idnits 2.17.1 draft-ietf-dnsop-dns-zone-digest-10.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- == There are 14 instances of lines with non-RFC6890-compliant IPv4 addresses in the document. If these are example addresses, they should be changed. == There are 1 instance of lines with non-RFC3849-compliant IPv6 addresses in the document. If these are example addresses, they should be changed. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (September 21, 2020) is 1313 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 6234 -- Obsolete informational reference (is this intentional?): RFC 2065 (Obsoleted by RFC 2535) -- Obsolete informational reference (is this intentional?): RFC 2535 (Obsoleted by RFC 4033, RFC 4034, RFC 4035) -- Obsolete informational reference (is this intentional?): RFC 2845 (Obsoleted by RFC 8945) -- Obsolete informational reference (is this intentional?): RFC 5751 (Obsoleted by RFC 8551) -- Obsolete informational reference (is this intentional?): RFC 8499 (Obsoleted by RFC 9499) Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 6 comments (--). 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: March 25, 2021 M. Weinberg 6 Amazon 7 W. Kumari 8 Google 9 W. Hardaker 10 USC/ISI 11 September 21, 2020 13 Message Digest for DNS Zones 14 draft-ietf-dnsop-dns-zone-digest-10 16 Abstract 18 This document describes a protocol and new DNS Resource Record that 19 provides a cryptographic message digest over DNS zone data. The 20 ZONEMD Resource Record conveys the digest data in the zone itself. 21 When a zone publisher includes a ZONEMD record, recipients can verify 22 the zone contents for accuracy and completeness. This provides 23 assurance that received zone data matches published data, regardless 24 of how the zone data has been transmitted and received. 26 ZONEMD does not replace DNSSEC. Whereas DNSSEC protects individual 27 RRSets (DNS data with fine granularity), ZONEMD protects a zone's 28 data as a whole, whether consumed by authoritative name servers, 29 recursive name servers, or any other applications. 31 As specified herein, ZONEMD is impractical for large, dynamic zones 32 due to the time and resources required for digest calculation. 33 However, The ZONEMD record is extensible so that new digest schemes 34 may be added in the future to support large, dynamic zones. 36 Status of This Memo 38 This Internet-Draft is submitted in full conformance with the 39 provisions of BCP 78 and BCP 79. 41 Internet-Drafts are working documents of the Internet Engineering 42 Task Force (IETF). Note that other groups may also distribute 43 working documents as Internet-Drafts. The list of current Internet- 44 Drafts is at https://datatracker.ietf.org/drafts/current/. 46 Internet-Drafts are draft documents valid for a maximum of six months 47 and may be updated, replaced, or obsoleted by other documents at any 48 time. It is inappropriate to use Internet-Drafts as reference 49 material or to cite them other than as "work in progress." 51 This Internet-Draft will expire on March 25, 2021. 53 Copyright Notice 55 Copyright (c) 2020 IETF Trust and the persons identified as the 56 document authors. All rights reserved. 58 This document is subject to BCP 78 and the IETF Trust's Legal 59 Provisions Relating to IETF Documents 60 (https://trustee.ietf.org/license-info) in effect on the date of 61 publication of this document. Please review these documents 62 carefully, as they describe your rights and restrictions with respect 63 to this document. Code Components extracted from this document must 64 include Simplified BSD License text as described in Section 4.e of 65 the Trust Legal Provisions and are provided without warranty as 66 described in the Simplified BSD License. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 71 1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4 72 1.2. Alternative Approaches . . . . . . . . . . . . . . . . . 4 73 1.3. Design Overview . . . . . . . . . . . . . . . . . . . . . 6 74 1.4. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . 6 75 1.4.1. Root Zone . . . . . . . . . . . . . . . . . . . . . . 6 76 1.4.2. Providers, Secondaries, and Anycast . . . . . . . . . 6 77 1.4.3. Response Policy Zones . . . . . . . . . . . . . . . . 7 78 1.4.4. Centralized Zone Data Service . . . . . . . . . . . . 7 79 1.4.5. General Purpose Comparison Check . . . . . . . . . . 7 80 1.5. Terminology . . . . . . . . . . . . . . . . . . . . . . . 7 81 2. The ZONEMD Resource Record . . . . . . . . . . . . . . . . . 7 82 2.1. Non-apex ZONEMD Records . . . . . . . . . . . . . . . . . 8 83 2.2. ZONEMD RDATA Wire Format . . . . . . . . . . . . . . . . 8 84 2.2.1. The Serial Field . . . . . . . . . . . . . . . . . . 8 85 2.2.2. The Scheme Field . . . . . . . . . . . . . . . . . . 9 86 2.2.3. The Hash Algorithm Field . . . . . . . . . . . . . . 9 87 2.2.4. The Digest Field . . . . . . . . . . . . . . . . . . 9 88 2.3. ZONEMD Presentation Format . . . . . . . . . . . . . . . 9 89 2.4. ZONEMD Example . . . . . . . . . . . . . . . . . . . . . 10 90 3. Calculating the Digest . . . . . . . . . . . . . . . . . . . 10 91 3.1. Add ZONEMD Placeholder . . . . . . . . . . . . . . . . . 10 92 3.2. Optionally Sign the Zone . . . . . . . . . . . . . . . . 11 93 3.3. Scheme-Specific Processing . . . . . . . . . . . . . . . 11 94 3.3.1. The SIMPLE Scheme . . . . . . . . . . . . . . . . . . 11 95 3.3.1.1. SIMPLE Scheme Inclusion/Exclusion Rules . . . . . 11 96 3.3.1.2. SIMPLE Scheme Digest Calculation . . . . . . . . 12 97 3.4. Update ZONEMD RR . . . . . . . . . . . . . . . . . . . . 12 98 4. Verifying Zone Digest . . . . . . . . . . . . . . . . . . . . 12 99 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 100 5.1. ZONEMD RRtype . . . . . . . . . . . . . . . . . . . . . . 14 101 5.2. ZONEMD Scheme . . . . . . . . . . . . . . . . . . . . . . 14 102 5.3. ZONEMD Hash Algorithm . . . . . . . . . . . . . . . . . . 14 103 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15 104 6.1. Attacks Against the Zone Digest . . . . . . . . . . . . . 15 105 6.2. DNSSESC Timing Considerations . . . . . . . . . . . . . . 16 106 6.3. Attacks Utilizing ZONEMD Queries . . . . . . . . . . . . 16 107 6.4. Resilience and Fragility . . . . . . . . . . . . . . . . 16 108 7. Performance Considerations . . . . . . . . . . . . . . . . . 17 109 7.1. SIMPLE SHA384 . . . . . . . . . . . . . . . . . . . . . . 17 110 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18 111 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 112 10. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 18 113 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 114 11.1. Normative References . . . . . . . . . . . . . . . . . . 24 115 11.2. Informative References . . . . . . . . . . . . . . . . . 24 116 Appendix A. Example Zones With Digests . . . . . . . . . . . . . 27 117 A.1. Simple EXAMPLE Zone . . . . . . . . . . . . . . . . . . . 27 118 A.2. Complex EXAMPLE Zone . . . . . . . . . . . . . . . . . . 27 119 A.3. EXAMPLE Zone with multiple digests . . . . . . . . . . . 28 120 A.4. The URI.ARPA Zone . . . . . . . . . . . . . . . . . . . . 29 121 A.5. The ROOT-SERVERS.NET Zone . . . . . . . . . . . . . . . . 32 122 Appendix B. Implementation Status . . . . . . . . . . . . . . . 34 123 B.1. Authors' Implementation . . . . . . . . . . . . . . . . . 34 124 B.2. Shane Kerr's Implementation . . . . . . . . . . . . . . . 34 125 B.3. NIC Chile Labs Implementation . . . . . . . . . . . . . . 35 126 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 35 128 1. Introduction 130 In the DNS, a zone is the collection of authoritative resource 131 records (RRs) sharing a common origin ([RFC8499]). Zones are often 132 stored as files in the so-called master file format [RFC1034]. Zones 133 are generally distributed among name servers using the AXFR (zone 134 transfer [RFC5936]), and IXFR (incremental zone transfer [RFC1995]) 135 protocols. They can also be distributed outside of the DNS, with any 136 file transfer protocol such as FTP, HTTP, and rsync, or even as email 137 attachments. Currently there is no standard way to verify the 138 authenticity of a stand-alone zone. 140 This document specifies an RR type that provides a cryptographic 141 message digest of the data in a zone. It allows a receiver of the 142 zone to verify the zone's integrity, and when used in combination 143 with DNSSEC, its authenticity. The digest RR is a part of the zone 144 itself, allowing verification of the zone, no matter how it is 145 transmitted. The digest uses the wire format of zone data in a 146 canonical ordering. Thus, it is independent of presentation format, 147 such as whitespace, capitalization, and comments. 149 This specification is OPTIONAL to implement by both publishers and 150 consumers of zone data. 152 DNSSEC provides three strong security guarantees relevant to this 153 protocol: 155 1. whether or not to expect DNSSEC records in the zone, 157 2. whether or not to expect a ZONEMD record in a signed zone, and 159 3. whether or not the ZONEMD record has been altered since it was 160 signed. 162 1.1. Motivation 164 The motivation for this protocol enhancement is the desire to verify 165 the authenticity of a stand-alone zone, regardless of how it is 166 transmitted. A consumer of zone data should be able to verify that 167 the data is as-published by the zone operator. 169 1.2. Alternative Approaches 171 One approach to preventing data tampering and corruption is to secure 172 the distribution channel. The DNS has a number of features that are 173 already used for channel security. Perhaps the most widely used is 174 DNS transaction signatures (TSIG [RFC2845]). TSIG uses shared secret 175 keys and a message digest to protect individual query and response 176 messages. It is generally used to authenticate and validate UPDATE 177 [RFC2136], AXFR [RFC5936], and IXFR [RFC1995] messages. 179 DNS Request and Transaction Signatures (SIG(0) [RFC2931]) is another 180 protocol extension that authenticates individual DNS transactions. 181 Whereas SIG records normally cover specific RR types, SIG(0) is used 182 to sign an entire DNS message. Unlike TSIG, SIG(0) uses public key 183 cryptography rather than shared secrets. 185 The Transport Layer Security protocol suite also provides channel 186 security. One can easily imagine the distribution of zones over 187 HTTPS-enabled web servers, as well as DNS-over-HTTPS [RFC8484], and 188 perhaps even a future version of DNS-over-TLS ([RFC7858]). 190 Unfortunately, the protections provided by these channel security 191 techniques are (in practice) ephemeral and are not retained after the 192 data transfer is complete. They ensure that the client receives the 193 data from the expected server, and that the data sent by the server 194 is not modified during transmission. However, they do not guarantee 195 that the server transmits the data as originally published, and do 196 not provide any methods to verify data that is read after 197 transmission is complete. For example, a name server loading saved 198 zone data upon restart cannot guarantee that the on-disk data has not 199 been modified. Such modification could be the result of an 200 accidental corruption of the file, or perhaps an incompletely saved 201 file [disk-full-failure]. For these reasons, it is preferable to 202 secure the data itself. 204 Why not simply rely on DNSSEC, which provides certain data security 205 guarantees? For zones that are signed, a recipient could validate 206 all of the signed RRSets. Additionally, denial-of-existence records 207 prove that RRSets have not been added or removed. However, 208 delegations (non-apex NS records) are not signed by DNSSEC, and 209 neither are any glue records. ZONEMD protects the integrity of 210 delegation, glue, and other records that are not otherwise covered by 211 DNSSEC. Furthermore, zones that employ NSEC3 with opt-out are 212 susceptible to the removal or addition of names between the signed 213 nodes. Whereas DNSSEC is primarily protects consumers of DNS 214 response messages, this protocol protects consumers of zones. 216 There are existing tools and protocols that provide data security, 217 such as OpenPGP [RFC4880] and S/MIME [RFC5751]. In fact, the 218 internic.net site publishes PGP signatures alongside the root zone 219 and other files available there. However, this is a detached 220 signature with no strong association to the corresponding zone file 221 other than its timestamp. Non-detached signatures are, of course, 222 possible, but these necessarily change the format of the file being 223 distributed; a zone signed with OpenPGP or S/MIME no longer looks 224 like a DNS zone and could not directly be loaded into a name server. 225 Once loaded the signature data is lost, so it cannot be further 226 propagated. 228 It seems the desire for data security in DNS zones was envisioned as 229 far back as 1997. [RFC2065] is an obsoleted specification of the 230 first generation DNSSEC Security Extensions. It describes a zone 231 transfer signature, identified as the AXFR SIG, which is similar to 232 the technique proposed by this document. That is, it proposes 233 ordering all (signed) RRSets in a zone, hashing their contents, and 234 then signing the zone hash. The AXFR SIG is described only for use 235 during zone transfers. It did not postulate the need to validate 236 zone data distributed outside of the DNS. Furthermore, its 237 successor, [RFC2535], omits the AXFR SIG, while at the same time 238 introducing an IXFR SIG. 240 1.3. Design Overview 242 This document specifies a new Resource Record type to convey a 243 message digest of the content of a zone. The digest is calculated at 244 the time of zone publication. If the zone is signed with DNSSEC, any 245 modifications of the digest can be detected. The procedures for 246 digest calculation and DNSSEC signing are similar. Both require data 247 to be processed in a well-defined order and format. It may be 248 possible to perform DNSSEC signing and digest calculation in 249 parallel. 251 The zone digest is designed to be used on zones that have infrequent 252 updates. As specified herein, the digest is re-calculated over the 253 entire zone content each time. This specification does not provide 254 an efficient mechanism for updating the digest on incremental updates 255 of zone data. It is, however, extensible so future schemes to 256 support incremental zone digest algorithms (e.g. using Merkle trees) 257 can be accommodated. 259 It is expected that verification of a zone digest will be implemented 260 in name server software. That is, a name server can verify the zone 261 data it was given and refuse to serve a zone which fails 262 verification. For signed zones, the name server needs a trust anchor 263 to perform DNSSEC validation. For signed non-root zones, the name 264 server may need to send queries to validate a chain of trust. Digest 265 verification could also be performed externally. 267 1.4. Use Cases 269 1.4.1. Root Zone 271 The root zone [InterNIC] is one of the most widely distributed DNS 272 zone on the Internet, served by more than 1000 separate instances 273 [RootServers] at the time of this writing. Additionally, many 274 organizations configure their own name servers to serve the root zone 275 locally. Reasons for doing so include privacy and reduced access 276 time. [RFC8806] describes one way to do this. As the root zone 277 spreads beyond its traditional deployment boundaries, the 278 verification of the completeness of the zone contents becomes more 279 important. 281 1.4.2. Providers, Secondaries, and Anycast 283 Since its very early days, the developers of the DNS recognized the 284 importance of secondary name servers and service diversity. However, 285 modern DNS service has complex provisioning which includes multiple 286 third-party providers and hundreds of anycast instances. Instead of 287 a simple primary-to-secondary zone distribution system, today it is 288 possible to have multiple levels, multiple parties, and multiple 289 protocols involved in the distribution of zone data. This complexity 290 introduces new places for problems to arise. The zone digest 291 protects the integrity of data that flows through such systems. 293 1.4.3. Response Policy Zones 295 DNS Response Policy Zones is "a method of expressing DNS response 296 policy information inside specially constructed DNS zones..." [RPZ]. 297 A number of companies provide RPZ feeds, which are consumed by name 298 server and firewall products. While RPZ zones can be signed with 299 DNSSEC, the data is not queried directly, and would not be subject to 300 DNSSEC validation. 302 1.4.4. Centralized Zone Data Service 304 ICANN operates the Centralized Zone Data Service [CZDS], which is a 305 repository of top-level domain zone files. Users that have been 306 granted access are then able to download zone data. Adding a zone 307 digest to these would provide CZDS users with assurances that the 308 data has not been modified. ZONEMD could be added to CZDS zone data 309 independently of the zone served by production name servers. 311 1.4.5. General Purpose Comparison Check 313 Since the zone digest calculation does not depend on presentation 314 format, it could be used to compare multiple copies of a zone 315 received from different sources, or copies generated by different 316 processes. 318 1.5. Terminology 320 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 321 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 322 "OPTIONAL" in this document are to be interpreted as described in BCP 323 14 [RFC2119] [RFC8174] when, and only when, they appear in all 324 capitals, as shown here. 326 The terms Private Use, Reserved, Unassigned, and Specification 327 Required are to be interpreted as defined in [RFC8126]. 329 2. The ZONEMD Resource Record 331 This section describes the ZONEMD Resource Record, including its 332 fields, wire format, and presentation format. The Type value for the 333 ZONEMD RR is 63. The ZONEMD RR is class independent. The RDATA of 334 the resource record consists of four fields: Serial, Scheme, Hash 335 Algorithm, and Digest. 337 A zone MAY contain multiple ZONEMD RRs to support algorithm agility 338 [RFC7696] and rollovers. When multiple ZONEMD RRs are present, each 339 must specify a unique Scheme and Hash Algorithm tuple. It is 340 recommended that a zone include only one ZONEMD RR, unless the zone 341 publisher is in the process of transitioning to a new Scheme or Hash 342 Algorithm. 344 2.1. Non-apex ZONEMD Records 346 This document specifies ZONEMD RRs located at the zone apex. Non- 347 apex ZONEMD RRs are not forbidden, but have no meaning in this 348 specification. Non-apex ZONEMD RRs MUST NOT be used for 349 verification. 351 During digest calculation, non-apex ZONEMD RRs are treated as 352 ordinary RRs. They are digested as-is and the RR is not replaced by 353 a placeholder RR. 355 Unless explicitly stated otherwise, "ZONEMD" always refers to apex 356 records throughout this document. 358 2.2. ZONEMD RDATA Wire Format 360 The ZONEMD RDATA wire format is encoded as follows: 362 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 363 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 1 364 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 365 | Serial | 366 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 367 | Scheme |Hash Algorithm | | 368 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 369 | Digest | 370 / / 371 / / 372 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 374 2.2.1. The Serial Field 376 The Serial field is a 32-bit unsigned integer in network byte order. 377 It is the serial number from the zone's SOA record ([RFC1035] section 378 3.3.13) for which the zone digest was generated. 380 It is included here in order to make DNS response messages of type 381 ZONEMD meaningful. Without the serial number, a stand-alone ZONEMD 382 digest has no association to any particular instance of a zone. 384 2.2.2. The Scheme Field 386 The Scheme field is an 8-bit unsigned integer that identifies the 387 methods by which data is collated and presented as input to the 388 hashing function. 390 Herein, SIMPLE, with value 1, is the only standardized Scheme defined 391 for ZONEMD records and it MUST be implemented. The Scheme registry 392 is further described in Section 5. 394 Scheme values 240-254 are allocated for Private Use. 396 2.2.3. The Hash Algorithm Field 398 The Hash Algorithm field is an 8-bit unsigned integer that identifies 399 the cryptographic hash algorithm used to construct the digest. 401 Herein, SHA384 [RFC6234], with value 1, is the only standardized Hash 402 Algorithm defined for ZONEMD records that MUST be implemented. When 403 SHA384 is used, the size of the Digest field is 48 octets. 405 SHA512 [RFC6234], with Hash Algorithm value 2, is also defined for 406 ZONEMD records, and SHOULD be implemented. When SHA512 is used, the 407 size of the Digest field is 64 octets. 409 Hash Algorithm values 240-254 are allocated for Private Use. 411 The Hash Algorithm registry is further described in Section 5. 413 2.2.4. The Digest Field 415 The Digest field is a variable-length sequence of octets containing 416 the output of the hash algorithm. The Digest field MUST NOT be 417 shorter than 12 octets. The length of the Digest field is determined 418 by deducting the fixed size of the Serial, Scheme, and Hash Algorithm 419 fields from the RDATA size in the ZONEMD RR header. Section 3 420 describes how to calculate the digest for a zone. Section 4 421 describes how to use the digest to verify the contents of a zone. 423 2.3. ZONEMD Presentation Format 425 The presentation format of the RDATA portion is as follows: 427 The Serial field is represented as an unsigned decimal integer. 429 The Scheme field is represented as an unsigned decimal integer. 431 The Hash Algorithm field is represented as an unsigned decimal 432 integer. 434 The Digest is represented as a sequence of case-insensitive 435 hexadecimal digits. Whitespace is allowed within the hexadecimal 436 text. 438 2.4. ZONEMD Example 440 The following example shows a ZONEMD RR in presentation format: 442 example.com. 86400 IN ZONEMD 2018031500 1 1 ( 443 FEBE3D4CE2EC2FFA4BA99D46CD69D6D29711E55217057BEE 444 7EB1A7B641A47BA7FED2DD5B97AE499FAFA4F22C6BD647DE ) 446 3. Calculating the Digest 448 3.1. Add ZONEMD Placeholder 450 In preparation for calculating the zone digest, any existing ZONEMD 451 records (and covering RRSIGs) at the zone apex are first deleted. 453 Prior to calculation of the digest, and prior to signing with DNSSEC, 454 one or more placeholder ZONEMD records are added to the zone apex. 455 This ensures that denial-of-existence (NSEC, NSEC3) records are 456 created correctly if the zone is signed with DNSSEC. If placeholders 457 were not added prior to signing, the later addition of ZONEMD records 458 would also require updating the Type Bit Maps field of any apex NSEC/ 459 NSEC3 RRs, which then invalidates the calculated digest value. 461 When multiple ZONEMD RRs are published in the zone, e.g., during an 462 algorithm rollover, each MUST specify a unique Scheme and Hash 463 Algorithm tuple. 465 It is RECOMMENDED that the TTL of the ZONEMD record match the TTL of 466 the SOA. 468 In the placeholder record, the Serial field is set to the current SOA 469 Serial. The Scheme field is set to the value for the chosen 470 collation scheme. The Hash Algorithm field is set to the value for 471 the chosen hash algorithm. Since ZONEMD records are excluded from 472 digest calculation, the value of the Digest field does not matter at 473 this point in the process. 475 3.2. Optionally Sign the Zone 477 Following addition of placeholder records, the zone may be signed 478 with DNSSEC. When the digest calculation is complete, and the ZONEMD 479 record is updated, the signature(s) for the ZONEMD RRSet MUST be 480 recalculated and updated as well. Therefore, the signer is not 481 required to calculate a signature over the placeholder record at this 482 step in the process, but it is harmless to do so. 484 3.3. Scheme-Specific Processing 486 Herein, only the SIMPLE collation scheme is defined. Additional 487 schemes may be defined in future updates to this document. 489 3.3.1. The SIMPLE Scheme 491 For the SIMPLE scheme, the digest is calculated over the zone as a 492 whole. This means that a change to a single RR in the zone requires 493 iterating over all RRs in the zone to recalculate the digest. SIMPLE 494 is a good choice for zones that are small and/or stable, but probably 495 not good for zones that are large and/or dynamic. 497 Calculation of a zone digest REQUIRES RRs to be processed in a 498 consistent format and ordering. This specification uses DNSSEC's 499 canonical on-the-wire RR format (without name compression) and 500 ordering as specified in Sections 6.1, 6.2, and 6.3 of [RFC4034] with 501 the additional provision that RRSets having the same owner name MUST 502 be numerically ordered, in ascending order, by their numeric RR TYPE. 504 3.3.1.1. SIMPLE Scheme Inclusion/Exclusion Rules 506 When iterating over records in the zone, the following inclusion/ 507 exclusion rules apply: 509 o All records in the zone, including glue records, MUST be included. 511 o Occluded data ([RFC5936] Section 3.5) MUST be included. 513 o If there are duplicate RRs with equal owner, class, type, and 514 RDATA, only one instance is included ([RFC4034] Section 6.3), and 515 the duplicates MUST be omitted. 517 o The placeholder ZONEMD RR(s) MUST NOT be included. 519 o If the zone is signed, DNSSEC RRs MUST be included, except: 521 o The RRSIG covering ZONEMD MUST NOT be included because the RRSIG 522 will be updated after all digests have been calculated. 524 3.3.1.2. SIMPLE Scheme Digest Calculation 526 A zone digest using the SIMPLE scheme is calculated by concatenating 527 all RRs in the zone, in the format and order described in 528 Section 3.3.1 subject to the inclusion/exclusion rules described in 529 Section 3.3.1.1, and then applying the chosen hash algorithm: 531 digest = hash( RR(1) | RR(2) | RR(3) | ... ) 533 where "|" denotes concatenation. 535 3.4. Update ZONEMD RR 537 The calculated zone digest is inserted into the placeholder ZONEMD 538 RR. Repeat for each digest if multiple digests are to be published. 540 If the zone is signed with DNSSEC, the RRSIG record(s) covering the 541 ZONEMD RRSet MUST then be added or updated. Because the ZONEMD 542 placeholder was added prior to signing, the zone will already have 543 the appropriate denial-of-existence (NSEC, NSEC3) records. 545 Some DNSSEC implementations (especially "online signing") might 546 update the SOA serial number whenever a new signature is made. To 547 preserve the calculated digest, generation of a ZONEMD signature MUST 548 NOT also result in a change to the SOA serial number. The ZONEMD RR 549 and the matching SOA MUST be published at the same time. 551 4. Verifying Zone Digest 553 The recipient of a zone that has a ZONEMD RR verifies the zone by 554 calculating the digest as follows. If multiple ZONEMD RRs are 555 present in the zone, e.g., during an algorithm rollover, a match 556 using any one of the recipient's supported Schemes and Hash 557 Algorithms is sufficient to verify the zone. The verifier MAY ignore 558 a ZONEMD RR if its Scheme and Hash Algorithm violates local policy. 560 1. The verifier MUST first determine whether or not to expect DNSSEC 561 records in the zone. This is done by examining locally 562 configured trust anchors, or querying for (and validating) DS RRs 563 in the parent zone. For zones that are provably insecure, or if 564 DNSSEC validation is not performed, digest verification continues 565 at step 4 below. 567 2. For zones that are provably secure, the existence of the apex 568 ZONEMD record MUST be verified. If the ZONEMD record provably 569 does not exist, digest verification cannot occur. If the ZONEMD 570 record does provably exist, but is not found in the zone, digest 571 verification MUST NOT be considered successful. 573 3. For zones that are provably secure, the SOA and ZONEMD RRSets 574 MUST have valid signatures, chaining up to a trust anchor. If 575 DNSSEC validation of the SOA or ZONEMD records fails, digest 576 verification MUST NOT be considered successful. 578 4. When multiple ZONEMD RRs are present, each MUST specify a unique 579 Scheme and Hash Algorithm tuple. If the ZONEMD RRSet contains 580 more than one RR with the same Scheme and Hash Algorithm, digest 581 verification for those ZONEMD RRs MUST NOT be considered 582 successful. 584 5. Loop over all apex ZONEMD RRs and perform the following steps: 586 A. The SOA Serial field MUST exactly match the ZONEMD Serial 587 field. If the fields do not match, digest verification MUST 588 NOT be considered successful with this ZONEMD RR. 590 B. The Scheme field MUST be checked. If the verifier does not 591 support the given scheme, verification MUST NOT be considered 592 successful with this ZONEMD RR and it SHOULD report that the 593 RR's digest could not be verified due to an unsupported 594 scheme. 596 C. The Hash Algorithm field MUST be checked. If the verifier 597 does not support the given hash algorithm, verification MUST 598 NOT be considered successful with this ZONEMD RR and it 599 SHOULD report that the RR's digest could not be verified due 600 to an unsupported algorithm. 602 D. The Digest field size MUST be checked. If the size of the 603 given Digest field is smaller than 12 octets, or if the size 604 is not equal to the size expected for the corresponding Hash 605 Algorithm, verification MUST NOT be considered successful 606 with this ZONEMD RR and the verifier SHOULD report that the 607 RR's digest could not be verified to to an incorrect digest 608 length. 610 E. The zone digest is computed over the zone data as described 611 in Section 3.3, using the Scheme and Hash Algorithm for the 612 current ZONEMD RR. 614 F. The computed digest is compared to the received digest. If 615 the two digest values match, verification is considered 616 successful. Otherwise, verification MUST NOT be considered 617 successful for this ZONEMD RR. 619 5. IANA Considerations 621 5.1. ZONEMD RRtype 623 This document defines a new DNS RR type, ZONEMD, whose value 63 has 624 been allocated by IANA from the "Resource Record (RR) TYPEs" 625 subregistry of the "Domain Name System (DNS) Parameters" registry: 627 Type: ZONEMD 629 Value: 63 631 Meaning: Message Digest Over Zone Data 633 Reference: [this document] 635 5.2. ZONEMD Scheme 637 IANA is requested to create a new registry on the "Domain Name System 638 (DNS) Parameters" web page as follows: 640 Registry Name: ZONEMD Schemes 642 Registration Procedure: Specification Required 644 Reference: [this document] 646 +---------+---------------+----------+------------------+-----------+ 647 | Value | Description | Mnemonic | Implementation | Reference | 648 | | | | Requirement | | 649 +---------+---------------+----------+------------------+-----------+ 650 | 0 | Reserved | | | | 651 | 1 | Simple ZONEMD | SIMPLE | MUST | [this | 652 | | collation | | | document] | 653 | 2-239 | Unassigned | | | | 654 | 240-254 | Private Use | N/A | N/A | [this | 655 | | | | | document] | 656 | 255 | Reserved | | | | 657 +---------+---------------+----------+------------------+-----------+ 659 Table 1: ZONEMD Scheme Registry 661 5.3. ZONEMD Hash Algorithm 663 IANA is requested to create a new registry on the "Domain Name System 664 (DNS) Parameters" web page as follows: 666 Registry Name: ZONEMD Hash Algorithms 667 Registration Procedure: Specification Required 669 Reference: [this document] 671 +---------+-------------+----------+-------------------+------------+ 672 | Value | Description | Mnemonic | Implementation | Reference | 673 | | | | Requirement | | 674 +---------+-------------+----------+-------------------+------------+ 675 | 0 | Reserved | | | | 676 | 1 | SHA-384 | SHA384 | MUST | [this | 677 | | | | | document] | 678 | 2 | SHA-512 | SHA512 | SHOULD | [this | 679 | | | | | document] | 680 | 3-239 | Unassigned | | | | 681 | 240-254 | Private Use | N/A | N/A | [his | 682 | | | | | document] | 683 | 255 | Reserved | | | | 684 +---------+-------------+----------+-------------------+------------+ 686 Table 2: ZONEMD Hash Algorithm Registry 688 The IANA policy for assigning new values to the ZONEMD Hash Algorithm 689 registry shall be Specification Required. 691 6. Security Considerations 693 6.1. Attacks Against the Zone Digest 695 The zone digest allows the recipient of a zone to verify its 696 integrity. In conjunction with DNSSEC, the recipient can 697 authenticate that it is as published by the zone originator. 699 An attacker, whose goal is to modify zone content before it is used 700 by the victim, may consider a number of different approaches. 702 The attacker might perform a downgrade attack to an unsigned zone. 703 This is why Section 4 talks about determining whether or not to 704 expect DNSSEC signatures for the zone in step 1. 706 The attacker might perform a downgrade attack by removing one or more 707 ZONEMD records. Such a removal is detectable only with DNSSEC 708 validation and is why Section 4 talks about checking denial-of- 709 existence proofs in step 2 and signature validation in step 3. 711 The attacker might alter the Scheme, Hash Algorithm, or Digest fields 712 of the ZONEMD record. Such modifications are detectable only with 713 DNSSEC validation. 715 6.2. DNSSESC Timing Considerations 717 As with all DNSSEC signatures, the ability to perform signature 718 validation of a ZONEMD record is limited in time. If the DS 719 record(s) or trust anchors for the zone to be verified are no longer 720 available, the recipient cannot validate the ZONEMD RRSet. This 721 could happen even if the ZONEMD signature is still current (not 722 expired), since the zone's DS record(s) may have been withdrawn 723 following a KSK rollover. 725 For zones where it may be important to validate a ZONEMD RRSet 726 through its entire signature validity period, the zone operator 727 should ensure that KSK rollover timing takes this into consideration. 729 6.3. Attacks Utilizing ZONEMD Queries 731 Nothing in this specification prevents clients from making, and 732 servers from responding to, ZONEMD queries. Servers SHOULD NOT 733 calculate zone digests dynamically (for each query) as this can be 734 used as a CPU resource exhaustion attack. 736 ZONEMD responses could be used in a distributed denial-of-service 737 amplification attack. The ZONEMD RR is moderately sized, much like 738 the DS RR. A single ZONEMD RR contributes approximately 40 to 65 739 octets to a DNS response, for digest types defined herein. Other RR 740 types, such as DNSKEY, can result in larger amplification effects. 742 6.4. Resilience and Fragility 744 ZONEMD is used to detect incomplete or corrupted zone data prior to 745 its use, thereby increasing resilience by not using corrupt data, but 746 also introduces some denial-of-service fragility by making good data 747 in a zone unavailable if some other data is missing or corrupt. 748 Publishers and consumers of zones containing ZONEMD records should be 749 aware of these tradeoffs. While the intention is to secure the zone 750 data, misconfigurations or implementation bugs are generally 751 indistinguishable from intentional tampering, and could lead to 752 service failures when verification is performed automatically. 754 Zone publishers may want to deploy ZONEMD gradually, perhaps by 755 utilizing one of the private use hash algorithms listed in 756 Section 5.3. Similarly, recipients may want to initially configure 757 verification failures only as a warning, and later as an error after 758 gaining experience and confidence with the feature. 760 7. Performance Considerations 762 This section is provided to make zone publishers aware of the 763 performance requirements and implications of including ZONEMD RRs in 764 a zone. 766 7.1. SIMPLE SHA384 768 As mentioned previously, the SIMPLE scheme may be impractical for use 769 in zones that are either large or highly dynamic. Zone publishers 770 should carefully consider the use of ZONEMD in such zones, since it 771 might cause consumers of zone data (e.g., secondary name servers) to 772 expend resources on digest calculation. For such use cases, it is 773 recommended that ZONEMD only be used when digest calculation time is 774 significantly less than propagation times and update intervals. 776 The authors' implementation (Appendix B.1) includes an option to 777 record and report CPU usage of its operation. The software was used 778 to generate digests for more than 800 TLD zones available from 779 [CZDS]. The table below summarizes the results for the SIMPLE scheme 780 and SHA384 hash algorithm grouped by zone size. The Rate column is 781 the mean amount of time per RR to calculate the digest, running on 782 commodity hardware in early 2020. 784 +---------------------+----------------+ 785 | Zone Size (RRs) | Rate (msec/RR) | 786 +---------------------+----------------+ 787 | 10 - 99 | 0.00683 | 788 | 100 - 999 | 0.00551 | 789 | 1000 - 9999 | 0.00505 | 790 | 10000 - 99999 | 0.00602 | 791 | 100000 - 999999 | 0.00845 | 792 | 1000000 - 9999999 | 0.0108 | 793 | 10000000 - 99999999 | 0.0148 | 794 +---------------------+----------------+ 796 For example, based on the above table, it takes approximately 0.13 797 seconds to calculate a SIMPLE SHA384 digest for a zone with 22,000 798 RRs, and about 2.5 seconds for a zone with 300,000 RRs. 800 These benchmarks attempt to emulate a worst-case scenario and take 801 into account the time required to canonicalize the zone for 802 processing. Each of the 800+ zones were measured three times, and 803 then averaged, with a different random sorting of the input data 804 prior to each measurement. 806 8. Privacy Considerations 808 This specification has no impact on user privacy. 810 9. Acknowledgments 812 The authors wish to thank David Blacka, Scott Hollenbeck, and Rick 813 Wilhelm for providing feedback on early drafts of this document. 814 Additionally, they thank Joe Abley, Mark Andrews, Ralph Dolmans, 815 Donald Eastlake, Richard Gibson, Olafur Gudmundsson, Bob Harold, Paul 816 Hoffman, Evan Hunt, Shumon Huque, Tatuya Jinmei, Mike St. Johns, Burt 817 Kaliski, Shane Kerr, Matt Larson, Barry Leiba, John Levine, Ed Lewis, 818 Matt Pounsett, Mukund Sivaraman, Petr Spacek, Ondrej Sury, Willem 819 Toorop, Florian Weimer, Tim Wicinksi, Wouter Wijngarrds, Paul 820 Wouters, and other members of the dnsop working group for their 821 input. 823 10. Change Log 825 RFC Editor: Please remove this section before publication. 827 This section lists substantial changes to the document as it is being 828 worked on. 830 From -00 to -01: 832 o Removed requirement to sort by RR CLASS. 834 o Added Kumari and Hardaker as coauthors. 836 o Added Change Log section. 838 o Minor clarifications and grammatical edits. 840 From -01 to -02: 842 o Emphasize desire for data security over channel security. 844 o Expanded motivation into its own subsection. 846 o Removed discussion topic whether or not to include serial in 847 ZONEMD. 849 o Clarified that a zone's NS records always sort before the SOA 850 record. 852 o Clarified that all records in the zone must are digested, except 853 as specified in the exclusion rules. 855 o Added for discussion out-of-zone and occluded records. 857 o Clarified that update of ZONEMD signature must not cause a serial 858 number change. 860 o Added persons to acknowledgments. 862 From -02 to -03: 864 o Added recommendation to set ZONEMD TTL to SOA TTL. 866 o Clarified that digest input uses uncompressed names. 868 o Updated Implementations section. 870 o Changed intended status from Standards Track to Experimental and 871 added Scope of Experiment section. 873 o Updated Motivation, Introduction, and Design Overview sections in 874 response to working group discussion. 876 o Gave ZONEMD digest types their own status, separate from DS digest 877 types. Request IANA to create a registry. 879 o Added Reserved field for future work supporting dynamic updates. 881 o Be more rigorous about having just ONE ZONEMD record in the zone. 883 o Expanded use cases. 885 From -03 to -04: 887 o Added an appendix with example zones and digests. 889 o Clarified that only apex ZONEMD RRs shall be processed. 891 From -04 to -05: 893 o Made SHA384 the only supported ZONEMD digest type. 895 o Disassociated ZONEMD digest types from DS digest types. 897 o Updates to Introduction based on list feedback. 899 o Changed "zone file" to "zone" everywhere. 901 o Restored text about why ZONEMD has a Serial field. 903 o Clarified ordering of RRSets having same owner to be numerically 904 ascending. 906 o Clarified that all duplicate RRs (not just SOA) must be suppressed 907 in digest calculation. 909 o Clarified that the Reserved field must be set to zero and checked 910 for zero in verification. 912 o Clarified that occluded data must be included. 914 o Clarified procedure for verification, using temporary location for 915 received digest. 917 o Explained why Reserved field is 8-bits. 919 o IANA Considerations section now more specific. 921 o Added complex zone to examples. 923 o 925 From -05 to -06: 927 o RR type code 63 was assigned to ZONEMD by IANA. 929 From -06 to -07: 931 o Fixed mistakes in ZONEMD examples. 933 o Added private use Digest Type values 240-254. 935 o Clarified that Digest field must not be empty. 937 From -07 to draft-ietf-dnsop-dns-zone-digest-00: 939 o Adopted by dnsop. 941 o Clarified further that non-apex ZONEMD RRs have no meaning. 943 o Changed "provably [un]signed" to "provably [in]secure". 945 o Allow multiple ZONEMD RRs to support algorithm agility/rollovers. 947 o Describe verification when there are multiple ZONEMD RRs. 949 From -00 to -01: 951 o Simplified requirements around verifying multiple digests. Any 952 one match is sufficient. 954 o Updated implementation notes. 956 o Both implementations produce expected results on examples given in 957 this document. 959 From -01 to -02: 961 o Changed the name of the Reserved field to Parameter. 963 o Changed the name of Digest Type 1 from SHA384 to SHA384-STABLE. 965 o The meaning of the Parameter field now depends on Digest Type. 967 o No longer require Parameter field to be zero in verification. 969 o Updated a rule from earlier versions that said multiple ZONEMD RRs 970 were not allowed. 972 From -02 to -03: 974 o Changed the name of Digest Type 1 from SHA384-STABLE to 975 SHA384-SIMPLE. 977 o Changed document status from Experimental to Standards Track. 979 o Removed Scope of Experimentation section. 981 From -03 to -04: 983 o Addressing WGLC feedback. 985 o Changed from "Digest Type + Paramter" to "Scheme + Hash 986 Algorithm". This should make it more obvious how ZONEMD can be 987 expanded in the future with new schemes and hash algorithms, while 988 sacrificing some of the flexibility that the Parameter was 989 intended to provide. 991 o Note: old RDATA fields: Serial, Digest Type, Parameter, Digest. 993 o Note: new RDATA fields: Serial, Scheme, Hash Algorithm, Digest. 995 o Add new IANA requirement for a Scheme registry. 997 o Rearranged some sections and separated scheme-specific aspects 998 from general aspects of digest calculation. 1000 o When discussing multiple ZONEMD RRs, allow for Scheme, as well as 1001 Hash Algorithm, transition. 1003 o Added Performance Considerations section with some benchmarks. 1005 o Further clarifications about non-apex ZONEMD RRs. 1007 o Clarified inclusion rule for duplicate RRs. 1009 o Removed or lowercased some inappropriately used RFC 2119 key 1010 words. 1012 o Clarified that all ZONEMD RRs, even for unsupported hash 1013 algorithms, must be zeroized during digest calculation. 1015 o Added Resilience and Fragility to security considerations. 1017 o Updated examples since changes in this version result in different 1018 hash values. 1020 From -04 to -05: 1022 o Clarifications about non-apex and multiple ZONEMD RRs. 1024 o Clarifications about benchmark results. 1026 o Don't compute ZONEMD on-the-fly. 1028 o Specification Required for updates to ZONEMD protocol registries. 1030 o Other rewording based on WGLC feedback. 1032 o Updated RFC numbers for some references. 1034 o Use documentation IP addresses instead of loopback. 1036 o Updated examples in the appendix. 1038 From -05 to -06: 1040 o Per WG suggestion, no longer include any apex ZONEMD record in 1041 digest calculation. 1043 o Updated examples in the appendix. 1045 o Clarified verification procedure by describing a loop over all 1046 ZONEMD RRs. 1048 From -06 to -07: 1050 o Added NIC Chile Labs implementation. 1052 From -07 to -08: 1054 o Update an author's affiliation. 1056 o Clarified why placeholder RRs are still important (for NSEC/ 1057 NSEC3). 1059 o Moved subsection ("Order of RRSets Having the Same Owner Name") 1060 with single sentence paragraph up into parent section. 1062 From -08 to -09: 1064 o Moved format, ordering, inclusion/exclusion into a sub section 1065 specific to the SIMPLE scheme. 1067 o Further clarified rules about multiple ZONEMD RRs (AD comments). 1069 o Reworded rules about processing of duplicate zone RRs (AD 1070 comments). 1072 o Removed sentence about optional zeroing of digest prior to 1073 calculation (AD comments). 1075 o Other minor changes (AD comments). 1077 From -09 to -10: 1079 o Add clarification and reference to on-disk modification / 1080 corruption of zone files. 1082 o Added concerns that timing of KSK rollovers could affect 1083 validation of ZONEMD record. 1085 o Addressed SECDIR review and accepted most proposed edits. 1087 o From SECDIR review, require minimum digest length of 12 octets. 1089 o From SECDIR review, add SHA512 has hash algorithm 2. 1091 o From SECDIR review, say that ZONEMD RRs MAY be ignored by local 1092 policy. 1094 o Moved Implementation Status to an appendix with the intention to 1095 retain it in RFC. 1097 o In registry tables, changed Status column to Implementation 1098 Requirement. 1100 11. References 1102 11.1. Normative References 1104 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 1105 STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987, 1106 . 1108 [RFC1035] Mockapetris, P., "Domain names - implementation and 1109 specification", STD 13, RFC 1035, DOI 10.17487/RFC1035, 1110 November 1987, . 1112 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1113 Requirement Levels", BCP 14, RFC 2119, 1114 DOI 10.17487/RFC2119, March 1997, 1115 . 1117 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 1118 Rose, "Resource Records for the DNS Security Extensions", 1119 RFC 4034, DOI 10.17487/RFC4034, March 2005, 1120 . 1122 [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms 1123 (SHA and SHA-based HMAC and HKDF)", RFC 6234, 1124 DOI 10.17487/RFC6234, May 2011, 1125 . 1127 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1128 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1129 May 2017, . 1131 11.2. Informative References 1133 [CZDS] Internet Corporation for Assigned Names and Numbers, 1134 "Centralized Zone Data Service", October 2018, 1135 . 1137 [disk-full-failure] 1138 DENIC, "Background of the Partial Failure of the Name 1139 Service for .de Domains", May 2010, 1140 . 1143 [DnsTools] 1144 NIC Chile Labs, "DNS tools for zone signature (file, 1145 pkcs11-hsm) and validation, and zone digest (ZONEMD)", 1146 April 2020, . 1148 [InterNIC] 1149 ICANN, "InterNIC FTP site", May 2018, 1150 . 1152 [ldns-zone-digest] 1153 Verisign, "Implementation of Message Digests for DNS Zones 1154 using the ldns library", July 2018, 1155 . 1157 [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, 1158 DOI 10.17487/RFC1995, August 1996, 1159 . 1161 [RFC2065] Eastlake 3rd, D. and C. Kaufman, "Domain Name System 1162 Security Extensions", RFC 2065, DOI 10.17487/RFC2065, 1163 January 1997, . 1165 [RFC2136] Vixie, P., Ed., Thomson, S., Rekhter, Y., and J. Bound, 1166 "Dynamic Updates in the Domain Name System (DNS UPDATE)", 1167 RFC 2136, DOI 10.17487/RFC2136, April 1997, 1168 . 1170 [RFC2535] Eastlake 3rd, D., "Domain Name System Security 1171 Extensions", RFC 2535, DOI 10.17487/RFC2535, March 1999, 1172 . 1174 [RFC2845] Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B. 1175 Wellington, "Secret Key Transaction Authentication for DNS 1176 (TSIG)", RFC 2845, DOI 10.17487/RFC2845, May 2000, 1177 . 1179 [RFC2931] Eastlake 3rd, D., "DNS Request and Transaction Signatures 1180 ( SIG(0)s )", RFC 2931, DOI 10.17487/RFC2931, September 1181 2000, . 1183 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 1184 Thayer, "OpenPGP Message Format", RFC 4880, 1185 DOI 10.17487/RFC4880, November 2007, 1186 . 1188 [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet 1189 Mail Extensions (S/MIME) Version 3.2 Message 1190 Specification", RFC 5751, DOI 10.17487/RFC5751, January 1191 2010, . 1193 [RFC5936] Lewis, E. and A. Hoenes, Ed., "DNS Zone Transfer Protocol 1194 (AXFR)", RFC 5936, DOI 10.17487/RFC5936, June 2010, 1195 . 1197 [RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm 1198 Agility and Selecting Mandatory-to-Implement Algorithms", 1199 BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015, 1200 . 1202 [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., 1203 and P. Hoffman, "Specification for DNS over Transport 1204 Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 1205 2016, . 1207 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1208 Writing an IANA Considerations Section in RFCs", BCP 26, 1209 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1210 . 1212 [RFC8484] Hoffman, P. and P. McManus, "DNS Queries over HTTPS 1213 (DoH)", RFC 8484, DOI 10.17487/RFC8484, October 2018, 1214 . 1216 [RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS 1217 Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499, 1218 January 2019, . 1220 [RFC8806] Kumari, W. and P. Hoffman, "Running a Root Server Local to 1221 a Resolver", RFC 8806, DOI 10.17487/RFC8806, June 2020, 1222 . 1224 [RootServers] 1225 Root Server Operators, "Root Server Technical Operations", 1226 July 2018, . 1228 [RPZ] Vixie, P. and V. Schryver, "DNS Response Policy Zones 1229 (RPZ)", draft-vixie-dnsop-dns-rpz-00 (work in progress), 1230 June 2018, . 1233 [ZoneDigestHackathon] 1234 Kerr, S., "Prototype implementation of ZONEMD for the IETF 1235 102 hackathon in Python", July 2018, 1236 . 1238 Appendix A. Example Zones With Digests 1240 This appendix contains example zones with accurate ZONEMD records. 1241 These can be used to verify an implementation of the zone digest 1242 protocol. 1244 A.1. Simple EXAMPLE Zone 1246 Here, the EXAMPLE zone contains an SOA record, NS and glue records, 1247 and a ZONEMD record. 1249 example. 86400 IN SOA ns1 admin 2018031900 ( 1250 1800 900 604800 86400 ) 1251 86400 IN NS ns1 1252 86400 IN NS ns2 1253 86400 IN ZONEMD 2018031900 1 1 ( 1254 c68090d90a7aed71 1255 6bc459f9340e3d7c 1256 1370d4d24b7e2fc3 1257 a1ddc0b9a87153b9 1258 a9713b3c9ae5cc27 1259 777f98b8e730044c ) 1260 ns1 3600 IN A 203.0.113.63 1261 ns2 3600 IN AAAA 2001:db8::63 1263 A.2. Complex EXAMPLE Zone 1265 Here, the EXAMPLE zone contains duplicate RRs, and an occluded RR, 1266 and one out-of-zone RR. 1268 example. 86400 IN SOA ns1 admin 2018031900 ( 1269 1800 900 604800 86400 ) 1270 86400 IN NS ns1 1271 86400 IN NS ns2 1272 86400 IN ZONEMD 2018031900 1 1 ( 1273 31cefb03814f5062 1274 ad12fa951ba0ef5f 1275 8da6ae354a415767 1276 246f7dc932ceb1e7 1277 42a2108f529db6a3 1278 3a11c01493de358d ) 1279 ns1 3600 IN A 203.0.113.63 1280 ns2 3600 IN AAAA 2001:db8::63 1281 occluded.sub 7200 IN TXT "I'm occluded but must be digested" 1282 sub 7200 IN NS ns1 1283 duplicate 300 IN TXT "I must be digested just once" 1284 duplicate 300 IN TXT "I must be digested just once" 1285 foo.test. 555 IN TXT "out-of-zone data must be excluded" 1286 non-apex 900 IN ZONEMD 2018031900 1 1 ( 1287 616c6c6f77656420 1288 6275742069676e6f 1289 7265642e20616c6c 1290 6f77656420627574 1291 2069676e6f726564 1292 2e20616c6c6f7765 ) 1294 A.3. EXAMPLE Zone with multiple digests 1296 Here, the EXAMPLE zone contains multiple ZONEMD records. It has both 1297 SHA384 and SHA512 digests using the SIMPLE scheme. It also includes 1298 ZONEMD records with Scheme and Hash Algorithm values in the private 1299 range (240-254). These additional private-range digests are not 1300 verifiable. 1302 example. 86400 IN SOA ns1 admin 2018031900 ( 1303 1800 900 604800 86400 ) 1304 example. 86400 IN NS ns1.example. 1305 example. 86400 IN NS ns2.example. 1306 example. 86400 IN ZONEMD 2018031900 1 1 ( 1307 62e6cf51b02e54b9 1308 b5f967d547ce4313 1309 6792901f9f88e637 1310 493daaf401c92c27 1311 9dd10f0edb1c56f8 1312 080211f8480ee306 ) 1313 example. 86400 IN ZONEMD 2018031900 1 2 ( 1314 08cfa1115c7b948c 1315 4163a901270395ea 1316 226a930cd2cbcf2f 1317 a9a5e6eb85f37c8a 1318 4e114d884e66f176 1319 eab121cb02db7d65 1320 2e0cc4827e7a3204 1321 f166b47e5613fd27 ) 1322 example. 86400 IN ZONEMD 2018031900 1 240 ( 1323 e2d523f654b9422a 1324 96c5a8f44607bbee ) 1325 example. 86400 IN ZONEMD 2018031900 241 1 ( 1326 e1846540e33a9e41 1327 89792d18d5d131f6 1328 05fc283e ) 1329 ns1.example. 3600 IN A 203.0.113.63 1330 ns2.example. 86400 IN TXT "This example has multiple digests" 1331 ns2.example. 3600 IN AAAA 2001:db8::63 1333 A.4. The URI.ARPA Zone 1335 The URI.ARPA zone retrieved 2018-10-21. Note this sample zone has 1336 (expired) signatures, but no signature for the ZONEMD RR. 1338 ; <<>> DiG 9.9.4 <<>> @lax.xfr.dns.icann.org uri.arpa axfr 1339 ; (2 servers found) 1340 ;; global options: +cmd 1341 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1342 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1343 uri.arpa. 3600 IN RRSIG NSEC 8 2 3600 ( 1344 20181028142623 20181007205525 47155 uri.arpa. 1345 eEC4w/oXLR1Epwgv4MBiDtSBsXhqrJVvJWUpbX8XpetAvD35bxwNCUTi 1346 /pAJVUXefegWeiriD2rkTgCBCMmn7YQIm3gdR+HjY/+o3BXNQnz97f+e 1347 HAE9EDDzoNVfL1PyV/2fde9tDeUuAGVVwmD399NGq9jWYMRpyri2kysr q/g= ) 1348 uri.arpa. 86400 IN RRSIG NS 8 2 86400 ( 1349 20181028172020 20181007175821 47155 uri.arpa. 1351 ATyV2A2A8ZoggC+68u4GuP5MOUuR+2rr3eWOkEU55zAHld/7FiBxl4ln 1352 4byJYy7NudUwlMOEXajqFZE7DVl8PpcvrP3HeeGaVzKqaWj+aus0jbKF 1353 Bsvs2b1qDZemBfkz/IfAhUTJKnto0vSUicJKfItu0GjyYNJCz2CqEuGD Wxc= ) 1354 uri.arpa. 600 IN RRSIG MX 8 2 600 ( 1355 20181028170556 20181007175821 47155 uri.arpa. 1356 e7/r3KXDohX1lyVavetFFObp8fB8aXT76HnN9KCQDxSnSghNM83UQV0t 1357 lTtD8JVeN1mCvcNFZpagwIgB7XhTtm6Beur/m5ES+4uSnVeS6Q66HBZK 1358 A3mR95IpevuVIZvvJ+GcCAQpBo6KRODYvJ/c/ZG6sfYWkZ7qg/Em5/+3 4UI= ) 1359 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1360 20181028152832 20181007175821 15796 uri.arpa. 1361 nzpbnh0OqsgBBP8St28pLvPEQ3wZAUdEBuUwil+rtjjWlYYiqjPxZ286 1362 XF4Rq1usfV5x71jZz5IqswOaQgia91ylodFpLuXD6FTGs2nXGhNKkg1V 1363 chHgtwj70mXU72GefVgo8TxrFYzxuEFP5ZTP92t97FVWVVyyFd86sbbR 1364 6DZj3uA2wEvqBVLECgJLrMQ9Yy7MueJl3UA4h4E6zO2JY9Yp0W9woq0B 1365 dqkkwYTwzogyYffPmGAJG91RJ2h6cHtFjEZe2MnaY2glqniZ0WT9vXXd 1366 uFPm0KD9U77Ac+ZtctAF9tsZwSdAoL365E2L1usZbA+K0BnPPqGFJRJk 1367 5R0A1w== ) 1368 uri.arpa. 3600 IN RRSIG DNSKEY 8 2 3600 ( 1369 20181028152832 20181007175821 55480 uri.arpa. 1370 lWtQV/5szQjkXmbcD47/+rOW8kJPksRFHlzxxmzt906+DBYyfrH6uq5X 1371 nHvrUlQO6M12uhqDeL+bDFVgqSpNy+42/OaZvaK3J8EzPZVBHPJykKMV 1372 63T83aAiJrAyHzOaEdmzLCpalqcEE2ImzlLHSafManRfJL8Yuv+JDZFj 1373 2WDWfEcUuwkmIZWX11zxp+DxwzyUlRl7x4+ok5iKZWIg5UnBAf6B8T75 1374 WnXzlhCw3F2pXI0a5LYg71L3Tp/xhjN6Yy9jGlIRf5BjB59X2zra3a2R 1375 PkI09SSnuEwHyF1mDaV5BmQrLGRnCjvwXA7ho2m+vv4SP5dUdXf+GTeA 1376 1HeBfw== ) 1377 uri.arpa. 3600 IN RRSIG SOA 8 2 3600 ( 1378 20181029114753 20181008222815 47155 uri.arpa. 1379 qn8yBNoHDjGdT79U2Wu9IIahoS0YPOgYP8lG+qwPcrZ1BwGiHywuoUa2 1380 Mx6BWZlg+HDyaxj2iOmox+IIqoUHhXUbO7IUkJFlgrOKCgAR2twDHrXu 1381 9BUQHy9SoV16wYm3kBTEPyxW5FFm8vcdnKAF7sxSY8BbaYNpRIEjDx4A JUc= ) 1382 uri.arpa. 3600 IN NSEC ftp.uri.arpa. NS SOA ( 1383 MX RRSIG NSEC DNSKEY ) 1384 uri.arpa. 86400 IN NS a.iana-servers.net. 1385 uri.arpa. 86400 IN NS b.iana-servers.net. 1386 uri.arpa. 86400 IN NS c.iana-servers.net. 1387 uri.arpa. 86400 IN NS ns2.lacnic.net. 1388 uri.arpa. 86400 IN NS sec3.apnic.net. 1389 uri.arpa. 600 IN MX 10 pechora.icann.org. 1390 uri.arpa. 3600 IN DNSKEY 256 3 8 ( 1391 AwEAAcBi7tSart2J599zbYWspMNGN70IBWb4ziqyQYH9MTB/VCz6WyUK 1392 uXunwiJJbbQ3bcLqTLWEw134B6cTMHrZpjTAb5WAwg4XcWUu8mdcPTiL 1393 Bl6qVRlRD0WiFCTzuYUfkwsh1Rbr7rvrxSQhF5rh71zSpwV5jjjp65Wx 1394 SdJjlH0B ) 1395 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1396 AwEAAbNVv6ulgRdO31MtAehz7j3ALRjwZglWesnzvllQl/+hBRZr9QoY 1397 cO2I+DkO4Q1NKxox4DUIxj8SxPO3GwDuOFR9q2/CFi2O0mZjafbdYtWc 1398 3zSdBbi3q0cwCIx7GuG9eqlL+pg7mdk9dgdNZfHwB0LnqTD8ebLPsrO/ 1399 Id7kBaiqYOfMlZnh2fp+2h6OOJZHtY0DK1UlssyB5PKsE0tVzo5s6zo9 1400 iXKe5u+8WTMaGDY49vG80JPAKE7ezMiH/NZcUMiE0PRZ8D3foq2dYuS5 1401 ym+vA83Z7v8A+Rwh4UGnjxKB8zmr803V0ASAmHz/gwH5Vb0nH+LObwFt 1402 l3wpbp+Wpm8= ) 1403 uri.arpa. 3600 IN DNSKEY 257 3 8 ( 1404 AwEAAbwnFTakCvaUKsXji4mgmxZUJi1IygbnGahbkmFEa0L16J+TchKR 1405 wcgzVfsxUGa2MmeA4hgkAooC3uy+tTmoMsgy8uq/JAj24DjiHzd46LfD 1406 FK/qMidVqFpYSHeq2Vv5ojkuIsx4oe4KsafGWYNOczKZgH5loGjN2aJG 1407 mrIm++XCphOskgCsQYl65MIzuXffzJyxlAuts+ecAIiVeqRaqQfr8LRU 1408 7wIsLxinXirprtQrbor+EtvlHp9qXE6ARTZDzf4jvsNpKvLFZtmxzFf3 1409 e/UJz5eHjpwDSiZL7xE8aE1o1nGfPtJx9ZnB3bapltaJ5wY+5XOCKgY0 1410 xmJVvNQlwdE= ) 1411 ftp.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1412 20181028080856 20181007175821 47155 uri.arpa. 1413 HClGAqPxzkYkAT7Q/QNtQeB6YrkP6EPOef+9Qo5/2zngwAewXEAQiyF9 1414 jD1USJiroM11QqBS3v3aIdW/LXORs4Ez3hLcKNO1cKHsOuWAqzmE+BPP 1415 Arfh8N95jqh/q6vpaB9UtMkQ53tM2fYU1GszOLN0knxbHgDHAh2axMGH lqM= ) 1416 ftp.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1417 20181028103644 20181007205525 47155 uri.arpa. 1418 WoLi+vZzkxaoLr2IGZnwkRvcDf6KxiWQd1WZP/U+AWnV+7MiqsWPZaf0 1419 9toRErerGoFOiOASNxZjBGJrRgjmavOM9U+LZSconP9zrNFd4dIu6kp5 1420 YxlQJ0uHOvx1ZHFCj6lAt1ACUIw04ZhMydTmi27c8MzEOMepvn7iH7r7 k7k= ) 1421 ftp.uri.arpa. 3600 IN NSEC http.uri.arpa. NAPTR ( 1422 RRSIG NSEC ) 1423 ftp.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1424 "!^ftp://([^:/?#]*).*$!\\1!i" . ) 1425 http.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1426 20181029010647 20181007175821 47155 uri.arpa. 1427 U03NntQ73LHWpfLmUK8nMsqkwVsOGW2KdsyuHYAjqQSZvKbtmbv7HBmE 1428 H1+Ii3Z+wtfdMZBy5aC/6sHdx69BfZJs16xumycMlAy6325DKTQbIMN+ 1429 ift9GrKBC7cgCd2msF/uzSrYxxg4MJQzBPvlkwXnY3b7eJSlIXisBIn7 3b8= ) 1430 http.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1431 20181029011815 20181007205525 47155 uri.arpa. 1432 T7mRrdag+WSmG+n22mtBSQ/0Y3v+rdDnfQV90LN5Fq32N5K2iYFajF7F 1433 Tp56oOznytfcL4fHrqOE0wRc9NWOCCUec9C7Wa1gJQcllEvgoAM+L6f0 1434 RsEjWq6+9jvlLKMXQv0xQuMX17338uoD/xiAFQSnDbiQKxwWMqVAimv5 7Zs= ) 1435 http.uri.arpa. 3600 IN NSEC mailto.uri.arpa. NAPTR ( 1436 RRSIG NSEC ) 1437 http.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1438 "!^http://([^:/?#]*).*$!\\1!i" . ) 1439 mailto.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1440 20181028110727 20181007175821 47155 uri.arpa. 1441 GvxzVL85rEukwGqtuLxek9ipwjBMfTOFIEyJ7afC8HxVMs6mfFa/nEM/ 1442 IdFvvFg+lcYoJSQYuSAVYFl3xPbgrxVSLK125QutCFMdC/YjuZEnq5cl 1443 fQciMRD7R3+znZfm8d8u/snLV9w4D+lTBZrJJUBe1Efc8vum5vvV7819 ZoY= ) 1444 mailto.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1445 20181028141825 20181007205525 47155 uri.arpa. 1446 MaADUgc3fc5v++M0YmqjGk3jBdfIA5RuP62hUSlPsFZO4k37erjIGCfF 1447 j+g84yc+QgbSde0PQHszl9fE/+SU5ZXiS9YdcbzSZxp2erFpZOTchrpg 1448 916T4vx6i59scodjb0l6bDyZ+mtIPrc1w6b4hUyOUTsDQoAJYxdfEuMg Vy4= ) 1449 mailto.uri.arpa. 3600 IN NSEC urn.uri.arpa. NAPTR ( 1450 RRSIG NSEC ) 1451 mailto.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1452 "!^mailto:(.*)@(.*)$!\\2!i" . ) 1453 urn.uri.arpa. 3600 IN RRSIG NSEC 8 3 3600 ( 1454 20181028123243 20181007175821 47155 uri.arpa. 1455 Hgsw4Deops1O8uWyELGe6hpR/OEqCnTHvahlwiQkHhO5CSEQrbhmFAWe 1456 UOkmGAdTEYrSz+skLRQuITRMwzyFf4oUkZihGyhZyzHbcxWfuDc/Pd/9 1457 DSl56gdeBwy1evn5wBTms8yWQVkNtphbJH395gRqZuaJs3LD/qTyJ5Dp LvA= ) 1458 urn.uri.arpa. 604800 IN RRSIG NAPTR 8 3 604800 ( 1459 20181029071816 20181007205525 47155 uri.arpa. 1460 ALIZD0vBqAQQt40GQ0Efaj8OCyE9xSRJRdyvyn/H/wZVXFRFKrQYrLAS 1461 D/K7q6CMTOxTRCu2J8yes63WJiaJEdnh+dscXzZkmOg4n5PsgZbkvUSW 1462 BiGtxvz5jNncM0xVbkjbtByrvJQAO1cU1mnlDKe1FmVB1uLpVdA9Ib4J hMU= ) 1463 urn.uri.arpa. 3600 IN NSEC uri.arpa. NAPTR RRSIG ( 1464 NSEC ) 1465 urn.uri.arpa. 604800 IN NAPTR 0 0 "" "" ( 1466 "/urn:([^:]+)/\\1/i" . ) 1467 uri.arpa. 3600 IN SOA sns.dns.icann.org. ( 1468 noc.dns.icann.org. 2018100702 10800 3600 1209600 3600 ) 1469 ;; Query time: 66 msec 1470 ;; SERVER: 192.0.32.132#53(192.0.32.132) 1471 ;; WHEN: Sun Oct 21 20:39:28 UTC 2018 1472 ;; XFR size: 34 records (messages 1, bytes 3941) 1473 uri.arpa. 3600 IN ZONEMD 2018100702 1 1 ( 1474 1291b78ddf7669b1a39d014d87626b709b55774c5d7d58fa 1475 dc556439889a10eaf6f11d615900a4f996bd46279514e473 ) 1477 A.5. The ROOT-SERVERS.NET Zone 1479 The ROOT-SERVERS.NET zone retrieved 2018-10-21. 1481 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1482 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1483 root-servers.net. 3600000 IN NS a.root-servers.net. 1484 root-servers.net. 3600000 IN NS b.root-servers.net. 1485 root-servers.net. 3600000 IN NS c.root-servers.net. 1486 root-servers.net. 3600000 IN NS d.root-servers.net. 1487 root-servers.net. 3600000 IN NS e.root-servers.net. 1488 root-servers.net. 3600000 IN NS f.root-servers.net. 1489 root-servers.net. 3600000 IN NS g.root-servers.net. 1490 root-servers.net. 3600000 IN NS h.root-servers.net. 1491 root-servers.net. 3600000 IN NS i.root-servers.net. 1492 root-servers.net. 3600000 IN NS j.root-servers.net. 1493 root-servers.net. 3600000 IN NS k.root-servers.net. 1494 root-servers.net. 3600000 IN NS l.root-servers.net. 1495 root-servers.net. 3600000 IN NS m.root-servers.net. 1496 a.root-servers.net. 3600000 IN AAAA 2001:503:ba3e::2:30 1497 a.root-servers.net. 3600000 IN A 198.41.0.4 1498 b.root-servers.net. 3600000 IN MX 20 mail.isi.edu. 1499 b.root-servers.net. 3600000 IN AAAA 2001:500:200::b 1500 b.root-servers.net. 3600000 IN A 199.9.14.201 1501 c.root-servers.net. 3600000 IN AAAA 2001:500:2::c 1502 c.root-servers.net. 3600000 IN A 192.33.4.12 1503 d.root-servers.net. 3600000 IN AAAA 2001:500:2d::d 1504 d.root-servers.net. 3600000 IN A 199.7.91.13 1505 e.root-servers.net. 3600000 IN AAAA 2001:500:a8::e 1506 e.root-servers.net. 3600000 IN A 192.203.230.10 1507 f.root-servers.net. 3600000 IN AAAA 2001:500:2f::f 1508 f.root-servers.net. 3600000 IN A 192.5.5.241 1509 g.root-servers.net. 3600000 IN AAAA 2001:500:12::d0d 1510 g.root-servers.net. 3600000 IN A 192.112.36.4 1511 h.root-servers.net. 3600000 IN AAAA 2001:500:1::53 1512 h.root-servers.net. 3600000 IN A 198.97.190.53 1513 i.root-servers.net. 3600000 IN MX 10 mx.i.root-servers.org. 1514 i.root-servers.net. 3600000 IN AAAA 2001:7fe::53 1515 i.root-servers.net. 3600000 IN A 192.36.148.17 1516 j.root-servers.net. 3600000 IN AAAA 2001:503:c27::2:30 1517 j.root-servers.net. 3600000 IN A 192.58.128.30 1518 k.root-servers.net. 3600000 IN AAAA 2001:7fd::1 1519 k.root-servers.net. 3600000 IN A 193.0.14.129 1520 l.root-servers.net. 3600000 IN AAAA 2001:500:9f::42 1521 l.root-servers.net. 3600000 IN A 199.7.83.42 1522 m.root-servers.net. 3600000 IN AAAA 2001:dc3::35 1523 m.root-servers.net. 3600000 IN A 202.12.27.33 1524 root-servers.net. 3600000 IN SOA a.root-servers.net. ( 1525 nstld.verisign-grs.com. 2018091100 14400 7200 1209600 3600000 ) 1526 root-servers.net. 3600000 IN ZONEMD 2018091100 1 1 ( 1527 f1ca0ccd91bd5573d9f431c00ee0101b2545c97602be0a97 1528 8a3b11dbfc1c776d5b3e86ae3d973d6b5349ba7f04340f79 ) 1530 Appendix B. Implementation Status 1532 RFC Editor: Please retain this section upon publication. 1534 This section records the status of known implementations of the 1535 protocol defined by this specification at the time of posting of this 1536 Internet-Draft, and is based on a proposal described in RFC 7942. 1537 The description of implementations in this section is intended to 1538 assist the IETF in its decision processes in progressing drafts to 1539 RFCs. Please note that the listing of any individual implementation 1540 here does not imply endorsement by the IETF. Furthermore, no effort 1541 has been spent to verify the information presented here that was 1542 supplied by IETF contributors. This is not intended as, and must not 1543 be construed to be, a catalog of available implementations or their 1544 features. Readers are advised to note that other implementations may 1545 exist. 1547 B.1. Authors' Implementation 1549 The authors have an open source implementation in C, using the ldns 1550 library [ldns-zone-digest]. This implementation is able to perform 1551 the following functions: 1553 o Read an input zone and output a zone with the ZONEMD placeholder. 1555 o Compute zone digest over signed zone and update the ZONEMD record. 1557 o Re-compute DNSSEC signature over the ZONEMD record. 1559 o Verify the zone digest from an input zone. 1561 This implementation does not: 1563 o Perform DNSSEC validation of the ZONEMD record during 1564 verification. 1566 B.2. Shane Kerr's Implementation 1568 Shane Kerr wrote an implementation of this specification during the 1569 IETF 102 hackathon [ZoneDigestHackathon]. This implementation is in 1570 Python and is able to perform the following functions: 1572 o Read an input zone and output a zone with ZONEMD record. 1574 o Verify the zone digest from an input zone. 1576 o Output the ZONEMD record in its defined presentation format. 1578 This implementation does not: 1580 o Re-compute DNSSEC signature over the ZONEMD record. 1582 o Perform DNSSEC validation of the ZONEMD record. 1584 B.3. NIC Chile Labs Implementation 1586 NIC Chile Labs wrote an implementation of this specification as part 1587 of "dns-tools" suite [DnsTools], which besides digesting, can also 1588 sign and verify zones. This implementation is in Go and is able to 1589 perform the following functions: 1591 o Compute zone digest over signed zone and update the ZONEMD record. 1593 o Verify the zone digest from an input zone. 1595 o Perform DNSSEC validation of the ZONEMD record during 1596 verification. 1598 o Re-compute DNSSEC signature over the ZONEMD record. 1600 Authors' Addresses 1602 Duane Wessels 1603 Verisign 1604 12061 Bluemont Way 1605 Reston, VA 20190 1607 Phone: +1 703 948-3200 1608 Email: dwessels@verisign.com 1609 URI: https://verisign.com 1611 Piet Barber 1612 Verisign 1613 12061 Bluemont Way 1614 Reston, VA 20190 1616 Phone: +1 703 948-3200 1617 Email: pbarber@verisign.com 1618 URI: https://verisign.com 1619 Matt Weinberg 1620 Amazon 1622 Email: matweinb@amazon.com 1623 URI: https://amazon.com 1625 Warren Kumari 1626 Google 1627 1600 Amphitheatre Parkway 1628 Mountain View, CA 94043 1630 Email: warren@kumari.net 1632 Wes Hardaker 1633 USC/ISI 1634 P.O. Box 382 1635 Davis, CA 95617 1637 Email: ietf@hardakers.net