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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force D. Wessels 3 Internet-Draft P. Barber 4 Intended status: Standards Track Verisign 5 Expires: April 18, 2021 M. Weinberg 6 Amazon 7 W. Kumari 8 Google 9 W. Hardaker 10 USC/ISI 11 October 15, 2020 13 Message Digest for DNS Zones 14 draft-ietf-dnsop-dns-zone-digest-14 16 Abstract 18 This document describes a protocol and new DNS Resource Record that 19 provides a cryptographic message digest over DNS zone data at rest. 20 The ZONEMD Resource Record conveys the digest data in the zone 21 itself. When used in combination with DNSSEC, ZONEMD allows 22 recipients to verify the zone contents for data integrity and origin 23 authenticity. This provides assurance that received zone data 24 matches published data, regardless of how the zone data has been 25 transmitted and received. When used without DNSSEC, ZONEMD functions 26 as a checksum, guarding only against unintentional changes. 28 ZONEMD does not replace DNSSEC. Whereas DNSSEC protects individual 29 RRSets (DNS data with fine granularity), ZONEMD protects a zone's 30 data as a whole, whether consumed by authoritative name servers, 31 recursive name servers, or any other applications. 33 As specified herein, ZONEMD is impractical for large, dynamic zones 34 due to the time and resources required for digest calculation. 35 However, The ZONEMD record is extensible so that new digest schemes 36 may be added in the future to support large, dynamic zones. 38 Status of This Memo 40 This Internet-Draft is submitted in full conformance with the 41 provisions of BCP 78 and BCP 79. 43 Internet-Drafts are working documents of the Internet Engineering 44 Task Force (IETF). Note that other groups may also distribute 45 working documents as Internet-Drafts. The list of current Internet- 46 Drafts is at https://datatracker.ietf.org/drafts/current/. 48 Internet-Drafts are draft documents valid for a maximum of six months 49 and may be updated, replaced, or obsoleted by other documents at any 50 time. It is inappropriate to use Internet-Drafts as reference 51 material or to cite them other than as "work in progress." 53 This Internet-Draft will expire on April 18, 2021. 55 Copyright Notice 57 Copyright (c) 2020 IETF Trust and the persons identified as the 58 document authors. All rights reserved. 60 This document is subject to BCP 78 and the IETF Trust's Legal 61 Provisions Relating to IETF Documents 62 (https://trustee.ietf.org/license-info) in effect on the date of 63 publication of this document. Please review these documents 64 carefully, as they describe your rights and restrictions with respect 65 to this document. Code Components extracted from this document must 66 include Simplified BSD License text as described in Section 4.e of 67 the Trust Legal Provisions and are provided without warranty as 68 described in the Simplified BSD License. 70 Table of Contents 72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 73 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4 74 1.2. Alternative Approaches . . . . . . . . . . . . . . . . . 4 75 1.3. Design Overview . . . . . . . . . . . . . . . . . . . . . 6 76 1.4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 6 77 1.4.1. Root Zone . . . . . . . . . . . . . . . . . . . . . . 6 78 1.4.2. Providers, Secondaries, and Anycast . . . . . . . . . 7 79 1.4.3. Response Policy Zones . . . . . . . . . . . . . . . . 7 80 1.4.4. Centralized Zone Data Service . . . . . . . . . . . . 7 81 1.4.5. General Purpose Comparison Check . . . . . . . . . . 7 82 1.5. Terminology . . . . . . . . . . . . . . . . . . . . . . . 8 83 2. The ZONEMD Resource Record . . . . . . . . . . . . . . . . . 8 84 2.1. Non-apex ZONEMD Records . . . . . . . . . . . . . . . . . 8 85 2.2. ZONEMD RDATA Wire Format . . . . . . . . . . . . . . . . 8 86 2.2.1. The Serial Field . . . . . . . . . . . . . . . . . . 9 87 2.2.2. The Scheme Field . . . . . . . . . . . . . . . . . . 9 88 2.2.3. The Hash Algorithm Field . . . . . . . . . . . . . . 9 89 2.2.4. The Digest Field . . . . . . . . . . . . . . . . . . 10 90 2.3. ZONEMD Presentation Format . . . . . . . . . . . . . . . 10 91 2.4. ZONEMD Example . . . . . . . . . . . . . . . . . . . . . 10 92 2.5. Including ZONEMD RRs in a Zone . . . . . . . . . . . . . 10 93 3. Calculating the Digest . . . . . . . . . . . . . . . . . . . 11 94 3.1. Add ZONEMD Placeholder . . . . . . . . . . . . . . . . . 11 95 3.2. Optionally Sign the Zone . . . . . . . . . . . . . . . . 12 96 3.3. Scheme-Specific Processing . . . . . . . . . . . . . . . 12 97 3.3.1. The SIMPLE Scheme . . . . . . . . . . . . . . . . . . 12 98 3.3.1.1. SIMPLE Scheme Inclusion/Exclusion Rules . . . . . 12 99 3.3.1.2. SIMPLE Scheme Digest Calculation . . . . . . . . 13 100 3.4. Update ZONEMD RR . . . . . . . . . . . . . . . . . . . . 13 101 4. Verifying Zone Digest . . . . . . . . . . . . . . . . . . . . 13 102 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 103 5.1. ZONEMD RRtype . . . . . . . . . . . . . . . . . . . . . . 15 104 5.2. ZONEMD Scheme . . . . . . . . . . . . . . . . . . . . . . 15 105 5.3. ZONEMD Hash Algorithm . . . . . . . . . . . . . . . . . . 16 106 6. Security Considerations . . . . . . . . . . . . . . . . . . . 16 107 6.1. Using Zone Digest Without DNSSEC . . . . . . . . . . . . 16 108 6.2. Attacks Against the Zone Digest . . . . . . . . . . . . . 16 109 6.3. Use of Multiple ZONEMD Hash Algorithms . . . . . . . . . 17 110 6.4. DNSSEC Timing Considerations . . . . . . . . . . . . . . 17 111 6.5. Attacks Utilizing ZONEMD Queries . . . . . . . . . . . . 17 112 6.6. Resilience and Fragility . . . . . . . . . . . . . . . . 18 113 7. Performance Considerations . . . . . . . . . . . . . . . . . 18 114 7.1. SIMPLE SHA384 . . . . . . . . . . . . . . . . . . . . . . 18 115 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 19 116 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 117 10. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 19 118 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 27 119 11.1. Normative References . . . . . . . . . . . . . . . . . . 27 120 11.2. Informative References . . . . . . . . . . . . . . . . . 27 121 Appendix A. Example Zones With Digests . . . . . . . . . . . . . 30 122 A.1. Simple EXAMPLE Zone . . . . . . . . . . . . . . . . . . . 30 123 A.2. Complex EXAMPLE Zone . . . . . . . . . . . . . . . . . . 30 124 A.3. EXAMPLE Zone with multiple digests . . . . . . . . . . . 31 125 A.4. The URI.ARPA Zone . . . . . . . . . . . . . . . . . . . . 32 126 A.5. The ROOT-SERVERS.NET Zone . . . . . . . . . . . . . . . . 35 127 Appendix B. Implementation Status . . . . . . . . . . . . . . . 37 128 B.1. Authors' Implementation . . . . . . . . . . . . . . . . . 37 129 B.2. Shane Kerr's Implementation . . . . . . . . . . . . . . . 37 130 B.3. NIC Chile Labs Implementation . . . . . . . . . . . . . . 38 131 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 133 1. Introduction 135 In the DNS, a zone is the collection of authoritative resource 136 records (RRs) sharing a common origin ([RFC8499]). Zones are often 137 stored as files in the so-called master file format [RFC1034]. Zones 138 are generally distributed among name servers using the AXFR (zone 139 transfer [RFC5936]), and IXFR (incremental zone transfer [RFC1995]) 140 protocols. They can also be distributed outside of the DNS, with any 141 file transfer protocol such as FTP, HTTP, and rsync, or even as email 142 attachments. Currently, there is no standard way to compute a hash 143 or message digest for a stand-alone zone. 145 This document specifies an RR type that provides a cryptographic 146 message digest of the data in a zone. It allows a receiver of the 147 zone to verify the zone's integrity and authenticity when used in 148 combination with DNSSEC. The digest RR is a part of the zone itself, 149 allowing verification of the zone, no matter how it is transmitted. 150 The digest uses the wire format of zone data in a canonical ordering. 151 Thus, it is independent of presentation format, such as whitespace, 152 capitalization, and comments. 154 This specification is OPTIONAL to implement by both publishers and 155 consumers of zone data. 157 1.1. Motivation 159 The primary motivation for this protocol enhancement is the desire to 160 verify the data integrity and origin authenticity of a stand-alone 161 zone, regardless of how it is transmitted. A consumer of zone data 162 should be able to verify that it is as-published by the zone 163 operator. 165 Note, however, that integrity and authenticity can only be assured 166 when the zone is signed. DNSSEC provides three strong security 167 guarantees relevant to this protocol: 169 1. whether or not to expect DNSSEC records in the zone, 171 2. whether or not to expect a ZONEMD record in a signed zone, and 173 3. whether or not the ZONEMD record has been altered since it was 174 signed. 176 A secondary motivation is to provide the equivalent of a checksum, 177 allowing a zone recipient to check for unintended changes and 178 operational errors, such as accidental truncation. 180 1.2. Alternative Approaches 182 One approach to preventing data tampering and corruption is to secure 183 the distribution channel. The DNS has a number of features that are 184 already used for channel security. Perhaps the most widely used is 185 DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared secret 186 keys and a message digest to protect individual query and response 187 messages. It is generally used to authenticate and validate UPDATE 188 [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages. 190 DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another 191 protocol extension that authenticates individual DNS transactions. 192 Whereas SIG records normally cover specific RR types, SIG(0) is used 193 to sign an entire DNS message. Unlike TSIG, SIG(0) uses public key 194 cryptography rather than shared secrets. 196 The Transport Layer Security protocol suite also provides channel 197 security. The DPRIVE working group is in the process of specifying 198 DNS Zone Transfer-over-TLS [I-D.ietf-dprive-xfr-over-tls]. One can 199 also easily imagine the distribution of zones over HTTPS-enabled web 200 servers, as well as DNS-over-HTTPS [RFC8484]. 202 Unfortunately, the protections provided by these channel security 203 techniques are (in practice) ephemeral and are not retained after the 204 data transfer is complete. They ensure that the client receives the 205 data from the expected server, and that the data sent by the server 206 is not modified during transmission. However, they do not guarantee 207 that the server transmits the data as originally published, and do 208 not provide any methods to verify data that is read after 209 transmission is complete. For example, a name server loading saved 210 zone data upon restart cannot guarantee that the on-disk data has not 211 been modified. Such modification could be the result of an 212 accidental corruption of the file, or perhaps an incompletely saved 213 file [disk-full-failure]. For these reasons, it is preferable to 214 protect the integrity of the data itself. 216 Why not simply rely on DNSSEC, which provides certain data security 217 guarantees? For zones that are signed, a recipient could validate 218 all of the signed RRSets. Additionally, denial-of-existence records 219 prove that RRSets have not been added or removed. However, 220 delegations (non-apex NS records) are not signed by DNSSEC, and 221 neither are any glue records. ZONEMD protects the integrity of 222 delegation, glue, and other records that are not otherwise covered by 223 DNSSEC. Furthermore, zones that employ NSEC3 with opt-out [RFC5155] 224 are susceptible to the removal or addition of names between the 225 signed nodes. Whereas DNSSEC primarily protects consumers of DNS 226 response messages, this protocol protects consumers of zones. 228 There are existing tools and protocols that provide data security, 229 such as OpenPGP [RFC4880] and S/MIME [RFC5751]. In fact, the 230 internic.net site publishes PGP signatures alongside the root zone 231 and other files available there. However, this is a detached 232 signature with no strong association to the corresponding zone file 233 other than its timestamp. Non-detached signatures are, of course, 234 possible, but these necessarily change the format of the file being 235 distributed; a zone signed with OpenPGP or S/MIME no longer looks 236 like a DNS zone and could not directly be loaded into a name server. 237 Once loaded the signature data is lost, so it cannot be further 238 propagated. 240 It seems the desire for data security in DNS zones was envisioned as 241 far back as 1997. [RFC2065] is an obsoleted specification of the 242 first generation DNSSEC Security Extensions. It describes a zone 243 transfer signature, identified as the AXFR SIG, which is similar to 244 the technique proposed by this document. That is, it proposes 245 ordering all (signed) RRSets in a zone, hashing their contents, and 246 then signing the zone hash. The AXFR SIG is described only for use 247 during zone transfers. It did not postulate the need to validate 248 zone data distributed outside of the DNS. Furthermore, its 249 successor, [RFC2535], omits the AXFR SIG, while at the same time 250 introducing an IXFR SIG. 252 1.3. Design Overview 254 This document specifies a new Resource Record type to convey a 255 message digest of the content of a zone. The digest is calculated at 256 the time of zone publication. If the zone is signed with DNSSEC, any 257 modifications of the digest can be detected. The procedures for 258 digest calculation and DNSSEC signing are similar. Both require data 259 to be processed in a well-defined order and format. It may be 260 possible to perform DNSSEC signing and digest calculation in 261 parallel. 263 The zone digest is designed to be used on zones that have infrequent 264 updates. As specified herein, the digest is re-calculated over the 265 entire zone content each time the zone is updated. This 266 specification does not provide an efficient mechanism for updating 267 the digest on incremental updates of zone data. It is, however, 268 extensible so that future schemes may be defined to support efficient 269 incremental digest updates. 271 It is expected that verification of a zone digest will be implemented 272 in name server software. That is, a name server can verify the zone 273 data it was given and refuse to serve a zone which fails 274 verification. For signed zones, the name server needs a trust anchor 275 to perform DNSSEC validation. For signed non-root zones, the name 276 server may need to send queries to validate a chain of trust. Digest 277 verification could also be performed externally. 279 1.4. Use Cases 281 1.4.1. Root Zone 283 The root zone [InterNIC] is one of the most widely distributed DNS 284 zone on the Internet, served by more than 1000 separate instances 285 [RootServers] at the time of this writing. Additionally, many 286 organizations configure their own name servers to serve the root zone 287 locally. Reasons for doing so include privacy and reduced access 288 time. [RFC8806] describes one way to do this. As the root zone 289 spreads beyond its traditional deployment boundaries, the 290 verification of the completeness of the zone contents becomes more 291 important. 293 1.4.2. Providers, Secondaries, and Anycast 295 Since its very early days, the developers of the DNS recognized the 296 importance of secondary name servers and service diversity. However, 297 modern DNS service has complex provisioning which includes multiple 298 third-party providers ([RFC8901]) and hundreds of anycast instances 299 ([RFC3258]). Instead of a simple primary-to-secondary zone 300 distribution system, today it is possible to have multiple levels, 301 multiple parties, and multiple protocols involved in the distribution 302 of zone data. This complexity introduces new places for problems to 303 arise. The zone digest protects the integrity of data that flows 304 through such systems. 306 1.4.3. Response Policy Zones 308 A Response Policy Zone (RPZ) is "a mechanism to introduce a 309 customized policy in Domain Name System servers, so that recursive 310 resolvers return possibly modified results" [RPZ]. The policy 311 information is carried inside specially constructed DNS zones. A 312 number of companies provide RPZ feeds, which are consumed by name 313 server and firewall products. While RPZ zones can be signed with 314 DNSSEC, the data is not queried directly, and would not be subject to 315 DNSSEC validation. 317 1.4.4. Centralized Zone Data Service 319 ICANN operates the Centralized Zone Data Service [CZDS], which is a 320 repository of top-level domain zone files. Users that have been 321 granted access are then able to download zone data. Adding a zone 322 digest to these would provide CZDS users with assurances that the 323 data has not been modified between origination and retrieval. Note 324 that ZONEMD could be added to zone data supplied to CZDS without 325 requiring it to be present in the zone data served by production name 326 servers, since the digest is inherently attached to the specific copy 327 of the zone. 329 1.4.5. General Purpose Comparison Check 331 Since the zone digest calculation does not depend on presentation 332 format, it could be used to compare multiple copies of a zone 333 received from different sources, or copies generated by different 334 processes. In this case, it serves as a checksum and can be useful 335 even for unsigned zones. 337 1.5. Terminology 339 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 340 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 341 "OPTIONAL" in this document are to be interpreted as described in BCP 342 14 [RFC2119] [RFC8174] when, and only when, they appear in all 343 capitals, as shown here. 345 The terms Private Use, Reserved, Unassigned, and Specification 346 Required are to be interpreted as defined in [RFC8126]. 348 2. The ZONEMD Resource Record 350 This section describes the ZONEMD Resource Record, including its 351 fields, wire format, and presentation format. The Type value for the 352 ZONEMD RR is 63. The ZONEMD RR is class independent. The RDATA of 353 the resource record consists of four fields: Serial, Scheme, Hash 354 Algorithm, and Digest. 356 2.1. Non-apex ZONEMD Records 358 This document specifies ZONEMD RRs located at the zone apex. Non- 359 apex ZONEMD RRs are not forbidden, but have no meaning in this 360 specification. Non-apex ZONEMD RRs MUST NOT be used for 361 verification. 363 During digest calculation, non-apex ZONEMD RRs are treated as 364 ordinary RRs. They are digested as-is and the RR is not replaced by 365 a placeholder RR. 367 Unless explicitly stated otherwise, "ZONEMD" always refers to apex 368 records throughout this document. 370 2.2. ZONEMD RDATA Wire Format 372 The ZONEMD RDATA wire format is encoded as follows: 374 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 375 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 1 376 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 377 | Serial | 378 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 379 | Scheme |Hash Algorithm | | 380 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 381 | Digest | 382 / / 383 / / 384 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 386 2.2.1. The Serial Field 388 The Serial field is a 32-bit unsigned integer in network byte order. 389 It is the serial number from the zone's SOA record ([RFC1035] section 390 3.3.13) for which the zone digest was generated. 392 It is included here to clearly bind the ZONEMD RR to a particular 393 version of the zone's content. Without the serial number, a stand- 394 alone ZONEMD digest has no obvious association to any particular 395 instance of a zone. 397 2.2.2. The Scheme Field 399 The Scheme field is an 8-bit unsigned integer that identifies the 400 methods by which data is collated and presented as input to the 401 hashing function. 403 Herein, SIMPLE, with Scheme value 1, is the only standardized Scheme 404 defined for ZONEMD records and it MUST be supported by 405 implementations. The Scheme registry is further described in 406 Section 5. 408 Scheme values 240-254 are allocated for Private Use. 410 2.2.3. The Hash Algorithm Field 412 The Hash Algorithm field is an 8-bit unsigned integer that identifies 413 the cryptographic hash algorithm used to construct the digest. 415 Herein, SHA384 [RFC6234], with Hash Algorithm value 1, is the only 416 standardized Hash Algorithm defined for ZONEMD records that MUST be 417 supported by implementations. When SHA384 is used, the size of the 418 Digest field is 48 octets. The result of the SHA384 digest algorithm 419 MUST NOT be truncated, and the entire 48 octet digest is published in 420 the ZONEMD record. 422 SHA512 [RFC6234], with Hash Algorithm value 2, is also defined for 423 ZONEMD records, and SHOULD be supported by implementations. When 424 SHA512 is used, the size of the Digest field is 64 octets. The 425 result of the SHA512 digest algorithm MUST NOT be truncated, and the 426 entire 64 octet digest is published in the ZONEMD record. 428 Hash Algorithm values 240-254 are allocated for Private Use. 430 The Hash Algorithm registry is further described in Section 5. 432 2.2.4. The Digest Field 434 The Digest field is a variable-length sequence of octets containing 435 the output of the hash algorithm. The length of the Digest field is 436 determined by deducting the fixed size of the Serial, Scheme, and 437 Hash Algorithm fields from the RDATA size in the ZONEMD RR header. 439 The Digest field MUST NOT be shorter than 12 octets. Digests for the 440 SHA384 and SHA512 hash algorithms specified herein are never 441 truncated. Digests for future hash algorithms MAY be truncated, but 442 MUST NOT be truncated to a length that results in less than 96-bits 443 (12 octets) of equivalent strength. 445 Section 3 describes how to calculate the digest for a zone. 446 Section 4 describes how to use the digest to verify the contents of a 447 zone. 449 2.3. ZONEMD Presentation Format 451 The presentation format of the RDATA portion is as follows: 453 The Serial field is represented as an unsigned decimal integer. 455 The Scheme field is represented as an unsigned decimal integer. 457 The Hash Algorithm field is represented as an unsigned decimal 458 integer. 460 The Digest is represented as a sequence of case-insensitive 461 hexadecimal digits. Whitespace is allowed within the hexadecimal 462 text. 464 2.4. ZONEMD Example 466 The following example shows a ZONEMD RR in presentation format: 468 example.com. 86400 IN ZONEMD 2018031500 1 1 ( 469 FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE 470 7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE ) 472 2.5. Including ZONEMD RRs in a Zone 474 The zone operator chooses an appropriate hash algorithm and scheme, 475 and includes the calculated zone digest in the apex ZONEMD RRset. 476 The zone operator MAY choose any of the defined hash algorithms and 477 schemes, including the private use code points. 479 The ZONEMD RRSet MAY contain multiple records to support algorithm 480 agility [RFC7696]. [RFC Editor: change that to BCP 201] When 481 multiple ZONEMD RRs are present, each MUST specify a unique Scheme 482 and Hash Algorithm tuple. It is RECOMMENDED that a zone include only 483 one ZONEMD RR, unless the zone operator is in the process of 484 transitioning to a new scheme or hash algorithm. 486 3. Calculating the Digest 488 The algorithm described in this section is designed for the common 489 case of offline DNSSEC signing. Slight deviations may be permitted 490 or necessary in other situations, such as with unsigned zones or 491 online DNSSEC signing. Implementations that deviate from the 492 described algorithm are advised to ensure that it produces ZONEMD 493 RRs, signatures, and dential-of-existence records that are identical 494 to the ones generated by this procedure. 496 3.1. Add ZONEMD Placeholder 498 In preparation for calculating the zone digest(s), any existing 499 ZONEMD records (and covering RRSIGs) at the zone apex are first 500 deleted. 502 Prior to calculation of the digest, and prior to signing with DNSSEC, 503 one or more placeholder ZONEMD records are added to the zone apex. 504 This ensures that denial-of-existence (NSEC, NSEC3) records are 505 created correctly if the zone is signed with DNSSEC. If placeholders 506 were not added prior to signing, the later addition of ZONEMD records 507 would also require updating the Type Bit Maps field of any apex NSEC/ 508 NSEC3 RRs, which then invalidates the calculated digest value. 510 When multiple ZONEMD RRs are published in the zone, e.g., during an 511 algorithm rollover, each MUST specify a unique Scheme and Hash 512 Algorithm tuple. 514 It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of 515 the SOA. However, the TTL of the ZONEMD record may be safely ignored 516 during verification in all cases. 518 In the placeholder record, the Serial field is set to the current SOA 519 Serial. The Scheme field is set to the value for the chosen 520 collation scheme. The Hash Algorithm field is set to the value for 521 the chosen hash algorithm. Since apex ZONEMD records are excluded 522 from digest calculation, the value of the Digest field does not 523 matter at this point in the process. 525 3.2. Optionally Sign the Zone 527 Following addition of placeholder records, the zone may be signed 528 with DNSSEC. When the digest calculation is complete, and the ZONEMD 529 record is updated, the signature(s) for the ZONEMD RRSet MUST be 530 recalculated and updated as well. Therefore, the signer is not 531 required to calculate a signature over the placeholder record at this 532 step in the process, but it is harmless to do so. 534 3.3. Scheme-Specific Processing 536 Herein, only the SIMPLE collation scheme is defined. Additional 537 schemes may be defined in future updates to this document. 539 3.3.1. The SIMPLE Scheme 541 For the SIMPLE scheme, the digest is calculated over the zone as a 542 whole. This means that a change to a single RR in the zone requires 543 iterating over all RRs in the zone to recalculate the digest. SIMPLE 544 is a good choice for zones that are small and/or stable, but probably 545 not good for zones that are large and/or dynamic. 547 Calculation of a zone digest requires RRs to be processed in a 548 consistent format and ordering. This specification uses DNSSEC's 549 canonical on-the-wire RR format (without name compression) and 550 ordering as specified in Sections 6.1, 6.2, and 6.3 of [RFC4034] with 551 the additional provision that RRSets having the same owner name MUST 552 be numerically ordered, in ascending order, by their numeric RR TYPE. 554 3.3.1.1. SIMPLE Scheme Inclusion/Exclusion Rules 556 When iterating over records in the zone, the following inclusion/ 557 exclusion rules apply: 559 o All records in the zone, including glue records, MUST be included, 560 unless excluded by a subsequent rule. 562 o Occluded data ([RFC5936] Section 3.5) MUST be included. 564 o If there are duplicate RRs with equal owner, class, type, and 565 RDATA, only one instance is included ([RFC4034] Section 6.3), and 566 the duplicates MUST be omitted. 568 o The placeholder apex ZONEMD RR(s) MUST NOT be included. 570 o If the zone is signed, DNSSEC RRs MUST be included, except: 572 o The RRSIG covering the apex ZONEMD RRSet MUST NOT be included 573 because the RRSIG will be updated after all digests have been 574 calculated. 576 3.3.1.2. SIMPLE Scheme Digest Calculation 578 A zone digest using the SIMPLE scheme is calculated by concatenating 579 all RRs in the zone, in the format and order described in 580 Section 3.3.1 subject to the inclusion/exclusion rules described in 581 Section 3.3.1.1, and then applying the chosen hash algorithm: 583 digest = hash( RR(1) | RR(2) | RR(3) | ... ) 585 where "|" denotes concatenation. 587 3.4. Update ZONEMD RR 589 The calculated zone digest is inserted into the placeholder ZONEMD 590 RR. Repeat for each digest if multiple digests are to be published. 592 If the zone is signed with DNSSEC, the RRSIG record(s) covering the 593 ZONEMD RRSet MUST then be added or updated. Because the ZONEMD 594 placeholder was added prior to signing, the zone will already have 595 the appropriate denial-of-existence (NSEC, NSEC3) records. 597 Some DNSSEC implementations (especially "online signing") might 598 update the SOA serial number whenever a new signature is made. To 599 preserve the calculated digest, generation of a ZONEMD signature MUST 600 NOT also result in a change to the SOA serial number. The ZONEMD RR 601 and the matching SOA MUST be published at the same time. 603 4. Verifying Zone Digest 605 The recipient of a zone that has a ZONEMD RR verifies the zone by 606 calculating the digest as follows. If multiple ZONEMD RRs are 607 present in the zone, e.g., during an algorithm rollover, a match 608 using any one of the recipient's supported Schemes and Hash 609 Algorithms is sufficient to verify the zone. The verifier MAY ignore 610 a ZONEMD RR if its Scheme and Hash Algorithm violates local policy. 612 1. The verifier MUST first determine whether or not to expect DNSSEC 613 records in the zone. By examining locally configured trust 614 anchors, and, if necessary, querying for and validating DS RRs in 615 the parent zone, the verifier knows whether or not the zone to be 616 verified should include DNSSEC keys and signatures. For zones 617 where signatures are not expected, or if DNSSEC validation is not 618 performed, digest verification continues at step 4 below. 620 2. For zones where signatures are expected, the existence of the 621 apex ZONEMD record MUST be validated. If the DNSSEC data proves 622 the ZONEMD RRSet does not exist, digest verification cannot 623 occur. If the DNSSEC data proves the ZONEMD does exist, but is 624 not found in the zone, digest verification MUST NOT be considered 625 successful. 627 3. For zones where signatures are expected, the SOA and ZONEMD 628 RRSets MUST have valid signatures, chaining up to a trust anchor. 629 If DNSSEC validation of the SOA or ZONEMD RRSets fails, digest 630 verification MUST NOT be considered successful. 632 4. When multiple ZONEMD RRs are present, each MUST specify a unique 633 Scheme and Hash Algorithm tuple. If the ZONEMD RRSet contains 634 more than one RR with the same Scheme and Hash Algorithm, digest 635 verification for those ZONEMD RRs MUST NOT be considered 636 successful. 638 5. Loop over all apex ZONEMD RRs and perform the following steps: 640 A. The SOA Serial field MUST exactly match the ZONEMD Serial 641 field. If the fields do not match, digest verification MUST 642 NOT be considered successful with this ZONEMD RR. 644 B. The Scheme field MUST be checked. If the verifier does not 645 support the given scheme, verification MUST NOT be considered 646 successful with this ZONEMD RR. 648 C. The Hash Algorithm field MUST be checked. If the verifier 649 does not support the given hash algorithm, verification MUST 650 NOT be considered successful with this ZONEMD RR. 652 D. The Digest field size MUST be checked. If the size of the 653 given Digest field is smaller than 12 octets, or if the size 654 is not equal to the size expected for the corresponding Hash 655 Algorithm, verification MUST NOT be considered successful 656 with this ZONEMD RR. 658 E. The zone digest is computed over the zone data as described 659 in Section 3.3, using the Scheme and Hash Algorithm for the 660 current ZONEMD RR. 662 F. The computed digest is compared to the received digest. If 663 the two digest values match, verification is considered 664 successful. Otherwise, verification MUST NOT be considered 665 successful for this ZONEMD RR. 667 Each time zone verification is performed, the verifier SHOULD report 668 the status as either successful or unsuccessful. When unsuccessful, 669 the verifier SHOULD report the reason(s) that verification did not 670 succeed. 672 5. IANA Considerations 674 5.1. ZONEMD RRtype 676 This document defines a new DNS RR type, ZONEMD, whose value 63 has 677 been allocated by IANA from the "Resource Record (RR) TYPEs" 678 subregistry of the "Domain Name System (DNS) Parameters" registry: 680 Type: ZONEMD 682 Value: 63 684 Meaning: Message Digest Over Zone Data 686 Reference: [this document] 688 5.2. ZONEMD Scheme 690 IANA is requested to create a new registry on the "Domain Name System 691 (DNS) Parameters" web page as follows: 693 Registry Name: ZONEMD Schemes 695 Registration Procedure: Specification Required 697 Reference: [this document] 699 +---------+-------------------------+----------+-----------------+ 700 | Value | Description | Mnemonic | Reference | 701 +---------+-------------------------+----------+-----------------+ 702 | 0 | Reserved | | | 703 | 1 | Simple ZONEMD collation | SIMPLE | [this document] | 704 | 2-239 | Unassigned | | | 705 | 240-254 | Private Use | N/A | [this document] | 706 | 255 | Reserved | | | 707 +---------+-------------------------+----------+-----------------+ 709 Table 1: ZONEMD Scheme Registry 711 5.3. ZONEMD Hash Algorithm 713 IANA is requested to create a new registry on the "Domain Name System 714 (DNS) Parameters" web page as follows: 716 Registry Name: ZONEMD Hash Algorithms 718 Registration Procedure: Specification Required 720 Reference: [this document] 722 +---------+-------------+----------+-----------------+ 723 | Value | Description | Mnemonic | Reference | 724 +---------+-------------+----------+-----------------+ 725 | 0 | Reserved | | | 726 | 1 | SHA-384 | SHA384 | [this document] | 727 | 2 | SHA-512 | SHA512 | [this document] | 728 | 3-239 | Unassigned | | | 729 | 240-254 | Private Use | N/A | [his document] | 730 | 255 | Reserved | | | 731 +---------+-------------+----------+-----------------+ 733 Table 2: ZONEMD Hash Algorithm Registry 735 6. Security Considerations 737 6.1. Using Zone Digest Without DNSSEC 739 Users of ZONEMD with unsigned zones are advised that it provides no 740 real protection against attacks. While zone digests can be used in 741 the absence of DNSSEC, this only provides protection against 742 accidental zone corruption, such as transmission errors and 743 truncation. When used in this manner, it effectively serves only as 744 a checksum. For zones not signed with DNSSEC, an attacker can make 745 any zone modifications appear to be valid by recomputing Digest field 746 of a ZONEMD RR. 748 6.2. Attacks Against the Zone Digest 750 An attacker, whose goal is to modify zone content before it is used 751 by the victim, may consider a number of different approaches. 753 The attacker might perform a downgrade attack to an unsigned zone. 754 This is why Section 4 talks about determining whether or not to 755 expect DNSSEC signatures for the zone in step 1. 757 The attacker might perform a downgrade attack by removing one or more 758 ZONEMD records. Such a removal is detectable only with DNSSEC 759 validation and is why Section 4 talks about checking denial-of- 760 existence proofs in step 2 and signature validation in step 3. 762 The attacker might alter the Scheme, Hash Algorithm, or Digest fields 763 of the ZONEMD record. Such modifications are detectable only with 764 DNSSEC validation. 766 As stated in [RFC7696], cryptographic algorithms age and become 767 weaker as cryptanalysis techniques and computing resources improve 768 with time. Implementors and publishers of zone digests should 769 anticipate the need for algorithm agility on long timescales. 771 6.3. Use of Multiple ZONEMD Hash Algorithms 773 When a zone publishes multiple ZONEMD RRs, the overall security is 774 only as good as the weakest hash algorithm in use. For this reason, 775 Section 2 recommends only publishing multiple ZONEMD RRs when 776 transitioning to a new scheme or hash algorithm. Once the transition 777 is complete, the old scheme or hash algorithm should be removed from 778 the ZONEMD RRSet. 780 6.4. DNSSEC Timing Considerations 782 As with all DNSSEC signatures, the ability to perform signature 783 validation of a ZONEMD record is limited in time. If the DS 784 record(s) or trust anchors for the zone to be verified are no longer 785 available, the recipient cannot validate the ZONEMD RRSet. This 786 could happen even if the ZONEMD signature is still current (not 787 expired), since the zone's DS record(s) may have been withdrawn 788 following a Key Signing Key (KSK) rollover. 790 For zones where it may be important to validate a ZONEMD RRSet 791 through its entire signature validity period, the zone operator 792 should ensure that KSK rollover timing takes this into consideration. 794 6.5. Attacks Utilizing ZONEMD Queries 796 Nothing in this specification prevents clients from making, and 797 servers from responding to, ZONEMD queries. Servers SHOULD NOT 798 calculate zone digests dynamically (for each query) as this can be 799 used as a CPU resource exhaustion attack. 801 ZONEMD responses could be used in a distributed denial-of-service 802 amplification attack. The ZONEMD RR is moderately sized, much like 803 the DS RR. A single ZONEMD RR contributes approximately 65 to 95 804 octets to a DNS response, for digest types defined herein. Other RR 805 types, such as DNSKEY, can result in larger amplification effects. 807 6.6. Resilience and Fragility 809 ZONEMD is used to detect incomplete or corrupted zone data prior to 810 its use, thereby increasing resilience by not using corrupt data, but 811 also introduces some denial-of-service fragility by making good data 812 in a zone unavailable if some other data is missing or corrupt. 813 Publishers and consumers of zones containing ZONEMD records should be 814 aware of these tradeoffs. While the intention is to secure the zone 815 data, misconfigurations or implementation bugs are generally 816 indistinguishable from intentional tampering, and could lead to 817 service failures when verification is performed automatically. 819 Zone publishers may want to deploy ZONEMD gradually, perhaps by 820 utilizing one of the private use hash algorithm code points listed in 821 Section 5.3. Similarly, recipients may want to initially configure 822 verification failures only as a warning, and later as an error after 823 gaining experience and confidence with the feature. 825 7. Performance Considerations 827 This section is provided to make zone publishers aware of the 828 performance requirements and implications of including ZONEMD RRs in 829 a zone. 831 7.1. SIMPLE SHA384 833 As mentioned previously, the SIMPLE scheme may be impractical for use 834 in zones that are either large or highly dynamic. Zone publishers 835 should carefully consider the use of ZONEMD in such zones, since it 836 might cause consumers of zone data (e.g., secondary name servers) to 837 expend resources on digest calculation. For such use cases, it is 838 recommended that ZONEMD only be used when digest calculation time is 839 significantly less than propagation times and update intervals. 841 The authors' implementation (Appendix B.1) includes an option to 842 record and report CPU usage of its operation. The software was used 843 to generate digests for more than 800 TLD zones available from 844 [CZDS]. The table below summarizes the results for the SIMPLE scheme 845 and SHA384 hash algorithm grouped by zone size. The Rate column is 846 the mean amount of time per RR to calculate the digest, running on 847 commodity hardware in early 2020. 849 +---------------------+----------------+ 850 | Zone Size (RRs) | Rate (msec/RR) | 851 +---------------------+----------------+ 852 | 10 - 99 | 0.00683 | 853 | 100 - 999 | 0.00551 | 854 | 1000 - 9999 | 0.00505 | 855 | 10000 - 99999 | 0.00602 | 856 | 100000 - 999999 | 0.00845 | 857 | 1000000 - 9999999 | 0.0108 | 858 | 10000000 - 99999999 | 0.0148 | 859 +---------------------+----------------+ 861 For example, based on the above table, it takes approximately 0.13 862 seconds to calculate a SIMPLE SHA384 digest for a zone with 22,000 863 RRs, and about 2.5 seconds for a zone with 300,000 RRs. 865 These benchmarks attempt to emulate a worst-case scenario and take 866 into account the time required to canonicalize the zone for 867 processing. Each of the 800+ zones were measured three times, and 868 then averaged, with a different random sorting of the input data 869 prior to each measurement. 871 8. Privacy Considerations 873 This specification has no impact on user privacy. 875 9. Acknowledgments 877 The authors wish to thank David Blacka, Scott Hollenbeck, and Rick 878 Wilhelm for providing feedback on early drafts of this document. 879 Additionally, they thank Joe Abley, Mark Andrews, Ralph Dolmans, 880 Donald Eastlake, Richard Gibson, Olafur Gudmundsson, Bob Harold, Paul 881 Hoffman, Evan Hunt, Shumon Huque, Tatuya Jinmei, Mike St. Johns, Burt 882 Kaliski, Shane Kerr, Matt Larson, Barry Leiba, John Levine, Ed Lewis, 883 Matt Pounsett, Mukund Sivaraman, Petr Spacek, Ondrej Sury, Willem 884 Toorop, Florian Weimer, Tim Wicinski, Wouter Wijngaards, Paul 885 Wouters, and other members of the DNSOP working group for their 886 input. 888 10. Change Log 890 RFC Editor: Please remove this section before publication. 892 This section lists substantial changes to the document as it is being 893 worked on. 895 From -00 to -01: 897 o Removed requirement to sort by RR CLASS. 899 o Added Kumari and Hardaker as coauthors. 901 o Added Change Log section. 903 o Minor clarifications and grammatical edits. 905 From -01 to -02: 907 o Emphasize desire for data security over channel security. 909 o Expanded motivation into its own subsection. 911 o Removed discussion topic whether or not to include serial in 912 ZONEMD. 914 o Clarified that a zone's NS records always sort before the SOA 915 record. 917 o Clarified that all records in the zone must are digested, except 918 as specified in the exclusion rules. 920 o Added for discussion out-of-zone and occluded records. 922 o Clarified that update of ZONEMD signature must not cause a serial 923 number change. 925 o Added persons to acknowledgments. 927 From -02 to -03: 929 o Added recommendation to set ZONEMD TTL to SOA TTL. 931 o Clarified that digest input uses uncompressed names. 933 o Updated Implementations section. 935 o Changed intended status from Standards Track to Experimental and 936 added Scope of Experiment section. 938 o Updated Motivation, Introduction, and Design Overview sections in 939 response to working group discussion. 941 o Gave ZONEMD digest types their own status, separate from DS digest 942 types. Request IANA to create a registry. 944 o Added Reserved field for future work supporting dynamic updates. 946 o Be more rigorous about having just ONE ZONEMD record in the zone. 948 o Expanded use cases. 950 From -03 to -04: 952 o Added an appendix with example zones and digests. 954 o Clarified that only apex ZONEMD RRs shall be processed. 956 From -04 to -05: 958 o Made SHA384 the only supported ZONEMD digest type. 960 o Disassociated ZONEMD digest types from DS digest types. 962 o Updates to Introduction based on list feedback. 964 o Changed "zone file" to "zone" everywhere. 966 o Restored text about why ZONEMD has a Serial field. 968 o Clarified ordering of RRSets having same owner to be numerically 969 ascending. 971 o Clarified that all duplicate RRs (not just SOA) must be suppressed 972 in digest calculation. 974 o Clarified that the Reserved field must be set to zero and checked 975 for zero in verification. 977 o Clarified that occluded data must be included. 979 o Clarified procedure for verification, using temporary location for 980 received digest. 982 o Explained why Reserved field is 8-bits. 984 o IANA Considerations section now more specific. 986 o Added complex zone to examples. 988 o 990 From -05 to -06: 992 o RR type code 63 was assigned to ZONEMD by IANA. 994 From -06 to -07: 996 o Fixed mistakes in ZONEMD examples. 998 o Added private use Digest Type values 240-254. 1000 o Clarified that Digest field must not be empty. 1002 From -07 to draft-ietf-dnsop-dns-zone-digest-00: 1004 o Adopted by dnsop. 1006 o Clarified further that non-apex ZONEMD RRs have no meaning. 1008 o Changed "provably [un]signed" to "provably [in]secure". 1010 o Allow multiple ZONEMD RRs to support algorithm agility/rollovers. 1012 o Describe verification when there are multiple ZONEMD RRs. 1014 From -00 to -01: 1016 o Simplified requirements around verifying multiple digests. Any 1017 one match is sufficient. 1019 o Updated implementation notes. 1021 o Both implementations produce expected results on examples given in 1022 this document. 1024 From -01 to -02: 1026 o Changed the name of the Reserved field to Parameter. 1028 o Changed the name of Digest Type 1 from SHA384 to SHA384-STABLE. 1030 o The meaning of the Parameter field now depends on Digest Type. 1032 o No longer require Parameter field to be zero in verification. 1034 o Updated a rule from earlier versions that said multiple ZONEMD RRs 1035 were not allowed. 1037 From -02 to -03: 1039 o Changed the name of Digest Type 1 from SHA384-STABLE to 1040 SHA384-SIMPLE. 1042 o Changed document status from Experimental to Standards Track. 1044 o Removed Scope of Experimentation section. 1046 From -03 to -04: 1048 o Addressing WGLC feedback. 1050 o Changed from "Digest Type + Paramter" to "Scheme + Hash 1051 Algorithm". This should make it more obvious how ZONEMD can be 1052 expanded in the future with new schemes and hash algorithms, while 1053 sacrificing some of the flexibility that the Parameter was 1054 intended to provide. 1056 o Note: old RDATA fields: Serial, Digest Type, Parameter, Digest. 1058 o Note: new RDATA fields: Serial, Scheme, Hash Algorithm, Digest. 1060 o Add new IANA requirement for a Scheme registry. 1062 o Rearranged some sections and separated scheme-specific aspects 1063 from general aspects of digest calculation. 1065 o When discussing multiple ZONEMD RRs, allow for Scheme, as well as 1066 Hash Algorithm, transition. 1068 o Added Performance Considerations section with some benchmarks. 1070 o Further clarifications about non-apex ZONEMD RRs. 1072 o Clarified inclusion rule for duplicate RRs. 1074 o Removed or lowercased some inappropriately used RFC 2119 key 1075 words. 1077 o Clarified that all ZONEMD RRs, even for unsupported hash 1078 algorithms, must be zeroized during digest calculation. 1080 o Added Resilience and Fragility to security considerations. 1082 o Updated examples since changes in this version result in different 1083 hash values. 1085 From -04 to -05: 1087 o Clarifications about non-apex and multiple ZONEMD RRs. 1089 o Clarifications about benchmark results. 1091 o Don't compute ZONEMD on-the-fly. 1093 o Specification Required for updates to ZONEMD protocol registries. 1095 o Other rewording based on WGLC feedback. 1097 o Updated RFC numbers for some references. 1099 o Use documentation IP addresses instead of loopback. 1101 o Updated examples in the appendix. 1103 From -05 to -06: 1105 o Per WG suggestion, no longer include any apex ZONEMD record in 1106 digest calculation. 1108 o Updated examples in the appendix. 1110 o Clarified verification procedure by describing a loop over all 1111 ZONEMD RRs. 1113 From -06 to -07: 1115 o Added NIC Chile Labs implementation. 1117 From -07 to -08: 1119 o Update an author's affiliation. 1121 o Clarified why placeholder RRs are still important (for NSEC/ 1122 NSEC3). 1124 o Moved subsection ("Order of RRSets Having the Same Owner Name") 1125 with single sentence paragraph up into parent section. 1127 From -08 to -09: 1129 o Moved format, ordering, inclusion/exclusion into a sub section 1130 specific to the SIMPLE scheme. 1132 o Further clarified rules about multiple ZONEMD RRs (AD comments). 1134 o Reworded rules about processing of duplicate zone RRs (AD 1135 comments). 1137 o Removed sentence about optional zeroing of digest prior to 1138 calculation (AD comments). 1140 o Other minor changes (AD comments). 1142 From -09 to -10: 1144 o Add clarification and reference to on-disk modification / 1145 corruption of zone files. 1147 o Added concerns that timing of KSK rollovers could affect 1148 validation of ZONEMD record. 1150 o Addressed SECDIR review and accepted most proposed edits. 1152 o From SECDIR review, require minimum digest length of 12 octets. 1154 o From SECDIR review, add SHA512 has hash algorithm 2. 1156 o From SECDIR review, say that ZONEMD RRs MAY be ignored by local 1157 policy. 1159 o Moved Implementation Status to an appendix with the intention to 1160 retain it in RFC. 1162 o In registry tables, changed Status column to Implementation 1163 Requirement. 1165 From -10 to -11: 1167 o Fixed people's names in the acknowledgments section (blush) 1169 o Say "has not been modified between origination and retrieval." 1171 o Say that ZONEMD TTL doesn't matter during verification. 1173 o Further clarification that the SHA-384 and SHA-512 hashes are not 1174 truncated. Future algs might be truncated, but never below 96 1175 bits. 1177 From -11 to -12: 1179 o SECDIR review: make "recommended" all caps. 1181 o SECDIR review: tweak explanation of why ZONEMD RR has copy of SOA 1182 serial. 1184 o SECDIR review: be even more clear about apex ZONEMD RRs vs non- 1185 apex. 1187 o SECDIR review: Forgot to delete sentence about IANA policy for 1188 adding new hash algorithms. 1190 o SECDIR review: Spell out Key Signing Key first time. 1192 o SECDIR review: say "private use hash algorithm code points." 1194 o SECDIR review: Update estimates of ZONEMD RR size. 1196 From -12 to -13: 1198 o Added reference to draft-ietf-dprive-xfr-over-tls. 1200 o Dropped Implementation Requirement from registry tables. 1202 o Added Use of Multiple ZONEMD Hash Algorithms to Security 1203 Considerations. 1205 o Added Using Zone Digest Without DNSSEC to Security Considerations. 1207 o Added notes about the need for algorithm agility due to crypto 1208 algorithm aging. 1210 o Further clarified that only with DNSSEC can ZONEMD guarantee 1211 integrity and authenticity. 1213 o For unsigned zones, ZONEMD serves only as a checksum. 1215 o Calculation algorithm is designed for common case of offline 1216 signing. Deviations may be allowed as long as the end result is 1217 the same. 1219 o Numerous small edits and clarifications from IESG reviewer 1220 comments. 1222 From -13 to -14: 1224 o A few more edits and clarifications from IESG reviewer comments. 1226 o Moved paragraph about multiple digests to new section titled 1227 Including ZONEMD RRs in a Zone. 1229 o MUST be implemented -> MUST be supported by implementations. 1231 o Consolidated SHOULD requirements about error reporting to single 1232 place at the conclusion of verification. 1234 o Rephrased "provably insecure" etc as using DNSSEC validation to 1235 know whether or not the zone is expected to have keys and 1236 signatures. 1238 11. References 1240 11.1. Normative References 1242 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1243 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1244 . 1246 [RFC1035] Mockapetris, P., "Domain names - implementation and 1247 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1248 November 1987, . 1250 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1251 Requirement Levels", BCP 14, RFC 2119, 1252 DOI 10.17487/RFC2119, March 1997, 1253 . 1255 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1256 Rose, "Resource Records for the DNS Security Extensions", 1257 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1258 . 1260 [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms 1261 (SHA and SHA-based HMAC and HKDF)", RFC 6234, 1262 DOI 10.17487/RFC6234, May 2011, 1263 . 1265 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1266 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1267 May 2017, . 1269 11.2. Informative References 1271 [CZDS] Internet Corporation for Assigned Names and Numbers, 1272 "Centralized Zone Data Service", October 2018, 1273 . 1275 [disk-full-failure] 1276 DENIC, "Background of the Partial Failure of the Name 1277 Service for .de Domains", May 2010, 1278 . 1281 [DnsTools] 1282 NIC Chile Labs, "DNS tools for zone signature (file, 1283 pkcs11-hsm) and validation, and zone digest (ZONEMD)", 1284 April 2020, . 1286 [I-D.ietf-dprive-xfr-over-tls] 1287 Toorop, W., Dickinson, S., Sahib, S., Aras, P., and A. 1288 Mankin, "DNS Zone Transfer-over-TLS", draft-ietf-dprive- 1289 xfr-over-tls-02 (work in progress), July 2020. 1291 [InterNIC] 1292 ICANN, "InterNIC FTP site", May 2018, 1293 . 1295 [ldns-zone-digest] 1296 Verisign, "Implementation of Message Digests for DNS Zones 1297 using the ldns library", July 2018, 1298 . 1300 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 1301 DOI 10.17487/RFC1995, August 1996, 1302 . 1304 [RFC2065] Eastlake 3rd, D. and C. Kaufman, "Domain Name System 1305 Security Extensions", RFC 2065, DOI 10.17487/RFC2065, 1306 January 1997, . 1308 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 1309 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 1310 RFC 2136, DOI 10.17487/RFC2136, April 1997, 1311 . 1313 [RFC2535] Eastlake 3rd, D., "Domain Name System Security 1314 Extensions", RFC 2535, DOI 10.17487/RFC2535, March 1999, 1315 . 1317 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 1318 Wellington, "Secret Key Transaction Authentication for DNS 1319 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 1320 . 1322 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 1323 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 1324 2000, . 1326 [RFC3258] Hardie, T., "Distributing Authoritative Name Servers via 1327 Shared Unicast Addresses", RFC 3258, DOI 10.17487/RFC3258, 1328 April 2002, . 1330 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 1331 Thayer, "OpenPGP Message Format", RFC 4880, 1332 DOI 10.17487/RFC4880, November 2007, 1333 . 1335 [RFC5155] Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS 1336 Security (DNSSEC) Hashed Authenticated Denial of 1337 Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008, 1338 . 1340 [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet 1341 Mail Extensions (S/MIME) Version 3.2 Message 1342 Specification", RFC 5751, DOI 10.17487/RFC5751, January 1343 2010, . 1345 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 1346 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 1347 . 1349 [RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm 1350 Agility and Selecting Mandatory-to-Implement Algorithms", 1351 BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015, 1352 . 1354 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1355 Writing an IANA Considerations Section in RFCs", BCP 26, 1356 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1357 . 1359 [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS 1360 (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, 1361 . 1363 [RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS 1364 Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499, 1365 January 2019, . 1367 [RFC8806] Kumari, W. and P. Hoffman, "Running a Root Server Local to 1368 a Resolver", RFC 8806, DOI 10.17487/RFC8806, June 2020, 1369 . 1371 [RFC8901] Huque, S., Aras, P., Dickinson, J., Vcelak, J., and D. 1372 Blacka, "Multi-Signer DNSSEC Models", RFC 8901, 1373 DOI 10.17487/RFC8901, September 2020, 1374 . 1376 [RootServers] 1377 Root Server Operators, "Root Server Technical Operations", 1378 July 2018, . 1380 [RPZ] Wikipedia, "Response policy zone", May 2020, 1381 . 1384 [ZoneDigestHackathon] 1385 Kerr, S., "Prototype implementation of ZONEMD for the IETF 1386 102 hackathon in Python", July 2018, 1387 . 1389 Appendix A. Example Zones With Digests 1391 This appendix contains example zones with accurate ZONEMD records. 1392 These can be used to verify an implementation of the zone digest 1393 protocol. 1395 A.1. Simple EXAMPLE Zone 1397 Here, the EXAMPLE zone contains an SOA record, NS and glue records, 1398 and a ZONEMD record. 1400 example. 86400 IN SOA ns1 admin 2018031900 ( 1401 1800 900 604800 86400 ) 1402 86400 IN NS ns1 1403 86400 IN NS ns2 1404 86400 IN ZONEMD 2018031900 1 1 ( 1405 c68090d90a7aed71 1406 6bc459f9340e3d7c 1407 1370d4d24b7e2fc3 1408 a1ddc0b9a87153b9 1409 a9713b3c9ae5cc27 1410 777f98b8e730044c ) 1411 ns1 3600 IN A 203.0.113.63 1412 ns2 3600 IN AAAA 2001:db8::63 1414 A.2. Complex EXAMPLE Zone 1416 Here, the EXAMPLE zone contains duplicate RRs, and an occluded RR, 1417 and one out-of-zone RR. 1419 example. 86400 IN SOA ns1 admin 2018031900 ( 1420 1800 900 604800 86400 ) 1421 86400 IN NS ns1 1422 86400 IN NS ns2 1423 86400 IN ZONEMD 2018031900 1 1 ( 1424 31cefb03814f5062 1425 ad12fa951ba0ef5f 1426 8da6ae354a415767 1427 246f7dc932ceb1e7 1428 42a2108f529db6a3 1429 3a11c01493de358d ) 1430 ns1 3600 IN A 203.0.113.63 1431 ns2 3600 IN AAAA 2001:db8::63 1432 occluded.sub 7200 IN TXT "I'm occluded but must be digested" 1433 sub 7200 IN NS ns1 1434 duplicate 300 IN TXT "I must be digested just once" 1435 duplicate 300 IN TXT "I must be digested just once" 1436 foo.test. 555 IN TXT "out-of-zone data must be excluded" 1437 non-apex 900 IN ZONEMD 2018031900 1 1 ( 1438 616c6c6f77656420 1439 6275742069676e6f 1440 7265642e20616c6c 1441 6f77656420627574 1442 2069676e6f726564 1443 2e20616c6c6f7765 ) 1445 A.3. EXAMPLE Zone with multiple digests 1447 Here, the EXAMPLE zone contains multiple ZONEMD records. It has both 1448 SHA384 and SHA512 digests using the SIMPLE scheme. It also includes 1449 ZONEMD records with Scheme and Hash Algorithm values in the private 1450 range (240-254). These additional private-range digests are not 1451 verifiable. 1453 example. 86400 IN SOA ns1 admin 2018031900 ( 1454 1800 900 604800 86400 ) 1455 example. 86400 IN NS ns1.example. 1456 example. 86400 IN NS ns2.example. 1457 example. 86400 IN ZONEMD 2018031900 1 1 ( 1458 62e6cf51b02e54b9 1459 b5f967d547ce4313 1460 6792901f9f88e637 1461 493daaf401c92c27 1462 9dd10f0edb1c56f8 1463 080211f8480ee306 ) 1464 example. 86400 IN ZONEMD 2018031900 1 2 ( 1465 08cfa1115c7b948c 1466 4163a901270395ea 1467 226a930cd2cbcf2f 1468 a9a5e6eb85f37c8a 1469 4e114d884e66f176 1470 eab121cb02db7d65 1471 2e0cc4827e7a3204 1472 f166b47e5613fd27 ) 1473 example. 86400 IN ZONEMD 2018031900 1 240 ( 1474 e2d523f654b9422a 1475 96c5a8f44607bbee ) 1476 example. 86400 IN ZONEMD 2018031900 241 1 ( 1477 e1846540e33a9e41 1478 89792d18d5d131f6 1479 05fc283e ) 1480 ns1.example. 3600 IN A 203.0.113.63 1481 ns2.example. 86400 IN TXT "This example has multiple digests" 1482 ns2.example. 3600 IN AAAA 2001:db8::63 1484 A.4. The URI.ARPA Zone 1486 The URI.ARPA zone retrieved 2018-10-21. Note this sample zone has 1487 (expired) signatures, but no signature for the ZONEMD RR. 1489 ; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr 1490 ; (2 servers found) 1491 ;; global options: +cmd 1492 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1493 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1494 uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 ( 1495 20181028142623 20181007205525 47155 uri.arpa. 1496 eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi 1497 /pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e 1498 HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= ) 1499 uri.arpa. 86400 IN RRSIG NS 8 2 86400 ( 1500 20181028172020 20181007175821 47155 uri.arpa. 1502 ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln 1503 4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF 1504 Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= ) 1505 uri.arpa. 600 IN RRSIG MX 8 2 600 ( 1506 20181028170556 20181007175821 47155 uri.arpa. 1507 e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t 1508 lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK 1509 A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= ) 1510 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1511 20181028152832 20181007175821 15796 uri.arpa. 1512 nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286 1513 XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V 1514 chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR 1515 6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B 1516 dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd 1517 uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk 1518 5R0A1w== ) 1519 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1520 20181028152832 20181007175821 55480 uri.arpa. 1521 lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X 1522 nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV 1523 63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj 1524 2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75 1525 WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R 1526 PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA 1527 1HeBfw== ) 1528 uri.arpa. 3600 IN RRSIG SOA 8 2 3600 ( 1529 20181029114753 20181008222815 47155 uri.arpa. 1530 qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2 1531 Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu 1532 9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= ) 1533 uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA ( 1534 MX RRSIG NSEC DNSKEY ) 1535 uri.arpa. 86400 IN NS a.iana-servers.net. 1536 uri.arpa. 86400 IN NS b.iana-servers.net. 1537 uri.arpa. 86400 IN NS c.iana-servers.net. 1538 uri.arpa. 86400 IN NS ns2.lacnic.net. 1539 uri.arpa. 86400 IN NS sec3.apnic.net. 1540 uri.arpa. 600 IN MX 10 pechora.icann.org. 1541 uri.arpa. 3600 IN DNSKEY 256 3 8 ( 1542 AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK 1543 uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL 1544 Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx 1545 SdJjlH0B ) 1546 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1547 AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY 1548 cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc 1549 3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/ 1550 Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9 1551 iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5 1552 ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt 1553 l3wpbp+Wpm8= ) 1554 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1555 AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR 1556 wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD 1557 FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG 1558 mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU 1559 7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3 1560 e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0 1561 xmJVvNQlwdE= ) 1562 ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1563 20181028080856 20181007175821 47155 uri.arpa. 1564 HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9 1565 jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP 1566 Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= ) 1567 ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1568 20181028103644 20181007205525 47155 uri.arpa. 1569 WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0 1570 9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5 1571 YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= ) 1572 ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR ( 1573 RRSIG NSEC ) 1574 ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1575 "!^ftp://([^:/?#]*).*$!\\1!i" . ) 1576 http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1577 20181029010647 20181007175821 47155 uri.arpa. 1578 U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE 1579 H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+ 1580 ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= ) 1581 http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1582 20181029011815 20181007205525 47155 uri.arpa. 1583 T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F 1584 Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0 1585 RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= ) 1586 http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR ( 1587 RRSIG NSEC ) 1588 http.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1589 "!^http://([^:/?#]*).*$!\\1!i" . ) 1590 mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1591 20181028110727 20181007175821 47155 uri.arpa. 1592 GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/ 1593 IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl 1594 fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= ) 1595 mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1596 20181028141825 20181007205525 47155 uri.arpa. 1597 MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF 1598 j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg 1599 916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= ) 1600 mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR ( 1601 RRSIG NSEC ) 1602 mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1603 "!^mailto:(.*)@(.*)$!\\2!i" . ) 1604 urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1605 20181028123243 20181007175821 47155 uri.arpa. 1606 Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe 1607 UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9 1608 DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= ) 1609 urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1610 20181029071816 20181007205525 47155 uri.arpa. 1611 ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS 1612 D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW 1613 BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= ) 1614 urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG ( 1615 NSEC ) 1616 urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1617 "/urn:([^:]+)/\\1/i" . ) 1618 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1619 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1620 ;; Query time: 66 msec 1621 ;; SERVER: 192.0.32.132#53(192.0.32.132) 1622 ;; WHEN: Sun Oct 21 20:39:28 UTC 2018 1623 ;; XFR size: 34 records (messages 1, bytes 3941) 1624 uri.arpa. 3600 IN ZONEMD 2018100702 1 1 ( 1625 1291b78ddf7669b1a39d014d87626b709b55774c5d7d58fa 1626 dc556439889a10eaf6f11d615900a4f996bd46279514e473 ) 1628 A.5. The ROOT-SERVERS.NET Zone 1630 The ROOT-SERVERS.NET zone retrieved 2018-10-21. 1632 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1633 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1634 root-servers.net. 3600000 IN NS a.root-servers.net. 1635 root-servers.net. 3600000 IN NS b.root-servers.net. 1636 root-servers.net. 3600000 IN NS c.root-servers.net. 1637 root-servers.net. 3600000 IN NS d.root-servers.net. 1638 root-servers.net. 3600000 IN NS e.root-servers.net. 1639 root-servers.net. 3600000 IN NS f.root-servers.net. 1640 root-servers.net. 3600000 IN NS g.root-servers.net. 1641 root-servers.net. 3600000 IN NS h.root-servers.net. 1642 root-servers.net. 3600000 IN NS i.root-servers.net. 1643 root-servers.net. 3600000 IN NS j.root-servers.net. 1644 root-servers.net. 3600000 IN NS k.root-servers.net. 1645 root-servers.net. 3600000 IN NS l.root-servers.net. 1646 root-servers.net. 3600000 IN NS m.root-servers.net. 1647 a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30 1648 a.root-servers.net. 3600000 IN A 198.41.0.4 1649 b.root-servers.net. 3600000 IN MX 20 mail.isi.edu. 1650 b.root-servers.net. 3600000 IN AAAA 2001:500:200::b 1651 b.root-servers.net. 3600000 IN A 199.9.14.201 1652 c.root-servers.net. 3600000 IN AAAA 2001:500:2::c 1653 c.root-servers.net. 3600000 IN A 192.33.4.12 1654 d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d 1655 d.root-servers.net. 3600000 IN A 199.7.91.13 1656 e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e 1657 e.root-servers.net. 3600000 IN A 192.203.230.10 1658 f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f 1659 f.root-servers.net. 3600000 IN A 192.5.5.241 1660 g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d 1661 g.root-servers.net. 3600000 IN A 192.112.36.4 1662 h.root-servers.net. 3600000 IN AAAA 2001:500:1::53 1663 h.root-servers.net. 3600000 IN A 198.97.190.53 1664 i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org. 1665 i.root-servers.net. 3600000 IN AAAA 2001:7fe::53 1666 i.root-servers.net. 3600000 IN A 192.36.148.17 1667 j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30 1668 j.root-servers.net. 3600000 IN A 192.58.128.30 1669 k.root-servers.net. 3600000 IN AAAA 2001:7fd::1 1670 k.root-servers.net. 3600000 IN A 193.0.14.129 1671 l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42 1672 l.root-servers.net. 3600000 IN A 199.7.83.42 1673 m.root-servers.net. 3600000 IN AAAA 2001:dc3::35 1674 m.root-servers.net. 3600000 IN A 202.12.27.33 1675 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1676 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1677 root-servers.net. 3600000 IN ZONEMD 2018091100 1 1 ( 1678 f1ca0ccd91bd5573d9f431c00ee0101b2545c97602be0a97 1679 8a3b11dbfc1c776d5b3e86ae3d973d6b5349ba7f04340f79 ) 1681 Appendix B. Implementation Status 1683 RFC Editor: Please retain this section upon publication. 1685 This section records the status of known implementations of the 1686 protocol defined by this specification at the time of publication, 1687 and is inspired by the concepts described in RFC7942. 1689 Please note that the listing of any individual implementation here 1690 does not imply endorsement by the IETF. Furthermore, no effort has 1691 been spent to verify the information presented here that was supplied 1692 by IETF contributors. This is not intended as, and must not be 1693 construed to be, a catalog of available implementations or their 1694 features. Readers are advised to note that other implementations may 1695 exist. 1697 B.1. Authors' Implementation 1699 The authors have an open source implementation in C, using the ldns 1700 library [ldns-zone-digest]. This implementation is able to perform 1701 the following functions: 1703 o Read an input zone and output a zone with the ZONEMD placeholder. 1705 o Compute zone digest over signed zone and update the ZONEMD record. 1707 o Re-compute DNSSEC signature over the ZONEMD record. 1709 o Verify the zone digest from an input zone. 1711 This implementation does not: 1713 o Perform DNSSEC validation of the ZONEMD record during 1714 verification. 1716 B.2. Shane Kerr's Implementation 1718 Shane Kerr wrote an implementation of this specification during the 1719 IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in 1720 Python and is able to perform the following functions: 1722 o Read an input zone and output a zone with ZONEMD record. 1724 o Verify the zone digest from an input zone. 1726 o Output the ZONEMD record in its defined presentation format. 1728 This implementation does not: 1730 o Re-compute DNSSEC signature over the ZONEMD record. 1732 o Perform DNSSEC validation of the ZONEMD record. 1734 B.3. NIC Chile Labs Implementation 1736 NIC Chile Labs wrote an implementation of this specification as part 1737 of "dns-tools" suite [DnsTools], which besides digesting, can also 1738 sign and verify zones. This implementation is in Go and is able to 1739 perform the following functions: 1741 o Compute zone digest over signed zone and update the ZONEMD record. 1743 o Verify the zone digest from an input zone. 1745 o Perform DNSSEC validation of the ZONEMD record during 1746 verification. 1748 o Re-compute DNSSEC signature over the ZONEMD record. 1750 Authors' Addresses 1752 Duane Wessels 1753 Verisign 1754 12061 Bluemont Way 1755 Reston, VA 20190 1757 Phone: +1 703 948-3200 1758 Email: dwessels@verisign.com 1759 URI: https://verisign.com 1761 Piet Barber 1762 Verisign 1763 12061 Bluemont Way 1764 Reston, VA 20190 1766 Phone: +1 703 948-3200 1767 Email: pbarber@verisign.com 1768 URI: https://verisign.com 1770 Matt Weinberg 1771 Amazon 1773 Email: matweinb@amazon.com 1774 URI: https://amazon.com 1775 Warren Kumari 1776 Google 1777 1600 Amphitheatre Parkway 1778 Mountain View, CA 94043 1780 Email: warren@kumari.net 1782 Wes Hardaker 1783 USC/ISI 1784 P.O. Box 382 1785 Davis, CA 95617 1787 Email: ietf@hardakers.net