer with us, or passwords are 558 forgotten, etc. 560 In such cases the ability to perform an unplanned roll as described 561 in this document will be very useful, provided that access to the 562 both keys is arranged differently, and the issues affecting one key, 563 do not necessarily affect the other key. 565 An example where the planned rolls are useful is when a TA is using 566 an HSM from vendor X, and they want to migrate to an HSM from vendor 567 Y. 569 10. IANA Considerations 571 10.1. OID 573 IANA is to add the following to the "RPKI Signed Objects" registry: 575 Decimal | Description | References 576 --------+--------------------------------+--------------- 577 TBD | Trust Anchor Keys | [section 3.1] 579 10.2. File Extension 581 IANA is to add an item for the Signed TAL file extension to the "RPKI 582 Repository Name Scheme" created by [RFC6481] as follows: 584 Extension | RPKI Object | References 585 -----------+------------------------------------------- 586 .tak | Trust Anchor Keys | [this document] 588 11. Security Considerations 590 TBD 592 12. Acknowledgements 594 The authors wish to thank Martin Hoffmann for a thourough review of 595 this document. 597 13. References 599 13.1. Normative References 601 [I-D.ietf-sidrops-https-tal] 602 Huston, G., Weiler, S., Michaelson, G., Kent, S., and T. 603 Bruijnzeels, "Resource Public Key Infrastructure (RPKI) 604 Trust Anchor Locator", draft-ietf-sidrops-https-tal-08 605 (work in progress), April 2019. 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 [RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP 613 Addresses and AS Identifiers", RFC 3779, 614 DOI 10.17487/RFC3779, June 2004, 615 . 617 [RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI 618 Scheme", RFC 5781, DOI 10.17487/RFC5781, February 2010, 619 . 621 [RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for 622 Resource Certificate Repository Structure", RFC 6481, 623 DOI 10.17487/RFC6481, February 2012, 624 . 626 [RFC6486] Austein, R., Huston, G., Kent, S., and M. Lepinski, 627 "Manifests for the Resource Public Key Infrastructure 628 (RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012, 629 . 631 [RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for 632 X.509 PKIX Resource Certificates", RFC 6487, 633 DOI 10.17487/RFC6487, February 2012, 634 . 636 [RFC6488] Lepinski, M., Chi, A., and S. Kent, "Signed Object 637 Template for the Resource Public Key Infrastructure 638 (RPKI)", RFC 6488, DOI 10.17487/RFC6488, February 2012, 639 . 641 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 642 Protocol (HTTP/1.1): Message Syntax and Routing", 643 RFC 7230, DOI 10.17487/RFC7230, June 2014, 644 . 646 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 647 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 648 May 2017, . 650 [RFC8181] Weiler, S., Sonalker, A., and R. Austein, "A Publication 651 Protocol for the Resource Public Key Infrastructure 652 (RPKI)", RFC 8181, DOI 10.17487/RFC8181, July 2017, 653 . 655 [X.690] ITU-T Recommendation X.690 (2002) | ISO/IEC 8825-1:2002, 656 "Information technology - ASN.1 encoding rules: 657 Specification of Basic Encoding Rules (BER), Canonical 658 Encoding Rules (CER) and Distinguished Encoding Rules 659 (DER)", 2002. 661 13.2. Informative References 663 [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, 664 RFC 5652, DOI 10.17487/RFC5652, September 2009, 665 . 667 Authors' Addresses 669 Tim Bruijnzeels 670 NLnet Labs 672 Email: tim@nlnetlabs.nl 673 URI: https://www.nlnetlabs.nl/ 675 Carlos Martinez 676 LACNIC 678 Email: carlos@lacnic.net 679 URI: https://www.lacnic.net/ 681 Rob Austein 682 Dragon Research Labs 684 Email: sra@hactrn.net