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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'RFC2782' is defined on line 541, but no explicit reference was found in the text ** Obsolete normative reference: RFC 5785 (Obsoleted by RFC 8615) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group W. Koch 3 Internet-Draft GnuPG e.V. 4 Intended status: Informational November 13, 2018 5 Expires: May 17, 2019 7 OpenPGP Web Key Directory 8 draft-koch-openpgp-webkey-service-07 10 Abstract 12 This specification describes a service to locate OpenPGP keys by mail 13 address using a Web service and the HTTPS protocol. It also provides 14 a method for secure communication between the key owner and the mail 15 provider to publish and revoke the public key. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on May 17, 2019. 34 Copyright Notice 36 Copyright (c) 2018 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Notational Conventions . . . . . . . . . . . . . . . . . . . 2 53 3. Web Key Directory . . . . . . . . . . . . . . . . . . . . . . 2 54 3.1. Key Discovery . . . . . . . . . . . . . . . . . . . . . . 3 55 4. Web Key Directory Update Protocol . . . . . . . . . . . . . . 5 56 4.1. The Submission Address . . . . . . . . . . . . . . . . . 7 57 4.2. The Submission Mail . . . . . . . . . . . . . . . . . . . 7 58 4.3. The Confirmation Request . . . . . . . . . . . . . . . . 7 59 4.4. The Confirmation Response . . . . . . . . . . . . . . . . 9 60 4.5. Policy Flags . . . . . . . . . . . . . . . . . . . . . . 10 61 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 62 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 63 6.1. Well-Known URI . . . . . . . . . . . . . . . . . . . . . 11 64 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 65 8. Normative References . . . . . . . . . . . . . . . . . . . . 12 66 Appendix A. Sample Protocol Run . . . . . . . . . . . . . . . . 12 67 A.1. Sample Keys . . . . . . . . . . . . . . . . . . . . . . . 13 68 A.2. Sample Messages . . . . . . . . . . . . . . . . . . . . . 13 69 Appendix B. Changes Since -06 . . . . . . . . . . . . . . . . . 17 70 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18 72 1. Introduction 74 This memo describes a method to associate OpenPGP keys with a mail 75 address and how to look them up using a web service with a well-known 76 URI. In addition a mail based protocol is given to allow a client to 77 setup such an association and to maintain it. 79 2. Notational Conventions 81 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 82 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 83 document are to be interpreted as described in [RFC2119]. 85 3. Web Key Directory 87 A major use case for OpenPGP is the encryption of mail. A common 88 difficulty of sending encrypted mails to a new communication partner 89 is to find the appropriate public key of the recipient. Unless an 90 off-channel key exchange has been done, there are no easy ways to 91 discover the required key. The common practice is to search the 92 network of public key servers for a key matching the recipient's mail 93 address. This practise bears the problem that the keyservers are not 94 able to give a positive confirmation that a key actually belongs to 95 the mail addresses given in the key. Further, there are often 96 several keys matching a mail address and thus one needs to pick a key 97 on good luck. This is clearly not a secure way to setup an end-to- 98 end encryption. Even if the need for a trusted key for an initial 99 mail message is relinquished, a non-authenticated key may be a wrong 100 one and the actual recipient would receive a mail which she can't 101 decrypt, due to the use of a wrong key. 103 Methods to overcome this problem are 105 o sending an initial unencrypted message with the public key 106 attached, 108 o using the OpenPGP DANE protocol to lookup the recipients key via 109 the DNS. 111 The first method has the obvious problems of not even trying to 112 encrypt the initial mail, an extra mail round-trip, and problems with 113 unattended key discovery. 115 The latter method works fine but requires that mail providers need to 116 set up a separate DNS resolver to provide the key. The 117 administration of a DNS zone is often not in the hands of small mail 118 installations. Thus an update of the DNS resource records needs to 119 be delegated to the ISP running the DNS service. Further, DNS 120 lookups are not encrypted and missing all confidentially. Even if 121 the participating MUAs are using STARTTLS to encrypt the mail 122 exchange, a DNS lookup for the key unnecessarily identifies the 123 local-part of the recipients mail address to any passive 124 eavesdroppers. 126 This memo specified a new method for key discovery using an encrypted 127 https connection. 129 3.1. Key Discovery 131 Although URIs are able to encode all kind of characters, 132 straightforward implementations of a key directory may want to store 133 the local-part of a mail address directly in the file system. This 134 forbids the use of certain characters in the local-part. To allow 135 for such an implementation method the URI uses an encoded form of the 136 local-part which can be directly mapped to a file name. 138 OpenPGP defines its User IDs, and thus the mail address, as UTF-8 139 strings. To help with the common pattern of using capitalized names 140 (e.g. "Joe.Doe@example.org") for mail addresses, and under the 141 premise that almost all MTAs treat the local-part case-insensitive 142 and that the domain-part is required to be compared case-insensitive 143 anyway, all upper-case ASCII characters in a User ID are mapped to 144 lowercase. Non-ASCII characters are not changed. 146 The so mapped local-part is hashed using the SHA-1 algorithm. The 147 resulting 160 bit digest is encoded using the Z-Base-32 method as 148 described in [RFC6189], section 5.1.6. The resulting string has a 149 fixed length of 32 octets. 151 There are two variants on how to form the request URI: The advanced 152 and the direct method. Implementations MUST first try the advanced 153 method. Only if the required sub-domain does not exist, they SHOULD 154 fall back to the direct method. 156 The advanced method requires a sub-domain with the fixed name 157 "openpgpkey" is created and queried. It constructs the URI from the 158 concatenation of these items: 160 o The scheme "https://", 162 o the domain-part, 164 o the string "/.well-known/openpgpkey/", 166 o the domain-part in lowercase, 168 o the string "/hu/", 170 o the above constructed 32 octet string, 172 o the unchanged local-part as a parameter with name "l" using proper 173 percent escaping. 175 An example for such an advanced method URI to lookup the key for 176 Joe.Doe@Example.ORG is: 178 https://openpgpkey.example.org/.well-known/openpgpkey/ 179 example.org/hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe 181 (line has been wrapped for rendering purposes) 183 The direct method requires no additional DNS entries and constructs 184 the URI from the concatenation of these items: 186 o The scheme "https://", 188 o the domain-part, 190 o the string "/.well-known/openpgpkey/hu/", 192 o the above constructed 32 octet string, 193 o the unchanged local-part as a parameter with name "l" using proper 194 percent escaping. 196 Example for a direct method URI: 198 https://example.org/.well-known/openpgpkey/ 199 hu/iy9q119eutrkn8s1mk4r39qejnbu3n5q?l=Joe.Doe 201 (line has been wrapped for rendering purposes) 203 The HTTP GET method MUST return the binary representation of the 204 OpenPGP key for the given mail address. The key needs to carry a 205 User ID packet ([RFC4880]) with that mail address. Note that the key 206 may be revoked or expired - it is up to the client to handle such 207 conditions. To ease distribution of revoked keys, a server may 208 return revoked keys in addition to a new key. The keys are returned 209 by a single request as concatenated key blocks. 211 The server MUST accept the HTTP HEAD method to allow a client to 212 check for the existence of a key. 214 The server SHOULD use "application/octet-stream" as the Content-Type 215 for the data but clients SHOULD also accept any other Content-Type. 216 The server MUST NOT return an ASCII armored version of the key. 218 The server MUST serve a Policy Flags file as specified below. That 219 file is even required if the Web Key Directory Update Protocol is not 220 supported. 222 The benefit of the advanced method is its greater flexibility in 223 setting up the Web Key Directory in environments where more than one 224 mail domain is hosted. DNS SRV resource records, as used in earlier 225 specifications of this protocol, posed a problem for implementations 226 which have only limited access to DNS resolvers. The direct method 227 is kept for backward compatibility and to allow providing a Web Key 228 Directory even with without DNS change requirements. 230 4. Web Key Directory Update Protocol 232 To put keys into the key directory a protocol to automate the task is 233 desirable. The protocol defined here is entirely based on mail and 234 the assumption that a mail provider can securely deliver mail to the 235 INBOX of a user (e.g. an IMAP folder). Note that the same protocol 236 may also be used for submitting keys for use with OpenPGP DANE. 238 In the following sections the term "target key" denotes the to be 239 published key, the term "submission key" the key associated with the 240 submission-address of the mail provider. The string "WELLKNOWN" 241 denotes the first part of an URI specific for a domain. In the 242 examples the domain "example.org" is assumed, thus: 244 WELLKNOWN := https://openpgpkey.example.org/.well-known/ 245 example.org/openpgpkey 247 (line has been wrapped for rendering purposes) 249 or if the sub-domain "opengpgkey" does not exist (direct method): 251 WELLKNOWN := https://example.org/.well-known/openpgpkey 253 We assume that the user already created a key for her mail account 254 alice@example.org. To install the key at her provider's Web Key 255 Directory, she performs the following steps: 257 1. She retrieves a file which contains one line with the mail 258 address used to submit the key to the mail provider. The DNS SRV 259 rules described for the Web Key Directory apply here as well. 260 See below for the syntax of that file. For a mail address at the 261 domain "example.org" the URI of the file is 263 WELLKNOWN/submission-address 265 2. She sends her key using SMTP (or any other transport mechanism) 266 to the provider using the submission address and key format as 267 specified by PGP/MIME. 269 3. The provider checks that the received key has a User ID which 270 matches an account name of the provider. 272 4. The provider sends an encrypted message containing a nonce and 273 the fingerprint of the key to the mail account of the user. Note 274 that a similar scheme is used by the well known caff(1) tool to 275 help with key signing parties. 277 5. A legitimate user will be able to decrypt the message because she 278 created the key and is in charge of the private key. This step 279 verifies that the submitted key has actually been created by the 280 owner of the account. 282 6. The user sends the decrypted nonce back to the submission address 283 as a confirmation that the private key is owned by her and that 284 the provider may now publish the key. Although technically not 285 required, it is suggested that the mail to the provider is 286 encrypted. The public key for this is retrieved using the key 287 lookup protocol described above. 289 7. The provider receives the nonce, matches it with its database of 290 pending confirmations and then publishes the key. Finally the 291 provider sends a mail back to the user to notify her of the 292 publication of her key. 294 The message data structures used for the above protocol are specified 295 in detail below. 297 4.1. The Submission Address 299 The address of the submission file is 301 WELLKNOWN/submission-address 303 The file consists of exactly one line, terminated by a LF, or the 304 sequence of CR and LF, with the full mail address to be used for 305 submission of a key to the mail provider. For example the content of 306 the file may be 308 key-submission-example.org@directory.example.org 310 4.2. The Submission Mail 312 The mail used to submit a key to the mail provider MUST comply to the 313 PGP/MIME specification ([RFC3156], section 7), which states that the 314 Content-Type must be "application/pgp-keys", there are no required or 315 optional parameters, and the body part contains the ASCII-armored 316 transferable Public Key Packets as defined in [RFC4880], section 317 11.1. 319 The mail provider MUST publish a key capable of signing and 320 encryption for the submission-address in the Web Key Directory or via 321 DANE. The key to be published MUST be submitted using a PGP/MIME 322 encrypted message ([RFC3156], section 4). The message MUST NOT be 323 signed (because the authenticity of the signing key has not yet been 324 confirmed). After decryption of the message at the mail provider a 325 single "application/pgp-keys" part, as specified above, is expected. 327 4.3. The Confirmation Request 329 The mail provider sends a confirmation mail in response to a received 330 key publication request. The message MUST be sent from the 331 submission-address of the mail provider to the mail address extracted 332 from the target key. The message needs to be a PGP/MIME signed 333 message using the submission key of the provider for the signature. 334 The signed message MUST have two parts: 336 The first part MUST have "text" as its Content-Type and can be used 337 to explain the purpose of the mail. For example it may point to this 338 RFC and explain on how to manually perform the protocol. 340 The second part MUST have "application/vnd.gnupg.wkd" if the protocol 341 version of the server is 5 or later; without a known protocol version 342 or a version less than 5, "application/vnd.gnupg.wks" MUST be used as 343 its Content-Type and carry an OpenPGP encrypted message in ASCII 344 Armor format. The message MUST be encrypted to the target key and 345 MUST NOT be signed. After decryption a text file in the Web Key data 346 format must be yielded. 348 That data format consists of name-value pairs with one name-value 349 pair per LF or CR+LF terminated line. Empty lines are allowed and 350 will be ignored by the receiver. A colon is used to terminate a 351 name. 353 In a confirmation request the following names MUST be send in the 354 specified order: 356 o "type": The value must be "confirmation-request". 358 o "sender": This is the mailbox the user is expected to sent the 359 confirmation response to. The value must match the mailbox part 360 of the "From:" address of this request. Exactly one address MUST 361 be given. 363 o "address": The value is the addr-spec part of the target key's 364 mail address. The value SHOULD match the addr-spec part of the 365 recipient's address. The value MUST be UTF-8 encoded as required 366 for an OpenPGP User ID. 368 o "fingerprint": The value is the fingerprint of the target key. 369 The fingerprint is given in uppercase hex encoding without any 370 interleaving spaces. 372 o "nonce": The value is a string with a minimum length of 16 octets 373 and a maximum length of 64 octets. The string must entirely be 374 made up of random ASCII letters or digits. This nonce will be 375 sent back to the mail provider as proof that the recipient is the 376 legitimate owner of the target-key. 378 The receiver of that message is expected to verify the outer 379 signature and disregard the entire message if it can't be verified or 380 has not been signed by the key associated with the submission 381 address. 383 After the message as been verified the receiver decrypts the second 384 part of the message, checks that the "fingerprint" matches the target 385 key, checks that the "address" matches a User ID of the target key, 386 and checks the other constrains of the request format. If any 387 constraint is not asserted, or the fingerprint or User ID do not 388 match the target key, or there is no pending publication requests 389 (i.e. a mail recently sent o the submission address), the user MAY be 390 notified about this fake confirmation attempt. 392 In other cases the confirmation request is legitimate and the MUA 393 shall silently send a response as described in the next section. 395 The rationale for the outer signature used with this request is to 396 allow early detection of spam mails. This can be done prior to the 397 decryption step and avoids asking the user to enter a passphrase to 398 perform the decryption for a non-legitimate message. The use of a 399 simple encrypted attachment, instead of using PGP/MIME encryption, is 400 to convey the Content-Type of that attachment in the clear and also 401 to prevent automatic decryption of that attachment by PGP/MIME aware 402 clients. The MUA may in fact detect this confirmation request and 403 present a customized dialog for confirming that request. 405 4.4. The Confirmation Response 407 A response to a confirmation request MUST only be send in the 408 positive case; there is no negative confirmation response. A mail 409 service provider is expected to cancel a pending key submission after 410 a suitable time without a confirmation. The mail service provider 411 SHOULD NOT retry the sending of a confirmation request after the 412 first request has been send successfully. 414 The user MUST send the confirmation response from her target mail 415 address to the "from" address of the confirmation request. The 416 message MUST be signed and encrypted using the PGP/MIME Combined 417 format ([RFC3156], section 6.2). The signing key is the target key 418 and the encryption key is the key associated with the provider's 419 submission address. 421 The Content-Type used for the plaintext message MUST match the 422 Content-Type of the request. The format is the same as described 423 above for the Confirmation Request. The body must contain three 424 name-value pairs in this order: 426 o "type": The value must be "confirmation-response". 428 o "sender": The value must match the mailbox part of the "From:" 429 address of this response. Exactly one address MUST be given. 431 o "nonce": The value is the value of the "nonce" parameter from the 432 confirmation request. 434 4.5. Policy Flags 436 For key generation and submission it is useful to tell the client 437 about certain properties of the mail provider in advance. This can 438 be done with a file at the URL 440 WELLKNOWN/policy 442 A site supporting the Web Key Directory MUST serve this file; it is 443 sufficient if that file has a zero length. Clients may use this file 444 to check for Web Key Directory support. 446 The file contains keywords and optionally values, one per line with 447 each line terminated by a LF or the sequence of CR and LF. Empty 448 lines and lines starting with a '#' character are considered comment 449 lines. A keyword is made up of lowercase letters, digits, hyphens, 450 or dots. An underscore is allowed as a name space delimiters; see 451 below. The first character must be a letter. Keywords which are 452 defined to require a value are directly followed by a colon and then 453 after optional white space the value. Clients MUST use case- 454 insensitive matching for the keyword. 456 Currently defined keywords are: 458 o "mailbox-only": The mail server provider does only accept keys 459 with only a mailbox in the User ID. In particular User IDs with a 460 real name in addition to the mailbox will be rejected as invalid. 462 o "dane-only": The mail server provider does not run a Web Key 463 Directory but only an OpenPGP DANE service. The Web Key Directory 464 Update protocol is used to update the keys for the DANE service. 466 o "auth-submit": The submission of the mail to the server is done 467 using an authenticated connection. Thus the submitted key will be 468 published immediately without any confirmation request. 470 o "protocol-version": This keyword can be used to explicitly claim 471 the support of a specific version of the Web Key Directory update 472 protocol. This is in general not needed but implementations may 473 have workarounds for providers which only support an old protocol 474 version. If these providers update to a newer version they should 475 add this keyword so that the implementation can disable the 476 workaround. The value is an integer corresponding to the 477 respective draft revision number. 479 o "submission-address": An alternative way to specify the submission 480 address. The value is the addr-spec part of the address to send 481 requests to this server. If this keyword is used in addition to 482 the "submission-address" file, both MUST have the same value. 484 More keywords will be defined in updates to this I-D. There is no 485 registry except for this document. For experimental use of new 486 features or for provider specific settings, keywords MUST be prefixed 487 with a domain name and an underscore. 489 5. Security Considerations 491 The use of SHA-1 for the mapping of the local-part to a fixed string 492 is not a security feature but merely used to map the local-part to a 493 fixed-sized string made from a well defined set of characters. It is 494 not intended to conceal information about a mail address. 496 The domain name part of the mail address is not part of the hash to 497 avoid problems with internationalized domain names. Instead a 498 separate URL is required for each domain name. 500 The use of DNS SRV records reduces the certainty that a mail address 501 belongs to a domain. For example an attacker may change the target 502 to a host in a sub-domain under their control and thus gain full 503 control over all keys. An implementation may want to weight the 504 certainty of a mapping different if it has been retrieved via a sub- 505 domain and in particular if a non-recommended name is used for the 506 sub-domain. 508 To make it a bit harder to test for published keys, the server 509 responsible to serve the WELLKNOWN directory SHOULD NOT create an 510 index file for that directory or any sub-directory. 512 The mail provider MUST make sure to filter a key in a way that only 513 the User ID belonging to that user is returned and that confirmation 514 requests are only send for such User IDs. It is further recommended 515 that a client filters the key for a publication requests so that only 516 a key with the specific User ID of the provider is send. 518 6. IANA Considerations 520 6.1. Well-Known URI 522 IANA is requested to assign a well-known URI in the "Well-Known URIs" 523 registry as defined by [RFC5785]: 525 URI suffix: openpgpkey 526 Change controller: IETF 528 Specification document: This 530 7. Acknowledgments 532 The author would like to acknowledge the help of the individuals who 533 kindly voiced their opinions on the GnuPG mailing lists, in 534 particular, the help of Bernhard Reiter and Guilhem Moulin. 536 8. Normative References 538 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 539 Requirement Levels", BCP 14, RFC 2119, March 1997. 541 [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 542 specifying the location of services (DNS SRV)", RFC 2782, 543 DOI 10.17487/RFC2782, February 2000, . 546 [RFC3156] Elkins, M., Del Torto, D., Levien, R., and T. Roessler, 547 "MIME Security with OpenPGP", RFC 3156, August 2001. 549 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., Shaw, D., and R. 550 Thayer, "OpenPGP Message Format", RFC 4880, November 2007. 552 [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known 553 Uniform Resource Identifiers (URIs)", RFC 5785, DOI 554 10.17487/RFC5785, April 2010, 555 . 557 [RFC6189] Zimmermann, P., Johnston, A., Ed., and J. Callas, "ZRTP: 558 Media Path Key Agreement for Unicast Secure RTP", RFC 559 6189, DOI 10.17487/RFC6189, April 2011, 560 . 562 Appendix A. Sample Protocol Run 564 The following non-normative example can be used by implementors as 565 guidance. 567 Note that GnuPG version 2.1.12 supports the key discovery described 568 in version -00 of this document (auto-key-locate method "wkd"). 569 Version 2.1.16 can run the protocol described in this document but is 570 also able to run the protocol version specified by -01. For backward 571 compatibility this example uses the Content-Type as required for 572 versions of this protocol prior to -04; if the client knows that the 573 server support -04 "vnd.gnupg.wkd" should be used. 575 A.1. Sample Keys 577 This is the provider's submission key: 579 -----BEGIN PGP PRIVATE KEY BLOCK----- 581 lFgEV/TAohYJKwYBBAHaRw8BAQdAB/k9YQfSTI8qQqqK1KimH/BsvzsowWItSQPT 582 FP+fOC4AAP46uJ3Snno3Vy+kORye3rf0VvWvuz82voEQLxG6WpfHhREEtBprZXkt 583 c3VibWlzc2lvbkBleGFtcGxlLm5ldIh5BBMWCAAhBQJX9MCiAhsDBQsJCAcCBhUI 584 CQoLAgQWAgMBAh4BAheAAAoJEKhtNooW0cqEWMUA/0e9XaeptszWC9ZvPg8INL6a 585 BvRqPBYGU7PGmuXsxBovAQDyckOykG0UAfHVyN1w4gSK/biMcnqVr857i8/HuvjW 586 C5xdBFf0wKISCisGAQQBl1UBBQEBB0Apvaoe4MtSEJ1fpds/4DFl2kXXBpnVji/s 587 Wg9btdthNQMBCAcAAP9FJX99T1LEJzBnvBBnc6bimnT6/1OKM9RdO4R0/uVP6BFL 588 iGEEGBYIAAkFAlf0wKICGwwACgkQqG02ihbRyoTlGwD9FBr92osjL7HkhhZZ7Z2D 589 My3b9zpoZeMjvPg5YPqpdKMA/jhZoHuZCRMBYf7YRFb8aXtuyetDFZYrkjnum+OG 590 HFAD 591 =Hnwd 592 -----END PGP PRIVATE KEY BLOCK----- 594 This is the target key to be published: 596 -----BEGIN PGP PRIVATE KEY BLOCK----- 598 lFgEV2o9XRYJKwYBBAHaRw8BAQdAZ8zkuQDL9x7rcvvoo6s3iEF1j88Dknd9nZhL 599 nTEoBRkAAP94nCZMM4WY2IORXfM6phLGSz3RsHvs/vA1Opaus4+R3BKJtBtwYXRy 600 aWNlLmx1bXVtYmFAZXhhbXBsZS5uZXSIeQQTFggAIQUCV2o9XQIbAwULCQgHAgYV 601 CAkKCwIEFgIDAQIeAQIXgAAKCRATlWNoKgINCpkNAQDFDcwJUzsxu7aJUiPdpYXj 602 4uVarrXakxEE8mGFotWhLAD9GH4rqLDYIE3NKEU0s+Okt4tEIwJaV8H1NNPPPMiK 603 3g2cXQRXaj2NEgorBgEEAZdVAQUBAQdAFnnmZc99TuKk5iCq9wmYZUVF2RcXN2Cs 604 qAl8iGQQUWsDAQgHAAD/VN/VGmlcwGBPcLTya2hfU4t37nMcFCKdNSXjJ5DFA0AP 605 PohhBBgWCAAJBQJXaj2NAhsMAAoJEBOVY2gqAg0Ky4UA/0GmVaXzXemLvv1Xw4yx 606 Eaz/KfKKGc4RJ+38fyqUzw8NAQCohQ+ki3I5f84EXLZEiUiLsnVtOn1HNxvND/gW 607 TiFZBA== 608 =GHi7 609 -----END PGP PRIVATE KEY BLOCK----- 611 A.2. Sample Messages 613 The first message triggeres the publication requests. 615 From: patrice.lumumba@example.net 616 To: key-submission@example.net 617 Subject: Key publishing request 618 MIME-Version: 1.0 619 Content-Type: multipart/encrypted; 620 protocol="application/pgp-encrypted"; 621 boundary="=-=01-e8k41e11ob31eefa36wo=-=" 622 Date: Wed, 05 Oct 2016 10:15:51 +0000 624 --=-=01-e8k41e11ob31eefa36wo=-= 625 Content-Type: application/pgp-encrypted 627 Version: 1 629 --=-=01-e8k41e11ob31eefa36wo=-= 630 Content-Type: application/octet-stream 632 -----BEGIN PGP MESSAGE----- 634 hF4DUgLY5tvmW2sSAQdAR1AcqvFpQe/fHRZbf0xcnl9Tb+AtwaX2yZnZXGELGHsw 635 1/e3E0JptwM5tpRAVe71ooF8Zq4jl76ZgQKfj/SyjpLJxyoEDy2N5wTQaqW4JtML 636 0ukB1vh7dIRDxBJX/LQIJC0wz8o1Q3vjcLJKFFvDb7YrerABpPIzwOAupcgIbQHj 637 5m1+2WU5CL8ffyJy2h1jV2X4OnvWF1Sn6J6SVD6DfZpOPRt9TxSemJrN1LJ3lG0N 638 ts8AuYmCOeC1H2r5TYyxqkC98JF8+Nvyxd/fwne8IOjK9uixkNMC5H9/ZOH0YWCb 639 wBnNB4iXuym4OIPxiLkDymsVF0ww/XrODE9Y259EGmO45VFNrJAX3HFs9/PcMCVk 640 n2qMyEkr8LHiXeEPun6Z54RHUPYv2cUkEZ0hhSJ+rtBxkc/5D/cAScCEXRKFSKEF 641 jLJAvLK/u/ga5DAzVai+vh6b6Bq+YVPaD9GWMhWj4CgR90p9LULi6S/Hzwhv9Wzf 642 8fJoJOaDjyvRDgr09jYLWamxkS9NWxqwy6MXJvxwbNdd5XtqiW4Y4o0Ll1hDJhxR 643 ljn/XvotXKwhKN+4QGhIXDVt4Dl4XxS5ptWfVTau8W8DYqDsU2obEcfsirZv53M1 644 Q9FCD8CD9+dkBt8VAJekCWVhEltcRHxlrznbk2jxm93xSD2o6gZ5X0VSaSUXyEhm 645 J+8F3gyTHGgbq/TgyjFoockWh5EtGgAFuWvmPJCF5PO/UaNeoKwgwSJBu6oTXkHx 646 R4nvvMRcj5UgTsKpZ79NiDQukbjG5ScNT5TCUiiZsBXBqBx3fD61EH6cAuh4P3Kr 647 iM7PY4fwAHo890Dx+Qlt 648 =WIhx 649 -----END PGP MESSAGE----- 651 --=-=01-e8k41e11ob31eefa36wo=-=-- 653 The server decrypts this message to 654 Content-Type: application/pgp-keys 656 -----BEGIN PGP PUBLIC KEY BLOCK----- 658 mDMEV2o9XRYJKwYBBAHaRw8BAQdAZ8zkuQDL9x7rcvvoo6s3iEF1j88Dknd9nZhL 659 nTEoBRm0G3BhdHJpY2UubHVtdW1iYUBleGFtcGxlLm5ldIh5BBMWCAAhBQJXaj1d 660 AhsDBQsJCAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEBOVY2gqAg0KmQ0BAMUNzAlT 661 OzG7tolSI92lhePi5VqutdqTEQTyYYWi1aEsAP0YfiuosNggTc0oRTSz46S3i0Qj 662 AlpXwfU00888yIreDbg4BFdqPY0SCisGAQQBl1UBBQEBB0AWeeZlz31O4qTmIKr3 663 CZhlRUXZFxc3YKyoCXyIZBBRawMBCAeIYQQYFggACQUCV2o9jQIbDAAKCRATlWNo 664 KgINCsuFAP9BplWl813pi779V8OMsRGs/ynyihnOESft/H8qlM8PDQEAqIUPpIty 665 OX/OBFy2RIlIi7J1bTp9RzcbzQ/4Fk4hWQQ= 666 =qRfF 667 -----END PGP PUBLIC KEY BLOCK----- 669 and returns this confirmation request 670 From: key-submission@example.net 671 To: patrice.lumumba@example.net 672 Subject: Confirm your key publication 673 MIME-Version: 1.0 674 Content-Type: multipart/encrypted; 675 protocol="application/pgp-encrypted"; 676 boundary="=-=01-wrzqued738dfx4x97u7y=-=" 677 Date: Wed, 05 Oct 2016 10:16:57 +0000 679 --=-=01-wrzqued738dfx4x97u7y=-= 680 Content-Type: application/pgp-encrypted 682 Version: 1 684 --=-=01-wrzqued738dfx4x97u7y=-= 685 Content-Type: application/octet-stream 687 -----BEGIN PGP MESSAGE----- 689 hF4DkYWHjk/NdMASAQdAluQeqhECpU2T0zEyBAEbFzhLkpubN160wjkFCrtUc0Mw 690 FwYgM2fp9cvTMdJ/xjkvmAcIEOT4AY/hn1yFQ4z0KG0gCkSac+8mkDylnPdxlXYw 691 0sBSAXlbqpVA7eUpFuU2Zs10zbIXxlwe6osR5wUIJut/RCOsYQmfvxC55x8mUX5/ 692 zgTnNzlMzye5ws4pTgAeQm2x0Yv018L8IZgY5KxwJLBzlss0wLZ45ZcS80hR11Fx 693 NCow1fKF8lMnOJxagTEOih807nctz8vT5bR1gx0d7N3LM+th8nAg9/6Ghf1XTpLo 694 MzwGW0FtOG7Dg1Uxbw2bjaOuRBeh6IIpmNAw1pmIfnNu7PpoRydU5w1K/R8MT06z 695 MKdJ7IW5mVGes9EGnG3e4mjuILvNaZhfYy+a73IhDSaPm3oqdl1Qx7tbNg6lGjn6 696 KStCYAcPGPp3m7aWkfsPGThOVRhEXqaFFywfwSVEj1pdIRjDFA== 697 =Cdjh 698 -----END PGP MESSAGE----- 700 --=-=01-wrzqued738dfx4x97u7y=-=-- 702 The client decrypts the attachment as 704 Content-Type: application/vnd.gnupg.wks 705 Content-Transfer-Encoding: 8bit 707 type: confirmation-request 708 sender: key-submission@example.net 709 address: patrice.lumumba@example.net 710 fingerprint: B21DEAB4F875FB3DA42F1D1D139563682A020D0A 711 nonce: f5pscz57zj6fk11wekk8gx4cmrb659a7 713 creates this response 714 Content-Type: application/vnd.gnupg.wks 715 Content-Transfer-Encoding: 8bit 717 type: confirmation-response 718 sender: key-submission@example.net 719 address: patrice.lumumba@example.net 720 nonce: f5pscz57zj6fk11wekk8gx4cmrb659a7 722 and sends it encrypted to the server 724 From: patrice.lumumba@example.net 725 To: key-submission@example.net 726 Subject: Key publication confirmation 727 MIME-Version: 1.0 728 Content-Type: multipart/encrypted; 729 protocol="application/pgp-encrypted"; 730 boundary="=-=01-iacqg4og4pqz11a5cg1o=-=" 731 Date: Wed, 05 Oct 2016 10:18:52 +0000 733 --=-=01-iacqg4og4pqz11a5cg1o=-= 734 Content-Type: application/pgp-encrypted 736 Version: 1 738 --=-=01-iacqg4og4pqz11a5cg1o=-= 739 Content-Type: application/octet-stream 741 -----BEGIN PGP MESSAGE----- 743 hF4DUgLY5tvmW2sSAQdAnB1C3PMjS4AsGU0qaCqBdWQO5i6blWEyZrEsY+JZY1Qw 744 ooNq7zdVWOHhL9LPGAALAgoL3Qfz+dN2u5QamSQ/LJ2c8M0XipNs3lqlNH63yQN1 745 0sAmAc3W8xkwul+rf6OLK/gMi6WzM4fnUhd4D1LJGIJoNUN0l3636C7ecOt2lkMl 746 5bVAYg/SyMT3ymyfQnvtiem2T5DSnPsS1g6n6QNXWvkqvX9yGxNsNDJEHTuGJB8k 747 OJoRlfWQTEo6pgA89febWl1EdeM1pPLstQ2uZE8NPjXoY1nMxAlu+iPYsR41/4sg 748 dqwOv5BPLh/GIat8hh9SPWCA9iKlgSQ/EIv5DpjQogEzpriT55dkgfvSVYIAcOdO 749 ShZ91YKkcZffevdY72omqTk10a1SUXehPooIlRFmroDsi3VDaRKrUIo= 750 =7uve 751 -----END PGP MESSAGE----- 753 --=-=01-iacqg4og4pqz11a5cg1o=-=-- 755 Appendix B. Changes Since -06 757 o Specify the advanced method with the openpgpkey sub-domain. 759 o Specify the l=LOCAL-PART query parameter. 761 o Require the provider to filter the key for publication. 763 o Drop the use of DNS SRV records. 765 Author's Address 767 Werner Koch 768 GnuPG e.V. 769 Rochusstr. 44 770 40479 Duesseldorf 771 Germany 773 Email: wk@gnupg.org 774 URI: https://gnupg.org/verein