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'AS3') ** Downref: Normative reference to an Informational RFC: RFC 6017 (ref. 'EDIINT FEATURE') ** Obsolete normative reference: RFC 2246 (Obsoleted by RFC 4346) ** Obsolete normative reference: RFC 2253 (Obsoleted by RFC 4510, RFC 4514) ** Obsolete normative reference: RFC 2828 (Obsoleted by RFC 4949) ** Obsolete normative reference: RFC 3023 (Obsoleted by RFC 7303) ** Obsolete normative reference: RFC 3280 (ref. 'PROFILE') (Obsoleted by RFC 5280) Summary: 9 errors (**), 0 flaws (~~), 7 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Individual Submission K. Meadors 3 Internet-Draft Drummond Group Inc. 4 Intended status: Informational D. Moberg 5 Axway, Inc. 6 Expires: May 2011 December 2010 8 Certificate Exchange Messaging for EDIINT 9 draft-meadors-certificate-exchange-12.txt 10 Abstract 12 The EDIINT AS1, AS2 and AS3 message formats do not currently contain 13 any neutral provisions for transporting and exchanging trading 14 partner profiles or digital certificates. EDIINT Certificate Exchange 15 Messaging provides the format and means to effectively exchange 16 certificates for use within trading partner relationships. The 17 messaging consists of two types of messages, Request and Response, 18 which allow trading partners to communicate certificates, their 19 intended usage and their acceptance through XML. Certificates can be 20 specified for use in digital signatures, data encryption or SSL/TLS 21 over HTTP (HTTPS). 23 Status of this Memo 25 This Internet-Draft is submitted to IETF in full conformance with 26 the provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on June 10, 2011. 40 Copyright Notice 42 Copyright (c) 2010 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 This document may contain material from IETF Documents or IETF 56 Contributions published or made publicly available before November 57 10, 2008. The person(s) controlling the copyright in some of this 58 material may not have granted the IETF Trust the right to allow 59 modifications of such material outside the IETF Standards Process. 60 Without obtaining an adequate license from the person(s) controlling 61 the copyright in such materials, this document may not be modified 62 outside the IETF Standards Process, and derivative works of it may 63 not be created outside the IETF Standards Process, except to format 64 it for publication as an RFC or to translate it into languages other 65 than English. 67 Conventions used in this document 69 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 70 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 71 document are to be interpreted as described in RFC-2119. 73 Table of Contents 75 1. Introduction...................................................3 76 1.1 Overview...................................................3 77 1.2 Terminology and Key Word Convention........................4 78 1.3 Certificate Lifecycle......................................5 79 1.4 Certificate Exchange Process...............................6 80 2. Message Processing.............................................7 81 2.1 Message Structure..........................................7 82 2.2 EDIINT Features Header.....................................9 83 2.3 Certificate Exchanging.....................................9 84 2.4 Certificate Implementation................................10 85 2.5 CEM Response..............................................12 86 3. CEM XML Schema Description....................................13 87 3.1 EDIINTCertificateExchangeRequest element..................13 88 3.2 EDIINTCertificateExchangeResponse element.................17 89 4. Use Case Scenario.............................................18 90 5. Profile Exchange Messaging....................................20 91 6. Implementation Considerations.................................21 92 7. Future Considerations for CEM I-D.............................21 93 8. Security Considerations.......................................21 94 9. IANA Considerations...........................................22 95 10. References...................................................22 96 10.1 Normative References.....................................22 97 10.2 Informative References...................................23 98 11. Acknowledgments..............................................23 99 Author's Addresses...............................................23 100 Appendix.........................................................24 101 A.1 EDIINT Certificate Exchange XML Schema....................24 102 A.2 Example of EDIINT Certificate Exchange Request XML........27 103 A.3 Example of EDIINT Certificate Exchange Response XML.......28 104 Changes from Previous Versions...................................28 105 B.1 Updates from Version 00...................................28 106 B.2 Updates from Version 01...................................29 107 B.3 Updates from Version 02...................................29 108 B.4 Updates from Version 03...................................29 109 B.5 Updates from Version 04...................................29 110 B.6 Updates from Version 05...................................29 111 B.7 Updates from Version 06/07/08/09/10.......................29 113 1. 114 Introduction 116 1.1 117 Overview 119 The growth and acceptance of EDIINT protocols, AS1, AS2 and AS3, in 120 numerous supply-chains was due in part to the security feature which 121 was provided. The security is not possible without the digital 122 certificates which enable it. To maintain the level of security 123 necessary to transmit business documentation, existing certificates 124 must occasionally be replaced and exchanged with newer ones. The 125 exchanging of digital certificates is unavoidable given how 126 certificates can expire or become compromised. Complicating this is 127 supply-chains which cannot afford to shutdown their business 128 transactions while trading partners laboriously upload new 129 certificates. Certificate exchange must be accomplished in a reliable 130 and seamless format so as not to affect ongoing business 131 transactions. 133 This document describes how EDIINT products may exchange public-key 134 certificates. Since EDIINT is built upon the security provided by 135 public-private key pairs, it is vital that implementers are able to 136 update their trading partners with new certificates as their old 137 certificates expire, become outdated or insecure. Certificate 138 Exchange Messaging (CEM) described here utilizes XML data to exchange 139 the certificate and provide information on its intended usage and 140 acceptance within the trading partner relationship. There are two 141 types of CEM messages. The CEM Request which presents the new 142 certificate to be introduced into the trading partner relationship 143 and the CEM Response which is the recipient's response to the CEM 144 Request. CE messages can be exchanged through AS1 [AS1], AS2 [AS2] or 145 AS3 [AS3] message transports. However, it is possible to leverage CE 146 messaging through other transport standards besides EDIINT. 148 1.2 149 Terminology and Key Word Convention 151 [RFC2828] provides a glossary of Internet security terms, and several 152 of their definitions are listed here verbatim. However, some 153 definitions required for this document were undefined by [RFC2828] or 154 rewritten to better explain their specific use within CEM. 156 Certificate - A digital certificate contains the owner's (End 157 Entity's) name, the issuer's name, a serial number, expiration date, 158 and a copy of the owner's Public Key. The Public Key is used for 159 Encrypting messages and Verifying Signatures (verifying a signature 160 is also called Authentication). 162 Certificate Revocation List (CRL) - A data structure that enumerates 163 digital certificates that have been invalidated by their issuer prior 164 to when they were scheduled to expire. [RFC2828] 166 Certification Authority (CA) - An entity that issues digital 167 certificates (especially X.509 certificates) and vouches for the 168 binding between the data items in a certificate. [RFC2828] 170 CA Certificate - A certificate issued by a trusted certification 171 authority. CA certificates are not used to encrypt data but to sign 172 other certificates. CA certificates are signed by themselves, but are 173 not considered self-signed certificates for the purpose of this 174 document. 176 Certification Hierarchy - In this structure, one CA is the top CA, 177 the highest level of the hierarchy. The top CA may issue public-key 178 certificates to one or more additional CAs that form the second 179 highest level. Each of these CAs may issue certificates to more CAs 180 at the third highest level, and so on. The CAs at the second-lowest 181 of the hierarchy issue certificates only to non-CA entities, called 182 "end entities" that form the lowest level. Thus, all certification 183 paths begin at the top CA and descend through zero or more levels of 184 other CAs. All certificate users base path validations on the top 185 CA's public key. [RFC2828] 187 CEM Request - The EDIINT Certificate Exchange Messaging (CEM) Request 188 is one of two possible CEM messages. It presents a certificate to be 189 introduced into the trading partner relationship along with relevant 190 information on how it is to be implemented. 192 CEM Response - The EDIINT Certificate Exchange Messaging (CEM) 193 Response is one of two possible CEM messages. It is the response to 194 the CEM Request indicating whether or not the end entity certificate 195 present in the CEM Request was accepted. 197 End Entity - A system entity that is the subject of a public-key 198 certificate and that is using, or is permitted and able to use, the 199 matching private key only for a purpose or purposes other than 200 signing a digital certificate; i.e., an entity that is not a CA. 201 [RFC2828] 203 End Entity Certificate - A certificate which is used to encrypt data 204 or authenticate a signature. (The private key associated with the 205 certificate is used to decrypt data or sign data). The certificate 206 may be self-signed or issued by a trusted certificate. 208 Intermediary Certificate - A certificate issued by a CA certificate 209 which itself issues another certificate (either intermediary or end 210 entity). Intermediary certificates are not used to encrypt data but 211 to sign other certificates. 213 Public Key - The publicly-disclosable component of a pair of 214 cryptographic keys used for asymmetric cryptography. [RFC2828] 216 Public Key Certificate - A digital certificate that binds a system 217 entity's identity to a public key value, and possibly to additional 218 data items. [RFC2828] 220 Self-signed Certificate - A certificate which is issued by itself 221 (both issuer and subject are the same) and is an End Entity 222 certificate. 224 1.3 225 Certificate Lifecycle 227 A certificate has five states. 229 1. Pending - Upon receiving a certificate from a trading partner, the 230 certificate is marked as Pending until a decision can be made to 231 trust it or if its validity period has not yet begun. 232 2. Rejected - If a Pending certificate is not trusted, it is 233 considered Rejected. 234 3. Accepted - Once a Pending certificate has been trusted, it is 235 considered Accepted. An Accepted certificate may be used in 236 secure transactions. 237 4. Expired - A certificate which is no longer valid because its 238 expiration date has passed. Expired certificates SHOULD be kept 239 in a certificate storehouse for decrypting and validating past 240 transactions. 241 5. Revoked - A certificate which has been explicitly revoked by its 242 owner or the certificate authority. 244 1.4 245 Certificate Exchange Process 247 This section describes a process whereby a company can distribute 248 certificates to its partners, and the company and its partners can 249 put the certificates into use. Later sections describe the specific 250 CEM protocol, which is an implementation of this process. 252 The exchange process can be used even when CEM is not useable, for 253 example, when the transport protocols or installed software systems 254 do not support CEM. It is RECOMMENDED that this process be followed 255 in distributing certificates. 257 The company that owns the certificates initiates the process. For a 258 certificate that is to be used (by the partners) to encrypt messages, 259 the initiator first prepares his system to decrypt messages that are 260 encrypted with this certificate. The initiator must also be able to 261 decrypt messages using the old certificate. The initiator company 262 distributes the new certificates by some means. The distribution MUST 263 describe the purposes of the certificates and MAY contain a respond 264 by date, the date when the distributor expects to put the 265 certificates in use. The respond by date SHOULD be present for 266 certificates that are used to sign messages or to authenticate 267 TLS/SSL connections. 269 When a partner receives a certificate, the partner should 270 authenticate the distribution message by some means. (CEM provides 271 for automatic authentication. Partners can use manual methods, 272 either with or without CEM.) 274 When a partner receives a certificate for use in encrypting messages 275 and has authenticated the certificate, the partner SHOULD begin 276 using that certificate to encrypt messages. The initiator MUST be 277 prepared to receive messages encrypted with either the old or new 278 certificate. 280 When a partner receives a certificate for use in digitally signing 281 messages or for TLS/SSL authentication and has authenticated the 282 certificate, the partner MUST prepare his system to accept messages 283 that are signed or authenticated with the new certificate. The 284 partner MUST also accept messages signed or authenticated with the 285 old certificate. 287 The partner MAY return a response to the initiator, indicating that 288 the partner has accepted the new certificate and put it in use. The 289 initiator can use these responses to track which partners are ready 290 to use the new certificate. 292 When the partner has sent a response indicating acceptance of the new 293 certificate, or when the respond by date has passed, the initiator 294 can begin using the new certificate to digitally sign messages or 295 authenticate TLS/SSL messages. The initiator MUST NOT sign or 296 authenticate messages with the new certificate until the partner has 297 accepted it or until the respond by date has passed. The initiator 298 MAY wait until the respond by date or until all partners have 299 accepted. The partners MUST accept messages signed or authenticated 300 with either the old or new certificate. 302 When the process is fully automated, it is not necessary to have a 303 specific time when both the initiator and partners switch to the new 304 certificate. 306 The initiator MUST be able to decrypt messages with both the old and 307 new certificates as soon as the new certificates are distributed. 308 The partners MUST be able to accept messages signed or TLS/SSL 309 authenticated with either the old or new certificates after they have 310 accepted the new certificate. The initiator SHOULD allow a 311 reasonable time after distributing a new signing or authenticating 312 certificate before putting it in use, so that partners have time to 313 authenticate the new certificate and prepare their systems for it. 315 For a certificate used to digitally sign messages or authenticate 316 TLS/SSL messages, there must be some way for the initiator to know 317 when partners are ready to receive the certificate. For example, this 318 may be a response from the partners, an explicit respond by date in 319 the initial distribution, an implied respond by date based on partner 320 agreements, or the expiration date of the old certificate. For a 321 certificate used to encrypt messages, the respond by date and 322 responses are less important, but responses may be useful to track 323 partners' acceptances. 325 2. 326 Message Processing 328 2.1 329 Message Structure 331 CEM messages use the underlying EDIINT transport, such as AS2, to 332 communicate information on the certificate, its intended use and its 333 acceptance. Both digital certificates and the XML data describing 334 their intended use are stored within a multipart/related MIME 335 envelope [RFC2387]. For the CEM Request message, the certificates are 336 stored in certificate chains through SMIME, certs-only MIME envelope 337 [3851], and processing information is XML data which is identified 338 through the MIME content-type of application/ediint-cert- 339 exchange+xml. The format for a CEM Request message is as follows: 341 Various EDIINT headers 342 Disposition-Notification-To: http://10.1.1.1:80/exchange/as2-company 343 Content-Type: multipart/signed; micalg=sha1; 344 protocol="application/pkcs7-signature"; 345 boundary="--OUTER-BOUNDARY" 347 ----OUTER-BOUNDARY 348 Content-Type: multipart/related; type="application/ediint-cert- 349 exchange+xml"; boundary="--INNER-BOUNDARY" 351 ----INNER-BOUNDARY 352 Content-Type: application/ediint-cert-exchange+xml 353 Content-ID: <20040101-1.alpha@example.org> 355 [CEM XML data] 356 ----INNER-BOUNDARY 357 Content-Type: application/pkcs7-mime; smime-type=certs-only 358 Content-ID: <20040101-2.alpha@example.org> 360 [digital certificate] 361 ----INNER-BOUNDARY-- 363 ----OUTER-BOUNDARY 364 Content-Type: application/pkcs7-signature 366 [Digital Signature] 367 ----OUTER-BOUNDARY-- 369 One and only one MIME type of application/ediint-cert-exchange+xml 370 MUST be present in the multipart/related structure, and it MUST be 371 the root element. Multiple certs-only media types may be included, 372 but at least one MUST be present. A unique content-id header MUST be 373 present within each of the multipart structures. 375 For the CEM Response message, a multipart/related MIME structure is 376 also used. However, no certificates are present in a CEM Response, 377 and the multipart/related structure only contains one MIME type of 378 application/ediint-cert-exchange+xml. The format for a CEM Request 379 message is as follows: 381 Various EDIINT headers 382 Disposition-Notification-To: http://10.1.1.1:80/exchange/as2-company 383 Content-Type: multipart/signed; micalg=sha1; 384 protocol="application/pkcs7-signature"; 385 boundary="--OUTER-BOUNDARY" 387 ----OUTER-BOUNDARY 388 Content-Type: multipart/related; type="application/ediint-cert- 389 exchange+xml"; boundary="--INNER-BOUNDARY" 391 ----INNER-BOUNDARY 392 Content-Type: application/ediint-cert-exchange+xml 393 Content-ID: <20040201-1.alpha@example.org> 395 [CEM XML data] 396 ----INNER-BOUNDARY-- 398 ----OUTER-BOUNDARY 399 Content-Type: application/pkcs7-signature 401 [Digital Signature] 402 ----OUTER-BOUNDARY-- 403 If possible, both the CEM Request and CEM Response message SHOULD be 404 signed. Applying digital signatures will allow for automatic exchange 405 based on a previous trust relationship. However, it may not be 406 possible in the initial exchange of a new trading partner. If a CEM 407 message is signed, the signing certificate MUST be included in the 408 digital signature. Extra security such as applying data encryption or 409 compression is OPTIONAL. Also, CEM messages SHOULD request a MDN and 410 SHOULD request a signed MDN. The MDN can be either synchronous or 411 asynchronous. All necessary headers MUST be applied to the message 412 per the underlying transport standard. 414 2.2 415 EDIINT Features Header 417 To indicate support for CEM, an EDIINT application MUST use the 418 EDIINT Features header [EDIINT-FEATURE]. The Feature Header indicates 419 the instance application can support various features, such as 420 certification exchange. The header is present in all messages from 421 the instance application, not just those which feature certification 422 exchange. 424 For applications implementing certification exchange, the CEM- 425 Feature-Name MUST be used within the EDIINT Features header: 427 CEM-Feature-Name = "CEM" 429 An example of the EDIINT Features header in a CEM Message: 431 EDIINT-Features: CEM 433 2.3 434 Certificate Exchanging 436 After obtaining the desired certificate, the initiator of the 437 certificate exchange transmits the end-entity certificate in the CEM 438 Request message. If the end-entity certificate is not self-signed, 439 then the CA certificate and any other certificates needed to create 440 the chain of trust for the end-entity certificate MUST be included in 441 the CEM Request message. Multiple end-entity certificates MAY also be 442 present. 444 The entire certificate trust chain is stored in a BER encoded P7C 445 format [REFERENCE LIKELY NEEDED] and placed within the SMIME certs- 446 only MIME envelope which is then stored in a single part of the 447 multipart/related structure. Each P7C trust chain MUST include a 448 single end-entity certificate and its trust authorities. No other 449 certificates are to be part of this chain. The number of P7C trust 450 chains in a CEM Request message MUST be equal to the number of end- 451 entity certificates being communicated in the CEM XML document. 452 If different end-entity certificates have common trust authorities' 453 certificates, each P7C cert chain still MUST include each certificate 454 necessary to create a trust anchor. Thus, if a recipient can not 455 create a trust relationship from the P7C cert chain, it MAY reject 456 the end-entity certificate in the CEM Request. 458 End-entity certificates are referenced and identified in the XML data 459 by their content-id used in the multipart/related structure. 460 Information on how the certificate is to be used, or certificate 461 usage, by the receiving user agent and other related information is 462 found in the XML data. A certificate can be used for a single 463 function, like digital signatures, or used for multiple functions, 464 such as both digital signatures and data encryption. If a certificate 465 is intended for multiple usages, such as for both digital signatures 466 and data encryption, the certificate MUST be listed only once in the 467 CEM Request message and its multiple usage listed through the 468 CertUsage XML element. 470 Upon receipt of the CEM Request, the recipient trading partner 471 processes the transport message as normal and returns the MDN. The 472 recipient MAY parse the CEM XML data prior to returning the MDN. If 473 the XML is not well-formed and can not be interpreted, the UA MAY 474 return the MDN with the error disposition modifier of "error: 475 unexpected-processing-error". The returned MDN does not provide 476 information on the acceptance of the certificate(s) being exchanged. 477 An UA who receives an MDN with an error disposition modifier MUST 478 consider the CEM Message was not understood and needs to be corrected 479 and retransmitted. 481 2.4 482 Certificate Implementation 484 The new certificate is considered to be in the Pending state for the 485 recipient who MUST decide whether to accept the certificate as 486 trustworthy. This decision is arbitrary and left to each individual 487 trading partner. Upon accepting the certificate, it is to be 488 considered an Accepted certificate within the trading partner 489 relationship. If the certificate is not accepted, it is considered 490 Rejected. 492 When a certificate is intended for use in data encryption, the 493 initiator MUST consider the certificate to be Accepted and be 494 prepared for its trading partner to begin using the certificate upon 495 generating the CEM Request message. After a recipient generates a 496 positive CEM Response message for a certificate, the recipient MUST 497 immediately begin using the certificate in trading with the initiator 498 of the request. The recipient MAY apply encryption to the CEM 499 Response message using the new Accepted certificate or MAY apply 500 encryption to the CEM Response message using the previously Accepted 501 encryption certificate. 503 When a certificate is intended for use in digital signatures or 504 TLS/SSL authentication, the initiator MUST NOT use the certificate 505 until the recipient trading partner generates a CEM Response 506 accepting the certificate or the respond by date, which is listed in 507 the RespondByDate XML element. The initiator MAY use the certificate 508 after the respond by date, regardless of whether the partner has 509 accepted it or not. The certificate used for the digital signature of 510 the CEM Request message MUST be the one which is currently Accepted 511 within the trading partner relationship. 513 Since implementers of EDIINT often use the same certificate with 514 multiple trading partners, implementers of CEM MUST be able to keep 515 both the old and new certificates as Accepted. If the initiator has 516 generated a CEM Request and exchanged a new encryption certificate to 517 multiple trading partners, it MUST be able to accept encrypted data 518 which uses either the older, existing encryption certificate or the 519 newly exchanged encryption certificate. Likewise, a recipient of a 520 CEM Request MUST be able to authenticate digital signatures using 521 either the new or old certificates, since the initiator may not be 522 able to switch certificates until all trading partners accept the new 523 certificate. Similar provisions MUST be made for certificates 524 intended for TLS/SSL server and client authentication. Revoking a 525 certificate MUST be done outside of CEM. 527 If a CEM Request message contains a certificate which is currently 528 Accepted and has the identical usage for the certificate that has 529 been Accepted, the recipient MUST NOT reject the duplicate 530 certificate but MUST respond with a CEM Response message indicating 531 the certificate has been accepted. For example, if Certificate A is 532 currently Accepted as the encryption certificate for a user agent, 534 any CEM Request message containing Certificate A with the usage as 535 encryption only MUST be accepted by an existing trading partner. This 536 situation may be necessary for an implementation intending to verify 537 its current trading partner certificate. 539 If two trading partners utilize multiple EDIINT protocols for 540 trading, such as AS2 for a primary transport and AS1 as the backup 541 transport, it is dependent upon implementation and trading partner 542 agreement how CEM messages are sent and which transports the 543 exchanged certificates affect. 545 2.5 546 CEM Response 548 The CEM Response message is a multipart/related envelope which 549 contains the CEM XML under the MIME type of application/ediint-cert- 550 exchange+xml. If a requestId is used in a CEM Request, then the 551 requestId MUST be present in the CEM Response with the same value. 552 The requestId allows for the CEM Response to be matched to the CEM 553 Request. If the CEM Request contains multiple TrustRequest elements 554 and the corresponding TrustResponse elements are returned in multiple 555 CEM Response messages, each CEM Response message MUST use the same 556 requestId from the originating CEM Request message. This is critical 557 when multiple CEM Requests are sent with the same certificate and the 558 CEM Response can not be matched solely through the TrustResponse 559 elements. 561 A TrustResponse XML element provides information needed to match the 562 end-entity certificate sent in an earlier CEM Request and indicate if 563 the certificate was accepted or rejected by the recipient. The 564 CertificateReference in a TrustResponse matches the 565 CertificateIdentifier value for the end-entity certificate in the CEM 566 Request. CertStatus indicates if the certificate was accepted or 567 rejected. If a CEM Request is received, the recipient MUST respond 568 with a CEM Response message indicating if the certificate is Accepted 569 or Rejected. More information about the XML attributes and value for 570 CEM Response can be found in 3.2. 572 If the certificate in the CEM Request message contains multiple 573 usages, such as for both digital signature and data encryption, only 574 a single TrustResponse is needed for that certificate. The CertStatus 575 value in the TrustResponse is the response for both usages of the 576 certificate. A recipient MUST NOT choose to accept the certificate 577 for one specified use and not the other. 579 If multiple end-entity certificates were included within the CEM 580 Request, the recipient MAY generate individual CEM Response messages 581 for each certificate or the recipient MAY consolidate the 582 TrustResponse for multiple certificates into one CEM Response 583 message. A CEM Response may contain multiple TrustResponse elements 584 for different certificates but MUST NOT contain two or more 585 TrustResponses for the same certificate. 587 If a second TrustResponse is received in a different message matching 588 the same certificate as that of an earlier TrustRespnse but the 589 CertStatus has a different value than the other, the originator MAY 590 accept the CertStatus value in the most recent TrustResponse but MAY 591 choose to ignore it. If the CertStatus in both TrustResponses are the 592 same, the originator should disregard the second TrustResponse. 594 If the originator receives a CEM Response message which violates the 595 rules listed above or is invalid in any way, the originator MAY 596 reject the message entirely but MUST return an MDN if requested. 598 3. 599 CEM XML Schema Description 601 The CEM schema has two top-level elements, 602 EDIINTCertificateExchangeRequest and 603 EDIINTCertificateExchangeResponse. The 604 EDIINTCertificateExchangeRequest element is present only in the CEM 605 Request message, and the EDIINTCertificateExchangeResponse is present 606 only in the CEM Response message. All other elements nest directly or 607 indirectly from these. CEM XML data must be well-formed and valid 608 relative to the CEM XML Schema. Please refer to the appendix for the 609 actual schema document. 611 3.1 612 EDIINTCertificateExchangeRequest element 614 EDIINTCertificateExchangeRequest contains element TradingPartnerInfo, 615 which can only appear once, and TrustRequest, which may be present 616 multiple times. TrustRequest contains information on a certificate 617 and its intended usage. TradingPartnerInfo exists to provide 618 information on the publication of the CEM Request message since 619 processing of the XML data may occur apart from the handling of the 620 accompanying transport message, for example the AS2 request. 622 623 624 625 626 629 631 632 634 635 636 638 EDIINTCertificateExchangeRequest also contains the attribute 639 requestId. RequestId uniquely identifies each CEM Request message. 641 Its value MUST be between 1 and 255 characters. The requestId is 642 returned in the CEM Response message to assist the UA in matching the 643 CEM Response with the CEM Request. 645 646 647 648 649 650 652 An optional Extension element is also present along with the 653 anyAttribute attribute. They exist to provide future extendibility 654 for new features which may be developed but not yet defined within 655 CEM. They are present in several locations in the schema for this 656 future extendibility. 658 659 660 661 663 664 665 667 TradingPartnerInfo identifies the entity that created the CEM message 668 through the nested Name element. Both the qualifier attribute and the 669 element value of Name follow mandatory naming conventions. The 670 qualifier attribute is to be the transport standard utilized. For 671 example, "AS1", "AS2" or "AS3". The value of the Name element is the 672 same value in the From header utilized by the transport. For AS2 and 673 AS3, this is the value in the AS2-From and AS3-From headers, 674 respectively. For AS1, this is the value of the From header. If other 675 transports besides AS1, AS2, AS3 are used, the same naming convention 676 SHOULD be followed. 678 MessageOriginated is included in TradingPartnerInfo to identify the 679 time and date the message was created. The MessageOriginated date and 680 time values MUST follow XML standard dateTime type syntax and be 681 listed to at least the nearest second and expressed in local time 682 with UTC offset. For example, a message originating from the US 683 Eastern Standard timezone would use 2005-03-01T14:05:00-05:00. 685 686 687 688 689 690 691 692 694 695 696 697 698 699 701 702 703 704 706 The TrustRequest element contains the EndEntity, CertUsage, 707 RespondByDate and ResponseURL elements. The required EndEntity 708 element is found only once in a TrustRequest element and contains the 709 content-id reference to the end-entity certificate being exchanged. 711 712 713 714 715 716 717 719 720 721 723 EndEntity contains the nested elements of CertificateIdentifier and 724 CertificateContentID. CertificateContentID is a string element which 725 references the content-id of the multipart/related structure where 726 the certificate is stored. CertificateIdentifier comes from the XML 727 Signature schema namespace [XML-DSIG]. 729 730 731 734 735 737 738 739 741 CertificateIdentifier contains the string element X509IssuerName and 742 the integer element X509SerialNumber. X509SerialNumber is the 743 assigned serial number of the end entity certificate as it is listed. 744 X509IssuerName contains the issuer name information of the end-entity 745 certificate, such as common name, organization, etc. This information 746 MUST be described in a string format per the rules of RFC 2253 747 [RFC2253]. This results in the attributes within the Issuer Name to 748 be listed with their attribute type followed by an "=" and the 749 attribute value. Each attribute type and value are separated by a "," 750 and any escape characters in the value are preceded by a "\". Refer 751 to the appendix and the sample CEM Request message for an example of 752 the X509IssuerName. 754 755 756 757 758 759 761 CertUsage is an unbounded element which contains enumerated values on 762 how the exchanged certificate is to be used. There are enumerated 763 values for SMIME digital signatures (digitalSignature), SMIME data 764 encryption (keyEncipherment), the server certificate used in TLS 765 transport encryption (tlsServer) and the client certificate used in 766 TLS transport encryption (tlsClient). While the element is unbounded, 767 CertUsage only has a potential number of four occurrences due to the 768 limit of the enumerated values. 770 771 772 773 774 775 776 777 778 780 RespondByDate is a required element of the XML standard dateTime type 781 expressed in local time with UTC offset, which provides information 782 on when the certificate should be trusted, inserted into the trading 783 partner relationship and responded to by a CEM Response message. If 784 the certificate can not be trusted or inserted into the trading 785 partner relationship, the CEM Response message should still be 786 returned by the date indicated. 788 790 ResponseURL is an element which indicates where the CEM Response 791 message should be sent. This value takes precedence over the existing 792 inbound URL of the current trading partner relationship. The Response 793 MUST use the same transport protocol (AS1, AS2, or AS3) as the 794 Request. 795 797 3.2 798 EDIINTCertificateExchangeResponse element 800 EDIINTCertificateExchangeResponse contains the two elements 801 TradingPartnerInfo and TrustResponse and the attribute requestId. 802 TradingPartnerInfo, which is also found in 803 EDIINTCertificateExchangeRequest, describes the trading partner 804 generating this response message. TrustResponse provides information 805 on the acceptance of a previously sent end entity certificate. There 806 can be multiple TrustResponse elements within an 807 EDIINTCertificateExchangeResponse. The requestId is the same value 808 from a previously sent CEM Request message. The requestId from the 809 CEM Response is matched up with the CEM Request. 811 812 813 814 815 818 820 821 823 824 825 827 828 829 830 831 833 835 836 837 839 A TrustResponse element identifies a certificate which has been 840 previously exchanged within the trading partner relationship through 841 a CEM Request and now has been either accepted or rejected by the 842 partner. The CertificateReference element is of the same type as the 843 CertificateIdentifier element. A CertificateReference element in a 844 CEM Response MUST be identical to its CertificateIdentifier 845 counterpart in the associated CEM Request since they identify the 846 same certificate in question. 848 The required element CertStatus has the enumerated values of 849 "Accepted" or "Rejected". "Accepted" indicates the certificate was 850 trusted by the trading partner and is now ready for use within the 851 trading partner relationship, and "Rejected" indicates the 852 certificate is not trusted by the trading partner nor can it be 853 currently used with the trading partner relationship. If the value of 854 "Rejected" is chosen, the optional string element ReasonForRejection 855 may be included. If present, ReasonForRejection should contain a 856 brief description of why the certificate was not accepted. Since the 857 value for this element is not enumerated but open, it MUST be 858 interpreted through human means. 860 861 862 863 864 865 866 867 869 4. 870 Use Case Scenario 872 This scenario illustrates how the CEM Request and CEM Response 873 messages described in Section 2 and 3 can be used to exchange 874 certificates. The scenario is only illustrative and any differences 875 between it and the rules above should defer to the rules in Section 2 876 and 3. 878 Two trading partners, Alpha Arrows and Bravo Bows, have an 879 established trading partner relationship using AS2. Alpha Arrows is 880 using a single certificate, CertA, for both digital signatures and 881 data encryption. Alpha Arrows wants to issue a new certificate, 882 CertB, for digital signatures but keep CertA for data encryption. 884 Bravo Bows is using one certificate, Cert1, for digital signatures 885 and another certificate, Cert2, for data encryption. Bravo Bows wants 886 to introduce a new certificate, Cert3, for digital signature and a 887 new certificate, Cert4, for data encryption. 889 1. Alpha Arrows sends a CEM Request to Bravo Bows containing only 890 CertB. The CertUsage has a value of "digitalSignature". Bravo Bows 891 immediately returns the MDN but must make an internal security 892 decision before accepting CertB. 894 2. While waiting for a CEM Response, Alpha Arrows continues to send 895 AS2 messages to Bravo Bows which have been signed using CertA. The 896 messages originating from Bravo Bows are encrypted using CertA. 898 3. Eventually, Bravo Bows returns a CEM Response with the CertStatus 899 of "Accepted" for CertB. Upon receipt, an MDN is returned which is 900 signed using CertA. Bravo Bows MUST be able to accept the MDN if it 901 has a digital signature from either CertA or CertB as Alpha Arrows 902 may not be able to switch certificates simply upon receipt of the CEM 903 Response message without parsing the XML payload. Also, Alpha Arrows 904 may need to wait for CEM Responses from other trading partners before 905 switching to the new CertB. However, as soon as possible, Alpha 906 Arrows should use CertB exclusively for digital signatures. 908 4. Bravo Bows sends a CEM Request to Alpha Arrows containing both 909 Cert3 and Cert4. The CertUsage for Cert3 and Cert4 are 910 "digitalSignature" and "keyEncipherment", respectively. Alpha Arrows 911 returns an MDN immediately. Bravo Bows is now prepared to receive any 912 inbound messages encrypted by either Cert2 or Cert4, but all its 913 digital signatures are still done through Cert1. 915 5. Eventually, Alpha Arrows returns a single CEM Response message. It 916 contains two TrustResponse elements: one for Cert3 and another for 917 Cert4. The CertStatus for Cert3 is "Rejected" with the 918 ReasonForRejection field present and populated with the string 919 "KeyUsage value was incorrect". CertStatus for Cert4 was "Accepted." 920 Bravo Bows returns the MDN signed through Cert1. 922 6. Immediately after this, an AS2 message is received from Alpha 923 Arrows which is encrypted using Cert4, and Bravo Bows is able to 924 decrypt the message successfully. Because Alpha Arrows rejected 925 Cert3, Bravo Bows is only using Cert1 for digital signatures and 926 returns the MDN signed with Cert1. 928 7. After creating a new certificate, Cert5, which corrects the 929 previous keyUsage problem, Bravo Bows sends Cert5 in a CEM Request. 931 8. Shortly after this, Alpha Arrows sends a CEM Response message for 932 Cert5. It contains a CertStatus of "Accepted". This CEM Response 933 message was encrypted using Cert4, but Bravo Bows was prepared for 934 encryption from either Cert2 or Cert4. The message is processed and a 935 good MDN is returned signed with Cert1. While, Bravo Bows can now 936 sign messages to Alpha Arrows with either Cert1 or Cert5, Bravo Bows 937 should use Cert5 exclusively as soon as possible. 939 5. 940 Profile Exchange Messaging 942 CEM provides the means to exchange certificates among trading 943 partners. However, other profile information, such as URLs and 944 preferred security settings, is needed to create a trading partner 945 relationship. A future standard is needed to describe profile 946 descriptions and how they will be exchanged. The format for this 947 profile attachment is not defined in this specification but is 948 planned for a future document. It will build upon the existing CEM 949 protocol with profile information stored with XML data. Both 950 certificate and profile description information will be placed into a 951 multipart/related [RFC2387] body part entity. A possible format for a 952 profile description message is as follows: 954 Various EDIINT headers 955 EDIINT-Features: profile-exchange 956 Disposition-Notification-To: http://10.1.1.1:80/exchange/as2_company 957 Disposition-Notification-Options: signed-receipt-protocol=optional, 958 pkcs7-signature; signed-receipt-micalg=optional, sha1 959 Content-Type: multipart/signed; micalg=sha1; 960 protocol="application/pkcs7-signature"; boundary="--BOUNDARY1" 962 ----BOUNDARY1 963 Content-Type: multipart/related; 964 start=""; 965 type="application/ediint-cert-exchange+xml"; 966 boundary="--BOUNDARY2" 968 ----BOUNDARY2 969 Content-Type: application/ediint-cert-exchange+xml 970 Content-ID: 972 [CEM XML data] 973 ----BOUNDARY2 974 [Profile information attachment] 975 ----BOUNDARY2-- 976 ----BOUNDARY1 978 Content-Type: application/pkcs7-signature 980 [Digital Signature] 981 ----BOUNDARY1-- 983 6. 984 Implementation Considerations 986 This section contains various points to explain practical 987 implementation considerations. 989 * If the EDIINT transport message carrying a CEM Request or CEM 990 Response fails resulting in a negative MDN, the CEM message, its 991 contents and instructions are to be ignored. The User Agent receiving 992 the negative MDN is to consider the CEM message to be ignored and 993 retransmit as needed. 995 * While a single end-entity certificate can be only be used once in a 996 single CEM Request message, the same certificate can be sent multiple 997 times in multiple CEM Request messages. The requestId is used for 998 matching the CEM Request and CEM Response messages. 1000 * Certificate usage is cumulative. Thus, if a User Agent receives a 1001 valid CEM Request message with Certificate A with certUsage set to 1002 digitalSignature and then a second valid CEM Request message with 1003 Certificate A with certUsage set to keyEncipherment, then the User 1004 Agent MUST configure the certificate to be used both for 1005 digitalSignature and keyEncipherment. As well, if at a later time a 1006 valid CEM Request message is received with Certificate A with 1007 certUsage set only to digitalSignature, Certificate A is still valid 1008 for keyEncipherment. 1010 7. 1011 Future Considerations for CEM I-D 1012 This section contains ideas for consideration in future versions of 1013 CEM and addressed in the future. If deemed necessary, they will be 1014 added into the I-D else they will be removed. This section will be 1015 removed prior to RFC submission. 1017 8. 1018 Security Considerations 1020 Certificate exchange is safe for transmitting. However, implementers 1021 SHOULD verify the received certificate to determine if it is truly 1022 from the stated originator through out-of-band means or whenever the 1023 request is not signed. 1025 9. 1026 IANA Considerations 1028 MIME Media type name: Application 1030 MIME subtype name: EDIINT-cert-exchange+xml 1032 Required parameters: None 1034 Optional parameters: This parameter has identical semantics to the 1035 charset parameter of the "application/xml" media type as specified 1036 in [RFC3023]. 1038 Encoding considerations: Identical to those of "application/xml" as 1039 described in [RFC3023], section 3.2. 1041 Security considerations: See section 6. 1043 Interoperability Considerations: See section 2.2 1045 Published specification: This document. 1047 Applications which use this media type: EDIINT applications, such as 1048 AS1, AS2 and AS3 implementations. 1050 Additional Information: None 1052 Intended Usage: Common 1054 Author/Change controller: See Author's section of this document. 1056 10. 1057 References 1058 10.1 1059 Normative References 1061 [AS1] RFC3335 "MIME-based Secure Peer-to-Peer Business Data 1062 Interchange over the Internet using SMTP", T. Harding, R. 1063 Drummond, C. Shih, 2002. 1065 [AS2] RFC4130 "MIME-based Secure Peer-to-Peer Business Data 1066 Interchange over the Internet using HTTP", D. Moberg, R. 1067 Drummond, 2005. 1069 [AS3] draft-ietf-ediint-as3-05.txt "MIME-based Secure Peer-to-Peer 1070 Business Data Interchange over the Internet using FTP", T. 1071 Harding, R. Scott, 2003. 1073 [EDIINT FEATURE] Meadors, K., "Electronic Data Interchange - Internet 1074 Integration (EDIINT) Features Header Field", RFC 6017, September 2010. 1076 [RFC2119] RFC2119 "Key Words for Use in RFC's to Indicate Requirement 1077 Levels", S.Bradner, March 1997. 1079 [RFC2246] RFC2246 "The TLS Protocol", Dierks, T. and C. Allen, 1080 October 1999. 1082 [RFC2253] RFC2253 "Lightweight Directory Access Protocol (v3): UTF-8 1083 String Representation of Distinguished Names", M. Wahl, S. Kille 1084 and T. Howes, Decemeber 1997. 1086 [RFC2387] RFC2387 "The MIME Multipart/Related Content-type", E. 1087 Levinson, August 1998. 1089 [RFC2828] RFC2828 "Internet Security Glossary", R. Shirley, May 2000. 1091 [RFC3023] RFC3023 "XML Media Types", M. Murata, October 2001. 1093 [XML-DSIG] RFC3275 "XML-Signature Syntax and Processing", D. 1094 Eastlake, March 2002. 1096 [X.520] ITU-T Recommendation X.520: Information Technology - Open 1097 Systems Interconnection - The Directory: Selected Attribute 1098 Types, 1993. 1100 [PROFILE] Housley, R., Polk, W., Ford, W. and D. Solo, "Internet 1101 X.509 Public Key Infrastructure: Certificate and CRL Profile", 1102 RFC 3280, April 2002. 1104 10.2 1105 Informative References 1107 11. 1108 Acknowledgments 1110 The authors wish to extend gratitude to the ecGIF sub-committee 1111 within the GS1 organization from which this effort began. Many have 1112 contributed to the development of this specification, but some 1113 deserve special recognition. John Duker who chaired the sub-committee 1114 and provided valuable editing. John Koehring with his work on the 1115 reference ID and shared important insights on implementation. Aaron 1116 Gomez in the coordinating of vendors testing CEM. Richard Bigelow who 1117 greatly assisted development of the ideas presented, and Debra Petta 1118 for her review and comments. 1120 Author's Addresses 1122 Kyle Meadors 1123 Drummond Group Inc. 1124 4700 Bryant Irvin Court, Suite 303 1125 Fort Worth, TX 76107 USA 1126 Email: kyle@drummondgroup.com 1128 Dale Moberg 1129 Axway, Inc. 1130 8388 E. Hartford Drive, Suite 100 1131 Scottsdale, AZ 85255 USA 1132 Email: dmoberg@us.axway.com 1134 Appendix 1136 A.1 EDIINT Certificate Exchange XML Schema 1138 1139 1145 1147 1148 1149 1150 1151 1153 1155 1156 1158 1159 1160 1161 1162 1163 1164 1165 1167 1169 1170 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1184 1185 1186 1187 1188 1189 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1224 1225 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1238 1239 1240 1241 1242 1243 1244 1245 1247 1249 1250 1251 1252 1253 1254 1255 1257 1258 1259 1260 1262 A.2 Example of EDIINT Certificate Exchange Request XML 1264 1265 1270 1271 DGI_Test_CEM 1272 1273 2005-08-30T00:30:00-05:00 1274 1275 1276 keyEncipherment 1277 digitalSignature 1278 2005-09-30T12:00:00-05:00 1279 http://10.1.1.1/as2 1280 1281 1282 CN=Cleo- 1283 SP,E=as2selfpacedsupport@drummondgroup.com,O=DGI,OU=DGI,L=Ft. 1284 Worth,S=Texas,C=US 1285 9659684611094873474886 1286 1287 1288 SignEncCert-Example_vs02@example.org 1289 1290 1291 1292 tlsServer 1293 2005-09-30T12:00:00-05:00 1294 http://10.1.1.1/as2 1295 1296 1297 CN=VeriSign Class 1 CA Individual 1298 Subscriber-Persona Not Validated,OU=www.verisign.com/repository/RPA 1299 Incorp. By Ref.\,LIAB.LTD(c)98,OU=VeriSign Trust Network,O=VeriSign\, 1300 Inc. 1301 2673611014597817669550861744279966682 1303 1304 1305 SSLCert-Example_vs02@example.org 1306 1307 1308 1310 A.3 Example of EDIINT Certificate Exchange Response XML 1312 1313 1318 1319 DGI_Test_CEM_Trading_Partner 1320 1321 2005-08-31T00:21:00-05:00 1322 1323 1324 Accepted 1325 1326 CN=Cleo- 1327 SP,E=as2selfpacedsupport@drummondgroup.com,O=DGI,OU=DGI,L=Ft. 1328 Worth,S=Texas,C=US 1329 9659684611094873474886 1330 1331 1332 1333 Accepted 1334 1335 CN=VeriSign Class 1 CA Individual 1336 Subscriber-Persona Not Validated,OU=www.verisign.com/repository/RPA 1337 Incorp. By Ref.\,LIAB.LTD(c)98,OU=VeriSign Trust Network,O=VeriSign\, 1338 Inc. 1339 2673611014597817669550861744279966682 1341 1342 1343 1345 Changes from Previous Versions 1347 B.1 Updates from Version 00 1349 . Updated security requirements in section 2.1, specifically in 1350 regards to digital signatures. 1351 . The XML element responseURL is now required. Modified section 1352 3.1 and example messages in appendix accordingly. 1353 . Certificates are exchanged within a full P7C cert chain. Section 1354 2.3 reflects this. 1355 . The XML element TrustChain is not longer necessary since the 1356 entire cert chain is stored. Removed references in schema and 1357 document. 1358 . Added statement in 2.5 that multiple CEM Responses SHOULD NOT be 1359 sent and that if this occurs, the action of the CEM Request 1360 initiator is not defined. 1361 . Updated the examples in Appendix B to reflect the current usage. 1363 B.2 Updates from Version 01 1365 . Added information for handling different scenarios with CEM 1366 Response message. 1367 . Rewrote use case scenarios. 1368 . Added the EDIINT Features header information. 1370 B.3 Updates from Version 02 1371 . Modified use of SSL certificates to match real-world needs. 1372 . Modified schema in changing namespace value and removed schema 1373 location. 1374 . Added statement that CEM XML must be well-formed and valid to 1375 schema. 1376 . Modified Use Case to correct an error and improve clarity. 1377 . Added section 1.4 to describe CEM process. 1379 B.4 Updates from Version 03 1380 . None. Update done because vs03 expired. 1382 B.5 Updates from Version 04 1383 . Clarified requirement of using multipart/related for CEM 1384 Response. 1385 . Added sections on Implementation Considerations and Future 1386 Implementation. 1387 . Modified schema to allow future extensions. 1388 . Changed requirements on qualifier attribute in the Name 1389 element. 1390 . Changed functionality to allow error MDN to be returned when 1391 CEM XML can not be parsed. 1393 B.6 Updates from Version 05 1394 . Added requestId to CEM. 1395 . Removed normative reference to RFC 3821. 1397 B.7 Updates from Version 06/07/08/09/10/11 1398 . None. Updated for 6-month I-D expiration.