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Checking references for intended status: Experimental ---------------------------------------------------------------------------- == Unused Reference: 'RFC2181' is defined on line 481, but no explicit reference was found in the text == Unused Reference: 'RFC5233' is defined on line 493, but no explicit reference was found in the text == Unused Reference: 'RFC7129' is defined on line 513, but no explicit reference was found in the text -- No information found for draft-dane-openpgpkey-usage - is the name correct? -- Obsolete informational reference (is this intentional?): RFC 2822 (Obsoleted by RFC 5322) Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group P. Wouters 3 Internet-Draft Red Hat 4 Intended status: Experimental August 27, 2015 5 Expires: February 28, 2016 7 Using DANE to Associate OpenPGP public keys with email addresses 8 draft-ietf-dane-openpgpkey-04 10 Abstract 12 OpenPGP is a message format for email (and file) encryption that 13 lacks a standardized lookup mechanism to securely obtain OpenPGP 14 public keys. This document specifies a method for publishing and 15 locating OpenPGP public keys in DNS for a specific email address 16 using a new OPENPGPKEY DNS Resource Record. Security is provided via 17 DNSSEC. 19 Status of This Memo 21 This Internet-Draft is submitted in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF). Note that other groups may also distribute 26 working documents as Internet-Drafts. The list of current Internet- 27 Drafts is at http://datatracker.ietf.org/drafts/current/. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 This Internet-Draft will expire on February 28, 2016. 36 Copyright Notice 38 Copyright (c) 2015 IETF Trust and the persons identified as the 39 document authors. All rights reserved. 41 This document is subject to BCP 78 and the IETF Trust's Legal 42 Provisions Relating to IETF Documents 43 (http://trustee.ietf.org/license-info) in effect on the date of 44 publication of this document. Please review these documents 45 carefully, as they describe your rights and restrictions with respect 46 to this document. Code Components extracted from this document must 47 include Simplified BSD License text as described in Section 4.e of 48 the Trust Legal Provisions and are provided without warranty as 49 described in the Simplified BSD License. 51 Table of Contents 53 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 54 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 55 2. The OPENPGPKEY Resource Record . . . . . . . . . . . . . . . 3 56 2.1. The OPENPGPKEY RDATA component . . . . . . . . . . . . . 4 57 2.1.1. The OPENPGPKEY RDATA content . . . . . . . . . . . . 4 58 2.1.2. Reducing the Transferable Public Key size . . . . . . 5 59 2.2. The OPENPGPKEY RDATA wire format . . . . . . . . . . . . 5 60 2.3. The OPENPGPKEY RDATA presentation format . . . . . . . . 5 61 3. Location of the OPENPGPKEY record . . . . . . . . . . . . . . 5 62 4. Email address variants . . . . . . . . . . . . . . . . . . . 6 63 5. Application use of OPENPGPKEY . . . . . . . . . . . . . . . . 7 64 5.1. Obtaining an OpenPGP key for a specific email address . . 7 65 5.2. Confirming the validity of an OpenPGP key . . . . . . . . 7 66 5.3. Verifying an unknown OpenPGP signature . . . . . . . . . 7 67 6. OpenPGP Key size and DNS . . . . . . . . . . . . . . . . . . 7 68 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 69 7.1. Response size . . . . . . . . . . . . . . . . . . . . . . 8 70 7.2. Email address information leak . . . . . . . . . . . . . 8 71 7.3. Storage of OPENPGPKEY data . . . . . . . . . . . . . . . 9 72 7.4. Forward security of OpenPGP versus DNSSEC . . . . . . . . 9 73 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 74 8.1. OPENPGPKEY RRtype . . . . . . . . . . . . . . . . . . . . 10 75 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 76 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 77 10.1. Normative References . . . . . . . . . . . . . . . . . . 10 78 10.2. Informative References . . . . . . . . . . . . . . . . . 11 79 Appendix A. Generating OPENPGPKEY records . . . . . . . . . . . 12 80 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13 82 1. Introduction 84 OpenPGP [RFC4880] public keys are used to encrypt or sign email 85 messages and files. To encrypt an email message, or verify a 86 sender's OpenPGP signature, the email client or MTA needs to locate 87 the recipient's OpenPGP public key. 89 OpenPGP clients have relied on centralized "well-known" key servers 90 that are accessed using either the HTTP Keyserver Protocol [HKP] 91 Alternatively, users need to manually browse a variety of different 92 front-end websites. These key servers do not validate the email 93 address in the User ID of the uploaded OpenPGP public key. Attackers 94 can - and have - uploaded rogue public keys with other people's email 95 addresses to these key servers. 97 Once uploaded, public keys cannot be deleted. People who did not 98 pre-sign a key revocation can never remove their OpenPGP public key 99 from these key servers once they have lost access to their private 100 key. This results in receiving encrypted email that cannot be 101 decrypted. 103 Therefor, these keyservers are not well suited to support email 104 clients and MTA's to automatically encrypt email - especially in the 105 absence of an interactive user. 107 This document describes a mechanism to associate a user's OpenPGP 108 public key with their email address, using the OPENPGPKEY DNS RRtype. 109 These records are published in the DNS zone of the user's email 110 address. If the user loses their private key, the OPENPGPKEY DNS 111 record can simply be updated or removed from the zone. 113 The proposed new DNS Resource Record type is secured using DNSSEC. 114 This trust model is not meant to replace the Web Of Trust model. 116 1.1. Terminology 118 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 119 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 120 document are to be interpreted as described in RFC 2119 [RFC2119]. 122 This document also makes use of standard DNSSEC and DANE terminology. 123 See DNSSEC [RFC4033], [RFC4034], [RFC4035], and DANE [RFC6698] for 124 these terms. 126 2. The OPENPGPKEY Resource Record 128 The OPENPGPKEY DNS resource record (RR) is used to associate an end 129 entity OpenPGP Transferable Public Key (see Section 11.1 of [RFC4880] 130 with an email address, thus forming a "OpenPGP public key 131 association". A user that wishes to specify more than one OpenPGP 132 key, for example because they are transitioning to a newer stronger 133 key, can do so by adding multiple OPENPGPKEY records. A single 134 OPENPGPKEY DNS record MUST only contain one OpenPGP key. 136 The type value allocated for the OPENPGPKEY RR type is 61. The 137 OPENPGPKEY RR is class independent. The OPENPGPKEY RR has no special 138 TTL requirements. 140 2.1. The OPENPGPKEY RDATA component 142 The RDATA portion of an OPENPGPKEY Resource Record contains a single 143 value consisting of a [RFC4880] formatted Transferable Public Key. 145 2.1.1. The OPENPGPKEY RDATA content 147 An OpenPGP Transferable Public Key can be arbitrarily large. DNS 148 records are limited in size. When creating OPENPGPKEY DNS records, 149 the OpenPGP Transferable Public Key should be filtered to only 150 contain appropriate and useful data. At a minimum, an OPENPGPKEY 151 Transferable Public Key for the user hugh@example.com should contain: 153 o The primary key X 154 o One User ID Y, which SHOULD match 'hugh@example.com' 155 o self-signature from X, binding X to Y 157 If the primary key is not encryption-capable, a relevant subkey 158 should be included resulting in an OPENPGPKEY Transferable Public Key 159 containing: 161 o The primary key X 162 o One User ID Y, which SHOULD match 'hugh@example.com' 163 o self-signature from X, binding X to Y 164 o encryption-capable subkey Z 165 o self-signature from X, binding Z to X 166 o [ other subkeys if relevant ... ] 168 The user can also elect to add a few third-party certifications which 169 they believe would be helpful for validation in the traditional Web 170 Of Trust. The resulting OPENPGPKEY Transferable Public Key would 171 then look like: 173 o The primary key X 174 o One User ID Y, which SHOULD match 'hugh@example.com' 175 o self-signature from X, binding X to Y 176 o third-party certification from V, binding Y to X 177 o [ other third-party certifications if relevant ... ] 178 o encryption-capable subkey Z 179 o self-signature from X, binding Z to X 180 o [ other subkeys if relevant ... ] 182 2.1.2. Reducing the Transferable Public Key size 184 When preparing a Transferable Public Key for a specific OPENPGPKEY 185 RDATA format with the goal of minimizing certificate size, a user 186 would typically want to: 188 o Where one User ID from the certifications matches the looked-up 189 address, strip away non-matching User IDs and any associated 190 certifications (self-signatures or third-party certifications) 192 o Strip away all User Attribute packets and associated 193 certifications Strip away all expired subkeys. The user may want 194 to keep revoked subkeys if these were revoked prior to their 195 preferred expiration time to ensure that correspondents know about 196 these earlier then expected revocations. 198 o strip away all but the most recent self-sig for the remaining user 199 IDs and subkeys 201 o Optionally strip away any uninteresting or unimportant third-party 202 User ID certifications. This is a value judgment by the user that 203 is difficult to automate. At the very least, expired and 204 superseded third-party certifcations should be stripped out. The 205 user should attempt to keep the most recent and most well 206 connected certifications in the Web Of Trust in their Transferable 207 Public Key. 209 2.2. The OPENPGPKEY RDATA wire format 211 The RDATA Wire Format consists of a single OpenPGP Transferable 212 Public Key as defined in Section 11.1 of [RFC4880]. Note that this 213 format is without ASCII armor or base64 encoding. 215 2.3. The OPENPGPKEY RDATA presentation format 217 The RDATA Presentation Format, as visible in textual zone files, 218 consists of a single OpenPGP Transferable Public Key as defined in 219 Section 11,1 of [RFC4880] encoded in base64 as defined in Section 4 220 of [RFC4648]. 222 3. Location of the OPENPGPKEY record 224 The DNS does not allow the use of all characters that are supported 225 in the "local-part" of email addresses as defined in [RFC2822] and 226 [RFC6530]. Therefore, email addresses are mapped into DNS using the 227 following method: 229 o The user name (the "left-hand side" of the email address, called 230 the "local-part" in the mail message format definition [RFC2822] 231 and the local-part in the specification for internationalized 232 email [RFC6530]) should already be encoded in UTF-8 (or its subset 233 ASCII). If it is written in another encoding it should be 234 converted to UTF-8 and then hashed using the SHA2-256 [RFC5754] 235 algorithm, with the hash truncated to 28 octets and represented in 236 its hexadecimal representation, to become the left-most label in 237 the prepared domain name. Truncation comes from the right-most 238 octets. This does not include the at symbol ("@") that separates 239 the left and right sides of the email address. 241 o The string "_openpgpkey" becomes the second left-most label in the 242 prepared domain name. 244 o The domain name (the "right-hand side" of the email address, 245 called the "domain" in RFC 2822) is appended to the result of step 246 2 to complete the prepared domain name. 248 For example, to request an OPENPGPKEY resource record for a user 249 whose email address is "hugh@example.com", an OPENPGPKEY query would 250 be placed for the following QNAME: "c93f1e400f26708f98cb19d936620da35 251 eec8f72e57f9eec01c1afd6._openpgpkey.example.com". The corresponding 252 RR in the example.com zone might look like (key shortened for 253 formatting): 255 c9[..]d6._openpgpkey.example.com. IN OPENPGPKEY 257 4. Email address variants 259 Mail systems usually handle variant forms of local-parts. The most 260 common variants are upper and lower case, often automatically 261 corrected when a name is recognized as such. Other variants include 262 systems that ignore "noise" characters such as dots, so that local 263 parts johnsmith and John.Smith would be equivalent. Many systems 264 allow "extensions" such as john-ext or mary+ext where john or mary is 265 treated as the effective local-part, and the ext is passed to the 266 recipient for further handling. This can complicate finding the 267 OPENPGPKEY record associated with the dynamically created email 268 address. 270 [RFC5321] and its predecessors have always made it clear that only 271 the recipient MTA is allowed to interpret the local-part of an 272 address. A client supporting OPENPGPKEY therefor MUST NOT perform 273 any kind of mapping rules based on the email address. 275 5. Application use of OPENPGPKEY 277 The OPENPGPKEY record allows an application or service to obtain or 278 verify an OpenPGP public key. The lookup result MUST pass DNSSEC 279 validation; if validation reaches any state other than "Secure", the 280 verification MUST be treated as a failure. 282 5.1. Obtaining an OpenPGP key for a specific email address 284 If no OpenPGP public keys are known for an email address, an 285 OPENPGPKEY lookup MAY be performed to discover the OpenPGP public key 286 that belongs to a specific email address. This public key can then 287 be used to verify a received signed message or can be used to send 288 out an encrypted email message. An application that confirms the 289 lack of an OPENPGPKEY record SHOULD remember this for some time to 290 avoid sending out a DNS request for each email message that is sent 291 out as this constitutes a privacy leak. 293 5.2. Confirming the validity of an OpenPGP key 295 Locally stored OpenPGP public keys are not automatically refreshed. 296 If the owner of that key creates a new OpenPGP public key, that owner 297 is unable to securely notify all users and applications that have its 298 old OpenPGP public key. Applications and users can perform an 299 OPENPGPKEY lookup to confirm the locally stored OpenPGP public key is 300 still the correct key to use. If verifying a locally stored OpenPGP 301 public key and the OpenPGP public key found through DNS is different 302 from the locally stored OpenPGP public key, the verification MUST be 303 treated as a failure. An application that can interact with the user 304 MAY ask the user for guidance. For privacy reasons, an application 305 MUST NOT attempt to validate a locally stored OpenPGP key using an 306 OPENPGPKEY lookup at every use of that key. 308 5.3. Verifying an unknown OpenPGP signature 310 Storage media can be signed using an OpenPGP public key. Even if the 311 OpenPGP public key is included on the storage media, it needs to be 312 independently validated. OpenPGP public keys contain one or more IDs 313 than can have the syntax of an email address. An application can 314 perform a lookup for an OPENPGPKEY at the expected location for the 315 specific email address to confirm the validity of the OpenPGP public 316 key. Once the key has been validated, all files on the storage media 317 that have been signed by this key can now be verified. 319 6. OpenPGP Key size and DNS 320 Due to the expected size of the OPENPGPKEY record, applications 321 SHOULD use TCP - not UDP - to perform queries for the OPENPGPKEY 322 Resource Record. 324 Although the reliability of the transport of large DNS Resource 325 Records has improved in the last years, it is still recommended to 326 keep the DNS records as small as possible without sacrificing the 327 security properties of the public key. The algorithm type and key 328 size of OpenPGP keys should not be modified to accommodate this 329 section. 331 OpenPGP supports various attributes that do not contribute to the 332 security of a key, such as an embedded image file. It is recommended 333 that these properties are not exported to OpenPGP public keyrings 334 that are used to create OPENPGPKEY Resource Records. Some OpenPGP 335 software, for example GnuPG, have support for a "minimal key export" 336 that is well suited to use as OPENPGPKEY RDATA. See Appendix A. 338 7. Security Considerations 340 OPENPGPKEY usage considerations are published in [OPENPGPKEY-USAGE]. 342 7.1. Response size 344 To prevent amplification attacks, an Authoritative DNS server MAY 345 wish to prevent returning OPENPGPKEY records over UDP unless the 346 source IP address has been verified with [DNS-COOKIES]. Such servers 347 MUST NOT return REFUSED, but answer the query with an empty Answer 348 Section and the truncation flag set ("TC=1"). 350 7.2. Email address information leak 352 The hashing of the user name in this document is not a security 353 feature. Publishing OPENPGPKEY records however, will create a list 354 of hashes of valid email addresses, which could simplify obtaining a 355 list of valid email addresses for a particular domain. It is 356 desirable to not ease the harvesting of email addresses where 357 possible. 359 The domain name part of the email address is not used as part of the 360 hash so that hashes can be used in multiple zones deployed using 361 DNAME [RFC6672]. This does makes it slightly easier and cheaper to 362 brute-force the SHA2-256 hashes into common and short user names, as 363 single rainbow tables can be re-used across domains. This can be 364 somewhat countered by using NSEC3. 366 DNS zones that are signed with DNSSEC using NSEC for denial of 367 existence are susceptible to zone-walking, a mechanism that allows 368 someone to enumerate all the OPENPGPKEY hashes in a zone. This can 369 be used in combination with previously hashed common or short user 370 names (in rainbow tables) to deduce valid email addresses. DNSSEC- 371 signed zones using NSEC3 for denial of existence instead of NSEC are 372 significantly harder to brute-force after performing a zone-walk. 374 7.3. Storage of OPENPGPKEY data 376 Users may have a local key store with OpenPGP public keys. An 377 application supporting the use of OPENPGPKEY DNS records MUST NOT 378 modify the local key store without explicit confirmation of the user, 379 as the application is unaware of the user's personal policy for 380 adding, removing or updating their local key store. An application 381 MAY warn the user if an OPENPGPKEY record does not match the OpenPGP 382 public key in the local key store. 384 Applications that do not have users associated with, such as daemon 385 processes, SHOULD store OpenPGP public keys obtained via OPENPGPKEY 386 up to their DNS TTL value. This avoids repeated DNS lookups that 387 third parties could monitor to determine when an email is being sent 388 to a particular user. If TLS is in use between MTA's, only the DNS 389 lookup could happen unencrypted. 391 7.4. Forward security of OpenPGP versus DNSSEC 393 DNSSEC key sizes are chosen based on the fact that these keys can be 394 rolled with next to no requirement for security in the future. If 395 one doubts the strength or security of the DNSSEC key for whatever 396 reason, one simply rolls to a new DNSSEC key with a stronger 397 algorithm or larger key size. On the other hand, OpenPGP key sizes 398 are chosen based on how many years (or decades) their encryption 399 should remain unbreakable by adversaries that own large scale 400 computational resources. 402 This effectively means that anyone who can obtain a DNSSEC private 403 key of a domain name via coercion, theft or brute force calculations, 404 can replace any OPENPGPKEY record in that zone and all of the 405 delegated child zones, irrespective of the key size of the OpenPGP 406 keypair. Any future messages encrypted with the malicious OpenPGP 407 key could then be read. 409 Therefore, an OpenPGP key obtained via an OPENPGPKEY record can only 410 be trusted as much as the DNS domain can be trusted, and is no 411 substitute for in-person key verification of the "Web of Trust". See 412 [OPENPGPKEY-USAGE] for more in-depth information on safe usage of 413 OPENPGPKEY based OpenPGP keys. 415 8. IANA Considerations 417 8.1. OPENPGPKEY RRtype 419 This document uses a new DNS RR type, OPENPGPKEY, whose value 61 has 420 been allocated by IANA from the Resource Record (RR) TYPEs 421 subregistry of the Domain Name System (DNS) Parameters registry. 423 9. Acknowledgments 425 This document is based on RFC-4255 and draft-ietf-dane-smime whose 426 authors are Paul Hoffman, Jacob Schlyter and W. Griffin. Olafur 427 Gudmundsson provided feedback and suggested various improvements. 428 Willem Toorop contributed the gpg and hexdump command options. 429 Daniel Kahn Gillmor provided the text describing the OpenPGP packet 430 formats and filtering options. Edwin Taylor contributed language 431 improvements for various iterations of this document. Text regarding 432 email mappings was taken from draft-levine-dns-mailbox whose author 433 is John Levine. 435 10. References 437 10.1. Normative References 439 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 440 Requirement Levels", BCP 14, RFC 2119, March 1997. 442 [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. 443 Rose, "DNS Security Introduction and Requirements", RFC 444 4033, March 2005. 446 [RFC4034] Arends, R., Austein, R., Larson, M., Massey, D., and S. 447 Rose, "Resource Records for the DNS Security Extensions", 448 RFC 4034, March 2005. 450 [RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S. 451 Rose, "Protocol Modifications for the DNS Security 452 Extensions", RFC 4035, March 2005. 454 [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data 455 Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, 456 . 458 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 459 Thayer, "OpenPGP Message Format", RFC 4880, DOI 10.17487/ 460 RFC4880, November 2007, 461 . 463 [RFC5754] Turner, S., "Using SHA2 Algorithms with Cryptographic 464 Message Syntax", RFC 5754, DOI 10.17487/RFC5754, January 465 2010, . 467 10.2. Informative References 469 [DNS-COOKIES] 470 Eastlake, Donald., "Domain Name System (DNS) Cookies", 471 draft-ietf-dnsop-cookies (work in progress), August 2015. 473 [HKP] Shaw, D., "The OpenPGP HTTP Keyserver Protocol (HKP)", 474 draft-shaw-openpgp-hkp (work in progress), March 2013. 476 [OPENPGPKEY-USAGE] 477 Wouters, P., "Usage considerations with the DNS OPENPGPKEY 478 record", draft-dane-openpgpkey-usage (work in progress), 479 October 2014. 481 [RFC2181] Elz, R. and R. Bush, "Clarifications to the DNS 482 Specification", RFC 2181, DOI 10.17487/RFC2181, July 1997, 483 . 485 [RFC2822] Resnick, P., Ed., "Internet Message Format", RFC 2822, DOI 486 10.17487/RFC2822, April 2001, 487 . 489 [RFC3597] Gustafsson, A., "Handling of Unknown DNS Resource Record 490 (RR) Types", RFC 3597, DOI 10.17487/RFC3597, September 491 2003, . 493 [RFC5233] Murchison, K., "Sieve Email Filtering: Subaddress 494 Extension", RFC 5233, DOI 10.17487/RFC5233, January 2008, 495 . 497 [RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321, 498 DOI 10.17487/RFC5321, October 2008, 499 . 501 [RFC6530] Klensin, J. and Y. Ko, "Overview and Framework for 502 Internationalized Email", RFC 6530, DOI 10.17487/RFC6530, 503 February 2012, . 505 [RFC6672] Rose, S. and W. Wijngaards, "DNAME Redirection in the 506 DNS", RFC 6672, DOI 10.17487/RFC6672, June 2012, 507 . 509 [RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication 510 of Named Entities (DANE) Transport Layer Security (TLS) 511 Protocol: TLSA", RFC 6698, August 2012. 513 [RFC7129] Gieben, R. and W. Mekking, "Authenticated Denial of 514 Existence in the DNS", RFC 7129, DOI 10.17487/RFC7129, 515 February 2014, . 517 Appendix A. Generating OPENPGPKEY records 519 The commonly available GnuPG software can be used to generate a 520 minimum Transferable Public Key for the RRdata portion of an 521 OPENPGPKEY record: 523 gpg --export --export-options export-minimal,no-export-attributes \ 524 hugh@example.com | base64 526 The --armor or -a option of the gpg command should NOT be used, as it 527 adds additional markers around the armored key. 529 When DNS software reading or signing the zone file does not yet 530 support the OPENPGPKEY RRtype, the Generic Record Syntax of [RFC3597] 531 can be used to generate the RDATA. One needs to calculate the number 532 of octets and the actual data in hexadecimal: 534 gpg --export --export-options export-minimal,no-export-attributes \ 535 hugh@example.com | wc -c 537 gpg --export --export-options export-minimal,no-export-attributes \ 538 hugh@example.com | hexdump -e \ 539 '"\t" /1 "%.2x"' -e '/32 "\n"' 541 These values can then be used to generate a generic record (line 542 break has been added for formatting): 544 ._openpgpkey.example.com. IN TYPE61 \# \ 545 547 The openpgpkey command in the hash-slinger software can be used to 548 generate complete OPENPGPKEY records 550 ~> openpgpkey --output rfc hugh@example.com 551 c9[..]d6._openpgpkey.example.com. IN OPENPGPKEY mQCNAzIG[...] 553 ~> openpgpkey --output generic hugh@example.com 554 c9[..]d6._openpgpkey.example.com. IN TYPE61 \# 2313 99008d03[...] 556 Author's Address 558 Paul Wouters 559 Red Hat 561 Email: pwouters@redhat.com