Network Working Group                                          D. Moberg
Request for Comments: 4130                              Cyclone Commerce
Category: Standards Track                                    R. Drummond
                                                    Drummond Group Inc.
                                                              July 2005


                    MIME-Based Secure Peer-to-Peer
                Business Data Interchange Using HTTP,
                   Applicability Statement 2 (AS2)

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

  Copyright (C) The Internet Society (2005).

Abstract

  This document provides an applicability statement (RFC 2026, Section
  3.2) that describes how to exchange structured business data securely
  using the HTTP transfer protocol, instead of SMTP; the applicability
  statement for SMTP is found in RFC 3335.  Structured business data
  may be XML; Electronic Data Interchange (EDI) in either the American
  National Standards Committee (ANSI) X12 format or the UN Electronic
  Data Interchange for Administration, Commerce, and Transport
  (UN/EDIFACT) format; or other structured data formats.  The data is
  packaged using standard MIME structures.  Authentication and data
  confidentiality are obtained by using Cryptographic Message Syntax
  with S/MIME security body parts.  Authenticated acknowledgements make
  use of multipart/signed Message Disposition Notification (MDN)
  responses to the original HTTP message.  This applicability statement
  is informally referred to as "AS2" because it is the second
  applicability statement, produced after "AS1", RFC 3335.











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Table of Contents

  1. Introduction ....................................................3
     1.1. Applicable RFCs ............................................3
     1.2. Terms ......................................................3
  2. Overview ........................................................5
     2.1. Overall Operation ..........................................5
     2.2. Purpose of a Security Guideline for MIME EDI ...............5
     2.3. Definitions ................................................5
     2.4. Assumptions ................................................7
  3. Referenced RFCs and Their Contributions .........................9
     3.1. RFC 2616 HTTP v1.1 [3] .....................................9
     3.2. RFC 1847 MIME Security Multiparts [6] ......................9
     3.3. RFC 3462 Multipart/Report [8] .............................10
     3.4. RFC 1767 EDI Content [2] ..................................10
     3.5. RFC 2045, 2046, and 2049 MIME [1] .........................10
     3.6. RFC 3798 Message Disposition Notification [5] .............10
     3.7. RFC 3851 and 3852 S/MIME Version 3.1 Message
          Specifications and Cryptographic Message Syntax (CMS) [7]..10
     3.8. RFC 3023 XML Media Types [10] .............................10
  4. Structure of an AS2 Message ....................................10
     4.1. Introduction ..............................................10
     4.2. Structure of an Internet EDI MIME Message .................11
  5. HTTP Considerations ............................................12
     5.1. Sending EDI in HTTP POST Requests .........................12
     5.2. Unused MIME Headers and Operations ........................12
     5.3. Modification of MIME or Other Headers or Parameters Used ..13
     5.4. HTTP Response Status Codes ................................14
     5.5. HTTP Error Recovery .......................................14
  6. Additional AS2-Specific HTTP Headers ...........................14
     6.1. AS2 Version Header ........................................15
     6.2. AS2 System Identifiers ....................................15
  7. Structure and Processing of an MDN Message .....................17
     7.1. Introduction ..............................................17
     7.2. Synchronous and Asynchronous MDNs .........................19
     7.3. Requesting a Signed Receipt ...............................21
     7.4. MDN Format and Values .....................................25
     7.5. Disposition Mode, Type, and Modifier ......................30
     7.6. Receipt Reply Considerations in an HTTP POST ..............35
  8. Public Key Certificate Handling ................................35
  9. Security Considerations ........................................36
     9.1. NRR Cautions ..............................................37
     9.2. HTTPS Remark ..............................................38
     9.3. Replay Remark .............................................39
  10. IANA Considerations ...........................................39
      10.1. Registration ............................................39
  11. Acknowledgements ..............................................40
  12. References ....................................................40



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      12.1. Normative References ....................................40
      12.2. Informative References ..................................41
  Appendix A: Message Examples ......................................42

1.  Introduction

1.1.  Applicable RFCs

  Previous work on Internet EDI focused on specifying MIME content
  types for EDI data [2] and extending this work to support secure
  EC/EDI transport over SMTP [4].  This document expands on RFC 1767 to
  specify a comprehensive set of data security features, specifically
  data confidentiality, data integrity/authenticity, non-repudiation of
  origin, and non-repudiation of receipt over HTTP.  This document also
  recognizes contemporary RFCs and is attempting to "re-invent" as
  little as possible.  Although this document focuses on EDI data, any
  other data types describable in a MIME format are also supported.

  Internet MIME-based EDI can be accomplished by using and complying
  with the following RFCs:

    o  RFC 2616 Hyper Text Transfer Protocol
    o  RFC 1767 EDI Content Type
    o  RFC 3023 XML Media Types
    o  RFC 1847 Security Multiparts for MIME
    o  RFC 3462 Multipart/Report
    o  RFC 2045 to 2049 MIME RFCs
    o  RFC 3798 Message Disposition Notification
    o  RFC 3851, 3852 S/MIME v3.1 Specification

  Our intent here is to define clearly and precisely how these are used
  together, and what is required by user agents to be compliant with
  this document.

  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
  "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
  document are to be interpreted as described in RFC 2119 [13].

1.2.  Terms

  AS2:     Applicability Statement 2 (this document); see RFC 2026
           [11], Section 3.2

  EDI:     Electronic Data Interchange

  EC:      Business-to-Business Electronic Commerce

  B2B:     Business to Business



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  Receipt: The functional message that is sent from a receiver to a
           sender to acknowledge receipt of an EDI/EC interchange.
           This message may be either synchronous or asynchronous in
           nature.

  Signed Receipt: A receipt with a digital signature.

  Synchronous Receipt: A receipt returned to the sender during the same
           HTTP session as the sender's original message.

  Asynchronous Receipt: A receipt returned to the sender on a different
           communication session than the sender's original message
           session.

  Message Disposition Notification (MDN): The Internet messaging format
           used to convey a receipt.  This term is used interchangeably
           with receipt.  A MDN is a receipt.

  Non-repudiation of receipt (NRR): A "legal event" that occurs when
           the original sender of an signed EDI/EC interchange has
           verified the signed receipt coming back from the receiver.
           The receipt contains data identifying the original message
           for which it is a receipt, including the message-ID and a
           cryptographic hash (MIC).  The original sender must retain
           suitable records providing evidence concerning the message
           content, its message-ID, and its hash value.  The original
           sender verifies that the retained hash value is the same as
           the digest of the original message, as reported in the
           signed receipt.  NRR is not considered a technical message,
           but instead is thought of as an outcome of possessing
           relevant evidence.

  S/MIME:  A format and protocol for adding cryptographic signature
           and/or encryption services to Internet MIME messages.

  Cryptographic Message Syntax (CMS): An encapsulation syntax used to
           digitally sign, digest, authenticate, or encrypt arbitrary
           messages.

  SHA-1:   A secure, one-way hash algorithm used in conjunction with
           digital signature.  This is the recommended algorithm for
           AS2.

  MD5:     A secure, one-way hash algorithm used in conjunction with
           digital signature.  This algorithm is allowed in AS2.






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  MIC:     The message integrity check (MIC), also called the message
           digest, is the digest output of the hash algorithm used by
           the digital signature.  The digital signature is computed
           over the MIC.

  User Agent (UA): The application that handles and processes the AS2
           request.

2.  Overview

2.1.  Overall Operation

  A HTTP POST operation [3] is used to send appropriately packaged EDI,
  XML, or other business data.  The Request-URI ([3], Section 9.5)
  identifies a process for unpacking and handling the message data and
  for generating a reply for the client that contains a message
  disposition acknowledgement (MDN), either signed or unsigned.  The
  MDN is either returned in the HTTP response message body or by a new
  HTTP POST operation to a URL for the original sender.

  This request/reply transactional interchange can provide secure,
  reliable, and authenticated transport for EDI or other business data
  using HTTP as a transfer protocol.

  The security protocols and structures used also support auditable
  records of these document data transmissions, acknowledgements, and
  authentication.

2.2.  Purpose of a Security Guideline for MIME EDI

  The purpose of these specifications is to ensure interoperability
  between B2B EC user agents, invoking some or all of the commonly
  expected security features.  This document is also NOT limited to
  strict EDI use; it applies to any electronic commerce application for
  which business data needs to be exchanged over the Internet in a
  secure manner.

2.3.  Definitions

2.3.1.  The Secure Transmission Loop

  This document's focus is on the formats and protocols for exchanging
  EDI/EC content securely in the Internet's HTTP environment.

  In the "secure transmission loop" for EDI/EC, one organization sends
  a signed and encrypted EDI/EC interchange to another organization and





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  requests a signed receipt, and later the receiving organization sends
  this signed receipt back to the sending organization.  In other
  words, the following transpires:

     o  The organization sending EDI/EC data signs and encrypts the
        data using S/MIME.  In addition, the message will request that
        a signed receipt be returned to the sender.  To support NRR,
        the original sender retains records of the message, message-ID,
        and digest (MIC) value.

     o  The receiving organization decrypts the message and verifies
        the signature, resulting in verified integrity of the data and
        authenticity of the sender.

     o  The receiving organization then returns a signed receipt using
        the HTTP reply body or a separate HTTP POST operation to the
        sending organization in the form of a signed message
        disposition notification.  This signed receipt will contain the
        hash of the received message, allowing the original sender to
        have evidence that the received message was authenticated
        and/or decrypted properly by the receiver.

  The above describes functionality that, if implemented, will satisfy
  all security requirements and implement non-repudiation of receipt
  for the exchange.  This specification, however, leaves full
  flexibility for users to decide the degree to which they want to
  deploy those security features with their trading partners.

2.3.2.  Definition of Receipts

  The term used for both the functional activity and the message for
  acknowledging delivery of an EDI/EC interchange is "receipt" or
  "signed receipt".  The first term is used if the acknowledgment is
  for an interchange resulting in a receipt that is NOT signed.  The
  second term is used if the acknowledgement is for an interchange
  resulting in a receipt that IS signed.

  The term non-repudiation of receipt (NRR) is often used in
  combination with receipts.  NRR refers to a legal event that occurs
  only when the original sender of an interchange has verified the
  signed receipt coming back from recipient of the message, and has
  verified that the returned MIC value inside the MDN matches the
  previously recorded value for the original message.

  NRR is best established when both the original message and the
  receipt make use of digital signatures.  See the Security
  Considerations section for some cautions regarding NRR.




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  For information on how to format and process receipts in AS2, refer
  to Section 7.

2.4.  Assumptions

2.4.1.  EDI/EC Process Assumptions

  o  Encrypted object is an EDI/EC Interchange.

  This specification assumes that a typical EDI/EC interchange is the
  lowest-level object that will be subject to security services.

  Specifically, in EDI ANSI X12, this means that anything between and
  including, segments ISA and IEA is secured.  In EDIFACT, this means
  that anything between, and including, segments UNA/UNB and UNZ is
  secured.  In other words, the EDI/EC interchanges including envelope
  segments remain intact and unreadable during fully secured transport.

  o  EDI envelope headers are encrypted.

  Congruent with the above statement, EDI envelope headers are NOT
  visible in the MIME package.

  In order to optimize routing from existing commercial EDI networks
  (called Value Added Networks or VANs) to the Internet, it would be
  useful to make some envelope information visible.  This
  specification, however, provides no support for this optimization.

  o  X12.58 and UN/EDIFACT Security Considerations

  The most common EDI standards bodies, ANSI X12 and EDIFACT, have
  defined internal provisions for security.  X12.58 is the security
  mechanism for ANSI X12, and AUTACK provides security for EDIFACT.
  This specification does NOT dictate use or non-use of these security
  standards.  They are both fully compatible, though possibly
  redundant, with this specification.

2.4.2.  Flexibility Assumptions

  o  Encrypted or Unencrypted Data

  This specification allows for EDI/EC message exchange in which the
  EDI/EC data can be either unprotected or protected by means of
  encryption.







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  o  Signed or Unsigned Data

  This specification allows for EDI/EC message exchange with or without
  digital signature of the original EDI transmission.

  o  Optional Use of Receipt

  This specification allows for EDI/EC message transmission with or
  without a request for receipt notification.  A signed receipt
  notification is requested; however, a MIC value is REQUIRED as part
  of the returned receipt, except when a severe error condition
  prevents computation of the digest value.  In the exceptional case, a
  signed receipt should be returned with an error message that
  effectively explains why the MIC is absent.

  o  Use of Synchronous or Asynchronous Receipts

  In addition to a receipt request, this specification allows the
  specification of the type of receipt that should be returned.  It
  supports synchronous or asynchronous receipts in the MDN format
  specified in Section 7 of this document.

  o  Security Formatting

  This specification relies on the guidelines set forth in RFC
  3851/3852  [7] "S/MIME Version 3.1 Message Specification;
  Cryptographic Message Syntax".

  o  Hash Function, Message Digest Choices

  When a signature is used, it is RECOMMENDED that the SHA-1 hash
  algorithm be used for all outgoing messages, and that both MD5 and
  SHA-1 be supported for incoming messages.

  o  Permutation Summary

  In summary, the following twelve security permutations are possible
  in any given trading relationship:

  1.  Sender sends un-encrypted data and does NOT request a receipt.

  2.  Sender sends un-encrypted data and requests an unsigned receipt.
      Receiver sends back the unsigned receipt.

  3.  Sender sends un-encrypted data and requests a signed receipt.
      Receiver sends back the signed receipt.

  4.  Sender sends encrypted data and does NOT request a receipt.



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  5.  Sender sends encrypted data and requests an unsigned receipt.
      Receiver sends back the unsigned receipt.

  6.  Sender sends encrypted data and requests a signed receipt.
      Receiver sends back the signed receipt.

  7.  Sender sends signed data and does NOT request a signed or
      unsigned receipt.

  8.  Sender sends signed data and requests an unsigned receipt.
      Receiver sends back the unsigned receipt.

  9.  Sender sends signed data and requests a signed receipt.
      Receiver sends back the signed receipt.

  10. Sender sends encrypted and signed data and does NOT request a
      signed or unsigned receipt.

  11. Sender sends encrypted and signed data and requests an unsigned
      receipt.  Receiver sends back the unsigned receipt.

  12. Sender sends encrypted and signed data and requests a signed
      receipt.  Receiver sends back the signed receipt.

  Users can choose any of the twelve possibilities, but only the last
  example (12), when a signed receipt is requested, offers the whole
  suite of security features described in Section 2.3.1, "The Secure
  Transmission Loop".

  Additionally, the receipts discussed above may be either synchronous
  or asynchronous depending on the type requested.  The use of either
  the synchronous or asynchronous receipts does not change the nature
  of the secure transmission loop in support of NRR.

3.  Referenced RFCs and Their Contributions

3.1.  RFC 2616 HTTP v1.1 [3]

  This document specifies how data is transferred using HTTP.

3.2.  RFC 1847 MIME Security Multiparts [6]

  This document defines security multipart for MIME:
  multipart/encrypted and multipart/signed.







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3.3.  RFC 3462 Multipart/Report [8]

  This RFC defines the use of the multipart/report content type,
  something that the MDN RFC 3798 builds upon.

3.4.  RFC 1767 EDI Content [2]

  This RFC defines the use of content type "application" for ANSI X12
  (application/EDI-X12), EDIFACT (application/EDIFACT), and mutually
  defined EDI (application/EDI-Consent).

3.5.  RFC 2045, 2046, and 2049 MIME [1]

  These are the basic MIME standards, upon which all MIME related RFCs
  build, including this one.  Key contributions include definitions of
  "content type", "sub-type", and "multipart", as well as encoding
  guidelines, which establish 7-bit US-ASCII as the canonical character
  set to be used in Internet messaging.

3.6.  RFC 3798 Message Disposition Notification [5]

  This Internet RFC defines how an MDN is requested, and the format and
  syntax of the MDN.  The MDN is the basis upon which receipts and
  signed receipts are defined in this specification.

3.7.  RFC 3851 and 3852 S/MIME Version 3.1 Message Specifications and
     Cryptographic Message Syntax (CMS) [7]

  This specification describes how S/MIME will carry CMS Objects.

3.8.  RFC 3023 XML Media Types [10]

  This RFC defines the use of content type "application" for XML
  (application/xml).

4.  Structure of an AS2 Message

4.1.  Introduction

  The basic structure of an AS2 message consists of MIME format inside
  an HTTP message with a few additional specific AS2 headers.  The
  structures below are described hierarchically in terms of which RFCs
  are applied to form the specific structure.  For details of how to
  code in compliance with all RFCs involved, turn directly to the RFCs
  referenced.  Any difference between AS2 implantations and RFCs are
  mentioned specifically in the sections below.





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4.2.  Structure of an Internet EDI MIME Message

  No encryption, no signature
     -RFC2616/2045
        -RFC1767/RFC3023 (application/EDIxxxx or /xml)

  No encryption, signature
     -RFC2616/2045
       -RFC1847 (multipart/signed)
         -RFC1767/RFC3023 (application/EDIxxxx or /xml)
         -RFC3851 (application/pkcs7-signature)

  Encryption, no signature
     -RFC2616/2045
       -RFC3851 (application/pkcs7-mime)
         -RFC1767/RFC3023  (application/EDIxxxx or /xml)(encrypted)

  Encryption, signature
     -RFC2616/2045
       -RFC3851 (application/pkcs7-mime)
         -RFC1847 (multipart/signed)(encrypted)
           -RFC1767/RFC3023  (application/EDIxxxx or /xml)(encrypted)
           -RFC3851 (application/pkcs7-signature)(encrypted)

  MDN over HTTP, no signature
     -RFC2616/2045
       -RFC3798 (message/disposition-notification)

  MDN over HTTP, signature
     -RFC2616/2045
       -RFC1847 (multipart/signed)
        -RFC3798 (message/disposition-notification)
        -RFC3851 (application/pkcs7-signature)

  MDN over SMTP, no signature
  MDN over SMTP, signature
    Refer to the EDI over SMTP standard [4].

  Although all MIME content types SHOULD be supported, the following
  MIME content types MUST be supported:

            Content-type: multipart/signed
            Content-Type: multipart/report
            Content-type: message/disposition-notification
            Content-Type: application/PKCS7-signature
            Content-Type: application/PKCS7-mime
            Content-Type: application/EDI-X12




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            Content-Type: application/EDIFACT
            Content-Type: application/edi-consent
            Content-Type: application/XML

5.  HTTP Considerations

5.1.  Sending EDI in HTTP POST Requests

  The request line will have the form: "POST Request-URI HTTP/1.1",
  with spaces and followed by a CRLF.  The Request URI is typically
  exchanged out of band, as part of setting up a bilateral trading
  partner agreement.  Applications SHOULD be prepared to deal with an
  initial reply containing a status indicating a need for
  authentication of the usual types used for authorizing access to the
  Request-URI ([3], Section 10.4.2 and elsewhere).

  The request line is followed by entity headers specifying content
  length ([3], Section 14.14) and content type ([3], Section 14.18).
  The Host request header ([3], Sections 9 and 14.23) is also included.

  When using Transport Layer Security [15] or SSLv3, the request-URI
  SHOULD indicate the appropriate scheme value, HTTPS.  Usually only a
  multipart/signed message body would be sent using TLS, as encrypted
  message bodies would be redundant.  However, encrypted message bodies
  are not prohibited.

  The receiving AS2 system MAY disconnect from the sending AS2 system
  before completing the reception of the entire entity if it determines
  that the entity being sent is too large to process.

  For HTTP version 1.1, TCP persistent connections are the default,
  ([3] Sections 8.1.2, 8.2, and 19.7.1).  A number of other differences
  exist because HTTP does not conform to MIME [1] as used in SMTP
  transport.  Relevant differences are summarized below.

5.2.  Unused MIME Headers and Operations

5.2.1.  Content-Transfer-Encoding Not Used in HTTP Transport

  HTTP can handle binary data and so there is no need to use the
  content transfer encodings of MIME [1].  This difference is discussed
  in [3], Section 19.4.5.  However, a content transfer encoding value
  of binary or 8-bit is permissible but not required.  The absence of
  this header MUST NOT result in transaction failure.  Content transfer
  encoding of MIME bodyparts within the AS2 message body is also
  allowed.





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5.2.2.  Message Bodies

  In [3], Section 3.7.2, it is explicitly noted that multiparts MUST
  have null epilogues.

  In [4], Section 5.4.1, options for large file processing are
  discussed for SMTP transport.  For HTTP, large files SHOULD be
  handled correctly by the TCP layer.  However, in [3], Sections 3.5
  and 3.6 discuss some options for compressing or chunking entities to
  be transferred.  In [3], Section 8.1.2.2 discusses a pipelining
  option that is useful for segmenting large amounts of data.

5.3.  Modification of MIME or Other Headers or Parameters Used

5.3.1.  Content-Length

  The use of the content-length header MUST follow the guidelines of
  [3], specifically Sections 4.4 and 14.13.

5.3.2.  Final Recipient and Original Recipient

  The final and original recipient values SHOULD be the same value.
  These values MUST NOT be aliases or mailing lists.

5.3.3.  Message-Id and Original-Message-Id

  Message-Id and Original-Message-Id is formatted as defined in RFC
  2822 [9]:

         "<" id-left "@" id-right ">"        (RFC 2822, 3.6.4)

  Message-Id length is a maximum of 998 characters.  For maximum
  backward compatibility, Message-Id length SHOULD be 255 characters or
  less.  Message-Id SHOULD be globally unique, and id-right SHOULD be
  something unique to the sending host environment (e.g., a host name).

  When sending a message, always include the angle brackets.  Angle
  brackets are not part of the Message-Id value.  For maximum backward
  compatibility, when receiving a message, do not check for angle
  brackets.  When creating the Original-Message-Id header in an MDN,
  always use the exact syntax as received on the original message;
  don't strip or add angle brackets.









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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


5.3.4.  Host Header

  The host request header field MUST be included in the POST request
  made when sending business data.  This field is intended to allow one
  server IP address to service multiple hostnames, and potentially to
  conserve IP addresses.  See [3], Sections 14.23 and 19.5.1.

5.4.  HTTP Response Status Codes

  The status codes return status concerning HTTP operations.  For
  example, the status code 401, together with the WWW-Authenticate
  header, is used to challenge the client to repeat the request with an
  Authorization header.  Other explicit status codes are documented in
  [3], Section 6.1.1 and throughout Section 10.

  For errors in the request-URI, 400 ("Bad Request"), 404 ("Not
  Found"), and similar codes are appropriate status codes.  These codes
  and their semantics are specified by [3].  A careful examination of
  these codes and their semantics should be made before implementing
  any retry functionality.  Retries SHOULD NOT be made if the error is
  not transient or if retries are explicitly discouraged.

5.5.  HTTP Error Recovery

  If the HTTP client fails to read the HTTP server response data, the
  POST operation with identical content, including same Message-ID,
  SHOULD be repeated, if the condition is transient.

  The Message-ID on a POST operation can be reused if and only if all
  of the content (including the original Date) is identical.

  Details of the retry process (including time intervals to pause,
  number of retries to attempt, and timeouts for retrying) are
  implementation dependent.  These settings are selected as part of the
  trading partner agreement.

  Servers SHOULD be prepared to receive a POST with a repeated
  Message-ID.  The MIME reply body previously sent SHOULD be resent,
  including the MDN and other MIME parts.

6.  Additional AS2-Specific HTTP Headers

  The following headers are to be included in all AS2 messages and all
  AS2 MDNs, except for asynchronous MDNs that are sent using SMTP and
  that follow the AS1 semantics[4].






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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


6.1.  AS2 Version Header

  To promote backward compatibility, AS2 includes a version header:

  AS2-Version: 1.0  - Used in all implementations of this
                      specification.  1.x will be interpreted as 1.0 by
                      all implementations with the "AS2 Version: 1.0"
                      header.  That is, only the most significant digit
                      is used as the version identifier for those not
                      implementing additional non-AS2-specified
                      functionality. "AS2-Version: 1.0 through 1.9" MAY
                      be used.  All implementations MUST interpret "1.0
                      through 1.9" as implementing this specification.
                      However, an implementation MAY extend this
                      specification with additional functionality by
                      specifying versions 1.1 through 1.9.  If this
                      mechanism is used, the additional functionality
                      MUST be completely transparent to implementations
                      with the "AS2-Version:  1.0" designation.

  AS2-Version: 1.1  - Designates those implementations that support
                      compression as defined by RFC 3274.

  Receiving systems MUST NOT fail due to the absence of the AS2-Version
  header.  Its absence would indicate that the message is from an
  implementation based on a previous version of this specification.

6.2.  AS2 System Identifiers

  To aid the receiving system in identifying the sending system,
  AS2-From and AS2-To headers are used.

         AS2-From: < AS2-name >
         AS2-To: < AS2-name >

  These AS2 headers contain textual values, as described below,
  identifying the sender/receiver of a data exchange.  Their values may
  be company specific, such as Data Universal Numbering System (DUNS)
  numbers, or they may be simply identification strings agreed upon
  between the trading partners.











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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


     AS2-text = "!" /           ; printable ASCII characters
                %d35-91 /       ; except double-quote (%d34)
                %d93-126        ; or backslash (%d92)

     AS2-qtext = AS2-text / SP  ; allow space only in quoted text

     AS2-quoted-pair = "\" DQUOTE /  ; \" or
                       "\" "\"       ; \\

     AS2-quoted-name = DQUOTE 1*128( AS2-qtext /
                                     AS2-quoted-pair) DQUOTE

     AS2-atomic-name = 1*128AS2-text

     AS2-name = AS2-atomic-name / AS2-quoted-name

  The AS2-From header value and the AS2-To header value MUST each be an
  AS2-name, MUST each be comprised of from 1 to 128 printable ASCII
  characters, and MUST NOT be folded.  The value in each of these
  headers is case-sensitive.  The string definitions given above are in
  ABNF format [14].

  The AS2-quoted-name SHOULD be used only if the AS2-name does not
  conform to AS2-atomic-name.

  The AS2-To and AS2-From header fields MUST be present in all AS2
  messages and AS2 MDNs whether asynchronous or synchronous in nature,
  except for asynchronous MDNs, which are sent using SMTP.

  The AS2-name for the AS2-To header in a response or MDN MUST match
  the AS2-name of the AS2-From header in the corresponding request
  message.  Likewise, the AS2-name for the AS2-From header in a
  response or MDN MUST match the AS2-name of the AS2-To header in the
  corresponding AS2 request message.

  The sending system may choose to limit the possible AS2-To/AS2-From
  textual values but MUST not exceed them.  The receiving system MUST
  make no restrictions on the textual values and SHOULD handle all
  possible implementations.  However, implementers must be aware that
  older AS2 products may not adhere to this convention.  Trading
  partner agreements should be made to ensure that older products can
  support the system identifiers that are used.

  There is no required response to a client request containing invalid
  or unknown AS2-From or AS2-To header values.  The receiving AS2
  system MAY return an unsigned MDN with an explanation of the error,
  if the sending system requested an MDN.




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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


7.  Structure and Processing of an MDN Message

7.1.  Introduction

  In order to support non-repudiation of receipt, a signed receipt,
  based on digitally signing a message disposition notification, is to
  be implemented by a receiving trading partner's UA.  The message
  disposition notification, specified by RFC 3798, is digitally signed
  by a receiving trading partner as part of a multipart/signed MIME
  message.

  The following support for signed receipts is REQUIRED:

     1. The ability to create a multipart/report; where the
        report-type = disposition-notification.

     2. The ability to calculate a message integrity check (MIC) on the
        received message.  The calculated MIC value will be returned to
        the sender of the message inside the signed receipt.

     3. The ability to create a multipart/signed content with the
        message disposition notification as the first body part, and
        the signature as the second body part.

     4. The ability to return the signed receipt to the sending trading
        partner.

     5. The ability to return either a synchronous or an asynchronous
        receipt as the sending party requests.

  The signed receipt is used to notify a sending trading partner that
  requested the signed receipt that:

     1. The receiving trading partner acknowledges receipt of the sent
        EC Interchange.

     2. If the sent message was signed, then the receiving trading
        partner has authenticated the sender of the EC Interchange.

     3. If the sent message was signed, then the receiving trading
        partner has verified the integrity of the sent EC Interchange.










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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  Regardless of whether the EDI/EC Interchange was sent in S/MIME
  format, the receiving trading partner's UA MUST provide the following
  basic processing:

     1. If the sent EDI/EC Interchange is encrypted, then the encrypted
        symmetric key and initialization vector (if applicable) is
        decrypted using the receiver's private key.

     2. The decrypted symmetric encryption key is then used to decrypt
        the EDI/EC Interchange.

     3. The receiving trading partner authenticates signatures in a
        message using the sender's public key.  The authentication
        algorithm performs the following:

        a. The message integrity check (MIC or Message Digest), is
           decrypted using the sender's public key.

        b. A MIC on the signed contents (the MIME header and encoded
           EDI object, as per RFC 1767) in the message received is
           calculated using the same one-way hash function that the
           sending trading partner used.

        c. The MIC extracted from the message that was sent and the MIC
           calculated using the same one-way hash function that the
           sending trading partner used are compared for equality.

     4. The receiving trading partner formats the MDN and sets the
        calculated MIC into the "Received-content-MIC" extension field.

     5. The receiving trading partner creates a multipart/signed MIME
        message according to RFC 1847.

     6. The MDN is the first part of the multipart/signed message, and
        the digital signature is created over this MDN, including its
        MIME headers.

     7. The second part of the multipart/signed message contains the
        digital signature.  The "protocol" option specified in the
        second part of the multipart/signed is as follows:

              S/MIME: protocol = "application/pkcs-7-signature"

     8. The signature information is formatted according to S/MIME
        specifications.






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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  The EC Interchange and the RFC 1767 MIME EDI content header can
  actually be part of a multi-part MIME content-type.  When the EDI
  Interchange is part of a multi-part MIME content-type, the MIC MUST
  be calculated across the entire multi-part content, including the
  MIME headers.

  The signed MDN, when received by the sender of the EDI Interchange,
  can be used by the sender as follows:

       o  As an acknowledgement that the EDI Interchange sent was
          delivered and acknowledged by the receiving trading partner.
          The receiver does this by returning the original-message-id
          of the sent message in the MDN portion of the signed receipt.

       o  As an acknowledgement that the integrity of the EDI
          Interchange was verified by the receiving trading partner.
          The receiver does this by returning the calculated MIC of the
          received EC Interchange (and 1767 MIME headers) in the
          "Received-content-MIC" field of the signed MDN.

       o  As an acknowledgement that the receiving trading partner has
          authenticated the sender of the EDI Interchange.

       o  As a non-repudiation of receipt when the signed MDN is
          successfully verified by the sender with the receiving
          trading partner's public key and the returned MIC value
          inside the MDN is the same as the digest of the original
          message.

7.2.  Synchronous and Asynchronous MDNs

  The AS2-MDN exists in two varieties: synchronous and asynchronous.

  The synchronous AS2-MDN is sent as an HTTP response to an HTTP POST
  or as an HTTPS response to an HTTPS POST.  This form of AS2-MDN is
  called synchronous because the AS2-MDN is returned to the originator
  of the POST on the same TCP/IP connection.

  The asynchronous AS2-MDN is sent on a separate HTTP, HTTPS, or SMTP
  TCP/IP connection.  Logically, the asynchronous AS2-MDN is a response
  to an AS2 message.  However, at the transfer-protocol layer, assuming
  that no HTTP pipelining is utilized, the asynchronous AS2-MDN is
  delivered on a unique TCP/IP connection, distinct from that used to
  deliver the original AS2 message.  When handling an asynchronous
  request, the HTTP response MUST be sent back before the MDN is
  processed and sent on the separate connection.





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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  When an asynchronous AS2-MDN is requested by the sender of an AS2
  message, the synchronous HTTP or HTTPS response returned to the
  sender prior to terminating the connection MUST be a transfer-layer
  response indicating the success or failure of the data transfer.  The
  format of such a synchronous response MAY be the same as that
  response returned when no AS2-MDN is requested.

  The following diagram illustrates the synchronous versus asynchronous
  varieties of AS2-MDN delivery using HTTP:

  Synchronous AS2-MDN

  [Peer1] ----( connect )----> [Peer2]
  [Peer1] -----( send )------> [Peer2]   [HTTP Request [AS2-Message]]
  [Peer1] <---( receive )----- [Peer2]   [HTTP Response [AS2-MDN]]

  Asynchronous AS2-MDN

  [Peer1] ----( connect )----> [Peer2]
  [Peer1] -----( send )------> [Peer2]   [HTTP Request [AS2-Message]]
  [Peer1] <---( receive )----- [Peer2]   [HTTP Response]

  [Peer1]*<---( connect )----- [Peer2]
  [Peer1] <--- ( send )------- [Peer2]   [HTTP Request [AS2-MDN]]
  [Peer1] ----( receive )----> [Peer2]   [HTTP Response]

  * Note: An AS2-MDN may be directed to a host different from that of
  the sender of the AS2 message.  It may utilize a transfer protocol
  different from that used to send the original AS2 message.

  The advantage of the synchronous MDN is that it can provide the
  sender of the AS2 Message with a verifiable confirmation of message
  delivery within a synchronous logic flow.  However, if the message is
  relatively large, the time required to process this message and to
  return an AS2-MDN to the sender on the same TCP/IP connection may
  exceed the maximum configured time permitted for an IP connection.

  The advantage of the asynchronous MDN is that it provides for the
  rapid return of a transfer-layer response from the receiver,
  confirming the receipt of data, therefore not requiring that a TCP/IP
  connection necessarily remain open for very long.  However, this
  design requires that the asynchronous AS2-MDN contain enough
  information to identify the original message uniquely so that, when
  received by the AS2 Message originator, the status of the original
  AS2 Message can be properly updated based on the contents of the
  AS2-MDN.





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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  Synchronous or asynchronous HTTP or HTTPS MDNs are handled according
  to the requirements of this specification.

  However, SMTP MDNs are formatted according to the requirements of RFC
  3335 [4].

7.3.  Requesting a Signed Receipt

  Message disposition notifications are requested as per RFC 3798.  A
  request that the receiving user agent issue a message disposition
  notification is made by placing the following header into the message
  to be sent:

       MDN-request-header = "Disposition-notification-to"
                           ":"  mail-address

  The following example is for requesting an MDN:

       Disposition-notification-to: [email protected]

  This syntax is a residue of the use of MDNs using SMTP transfer.
  Because this specification is adjusting the functionality from SMTP
  to HTTP while retaining as much as possible from the [4]
  functionality, the mail-address MUST be present.  The mail-address
  field is specified as an RFC 2822 localpart@domain [addr-spec]
  address.  However, the address is not used to identify where to
  return the MDN.  Receiving applications MUST ignore the value and
  MUST not complain about RFC 2822 address syntax violations.

  When requesting MDN-based receipts, the originator supplies
  additional extension headers that precede the message body.  These
  header "tags" are as follows:

  A Message-ID header is added to support message reconciliation, so
  that an Original-Message-Id value can be returned in the body part of
  MDN.  Other headers, especially "Subject" and "Date", SHOULD be
  supplied; the values of these headers are often mentioned in the
  human-readable section of a MDN to aid in identifying the original
  message.

  MDNs will be returned in the HTTP response when requested, unless an
  asynchronous return is requested.

  To request an asynchronous message disposition notification, the
  following header is placed into the message that is sent:

       Receipt-Delivery-Option: return-URL




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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  Here is an example requesting that the MDN be asynchronous:

       Receipt-Delivery-Option: http://www.example.com/Path

  Receipt-delivery-option syntax allows return-url to use some schemes
  other than HTTP using the POST method.

  The "receipt-delivery-option: return-url" string indicates the URL to
  use for an asynchronous MDN.  This header is NOT present if the
  receipt is to be synchronous.  The email value in Disposition-
  notification-to is not used in this specification because it was
  limited to RFC 2822 addresses; the extension header "Receipt-
  delivery-option" has been introduced to provide a URL for the MDN
  return by several transfer options.

  The receipt-delivery-option's value MUST be a URL indicating the
  delivery transport destination for the receipt.

  An example request for an asynchronous MDN via an HTTP transport:

       Receipt-delivery-option: http://www.example.com

  An example request for an asynchronous MDN via an HTTP/S transport:

       Receipt-delivery-option: https://www.example.com

  An example request for an asynchronous MDN via an SMTP transport:

       Receipt-delivery-option: mailto:[email protected]

  For more information on requesting SMTP MDNs, refer to RFC 3335 [4].

  Finally, the header, Disposition-notification-options, identifies
  characteristics of message disposition notification as in [5].  The
  most important of these options is for indicating the signing options
  for the MDN, as in the following example:

       Disposition-notification-options:
            signed-receipt-protocol=optional,pkcs7-signature;
            signed-receipt-micalg=optional,sha1,md5

  For signing options, consider the disposition-notification-options
  syntax:

       Disposition-notification-options =
                "Disposition-Notification-Options" ":"
                 disposition-notification-parameters




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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


   where
            disposition-notification-parameters =
                              parameter *(";" parameter)

   where
            parameter = attribute "=" importance ", " 1#value"

   where
            importance = "required" | "optional"

  So the Disposition-notification-options string could be:

       signed-receipt-protocol=optional,<protocol symbol>;
       signed-receipt-micalg=optional,<micalg1>,<micalg2>,...;

  The currently used value for <protocol symbol> is "pkcs7-signature"
  for the S/MIME detached signature format.

  The currently supported values for MIC algorithm <micalg> values are:

       Algorithm   Value Used
       ---------    -------
        SHA-1        sha1
        MD5          md5

  The semantics of the "signed-receipt-protocol" and the "signed-
  receipt-micalg" parameters are as follows:

  1. The "signed-receipt-protocol" parameter is used to request a
     signed receipt from the recipient trading partner.  The "signed-
     receipt-protocol" parameter also specifies the format in which the
     signed receipt SHOULD be returned to the requester.

     The "signed-receipt-micalg" parameter is a list of MIC algorithms
     preferred by the requester for use in signing the returned
     receipt.  The list of MIC algorithms SHOULD be honored by the
     recipient from left to right.

     Both the "signed-receipt-protocol" and the "signed- receipt-
     micalg" option parameters are REQUIRED when requesting a signed
     receipt.

     The lack of the presence of the "Receipt-Delivery-Option"
     indicates that a receipt is synchronous in nature.  The presence
     of the "Receipt-Delivery-Option: return-url" indicates that an
     asynchronous receipt is requested and SHOULD be sent to the
     "return-url".




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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  2. The "importance" attribute of "Optional" is defined in RFC 3798,
     Section 2.2, and has the following meaning:

     Parameters with an importance of "Optional" permit a UA that does
     not understand the particular options parameter to still generate
     an MDN in response to a request for a MDN.

     A UA that does not understand the "signed-receipt-protocol"
     parameter or the "signed-receipt-micalg" will obviously not return
     a signed receipt.

     The importance of "Optional" is used for the signed receipt
     parameters because it is RECOMMENDED that an MDN be returned to
     the requesting trading partner even if the recipient could not
     sign it.

     The returned MDN will contain information on the disposition of
     the message and on why the MDN could not be signed.  See the
     Disposition field in Section 7.5 for more information.

     Within an EDI trading relationship, if a signed receipt is
     expected and is not returned, then the validity of the transaction
     is up to the trading partners to resolve.

     In general, if a signed receipt is required in the trading
     relationship and is not received, the transaction will likely not
     be considered valid.

7.3.1.  Signed Receipt Considerations

  The method used to request a receipt or a signed receipt is defined
  in RFC 3798, "An Extensible Message Format for Message Disposition
  Notifications".

  The "rules" are as follows:

  1. When a receipt is requested, explicitly specifying that the
     receipt be signed, then the receipt MUST be returned with a
     signature.

  2. When a receipt is requested, explicitly specifying that the
     receipt be signed, but the recipient cannot support either the
     requested protocol format or the requested MIC algorithms, then
     either a signed or unsigned receipt SHOULD be returned.







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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  3. When a signature is not explicitly requested, or if the signed
     receipt request parameter is not recognized by the UA, then no
     receipt, an unsigned receipt, or a signed receipt MAY be returned
     by the recipient.

  NOTE: For Internet EDI, it is RECOMMENDED that when a signature is
  not explicitly requested, or if parameters are not recognized, the UA
  send back, at a minimum, an unsigned receipt.  If, however, a signed
  receipt was always returned as a policy, whether requested or not,
  then any false unsigned receipts can be repudiated.

  When a request for a signed receipt is made, but there is an error in
  processing the contents of the message, a signed receipt MUST still
  be returned.  The request for a signed receipt SHALL still be
  honored, though the transaction itself may not be valid.  The reason
  why the contents could not be processed MUST be set in the
  "disposition-field".

  When a signed receipt request is made, the "Received-content-MIC"
  MUST always be returned to the requester (except when corruption
  prevents computation of the digest in accordance with the following
  specification).  The "Received-content-MIC" MUST be calculated as
  follows:

     o  For any signed messages, the MIC to be returned is calculated
        on the RFC1767/RFC3023 MIME header and content.
        Canonicalization on the MIME headers MUST be performed before
        the MIC is calculated, since the sender requesting the signed
        receipt was also REQUIRED to canonicalize.

     o  For encrypted, unsigned messages, the MIC to be returned is
        calculated on the decrypted RFC 1767/RFC3023 MIME header and
        content.  The content after decryption MUST be canonicalized
        before the MIC is calculated.

     o  For unsigned, unencrypted messages, the MIC MUST be calculated
        over the message contents without the MIME or any other RFC
        2822 headers, since these are sometimes altered or reordered by
        Mail Transport Agents (MTAs).

7.4.  MDN Format and Values

  This section defines the format of the AS2 Message Disposition
  Notification (AS2-MDN).







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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


7.4.1.  AS2-MDN General Formats

  The AS2-MDN follows the MDN specification [5] except where noted in
  this section.  The modified ABNF definitions in this document use the
  vertical-bar character, '|', to denote a logical "OR" construction.
  This usage follows RFC 2616 [3].  HTTP entities referred to below are
  not further defined in this document.  Refer to RFC 2616 [3] for
  complete definitions of HTTP entities.  The format of the AS2-MDN is:

  AS2-MDN = AS2-sync-MDN | AS2-async-http-MDN |
      AS2-async-smtp-MDN

  AS2-sync-MDN =
      Status-Line
      *(( general-header | response-header | entity-header )
      CRLF )
      CRLF
      AS2-MDN-body

  Status-Line =
      HTTP-Version SP Status-Code SP Reason-Phrase CRLF

  AS2-async-http-MDN =
      Request-Line
      *(( general-header | request-header | entity-header )
      CRLF )
      CRLF
      AS2-MDN-body

  Request-Line =
      Method SP Request-URI SP HTTP-Version CRLF

  AS2-async-smtp-MDN =
      *(( general-header | request-header | entity-header )
      CRLF )
      CRLF
      AS2-MDN-body

  AS2-MDN-body =
      AS2-signed-MDN-body | AS2-unsigned-MDN-body

7.4.2.  AS2-MDN Construction

  The AS2-MDN-body is formatted as a MIME multipart/report with a
  report-type of "disposition-notification".  When the message is
  unsigned, the transfer-layer ("outermost") entity-headers of the
  AS2-MDN contain the content-type header that specifies a content-type




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  of "multipart/report" and parameters indicating the report-type, and
  the value of the outermost multipart boundary.

  When the AS2-MDN is signed, the transfer-layer ("outermost") entity-
  headers of the AS2-MDN contain a content-type header that specifies a
  content-type of "multipart/signed" and parameters indicating the
  algorithm used to compute the message digest, the signature-
  formatting protocol (e.g., pkcs7-signature), and the value of the
  outermost multipart boundary.  The first part of the MIME
  multipart/signed message is an embedded MIME multipart/report of type
  "disposition-notification".  The second part of the multipart/signed
  message contains a MIME application/pkcs7-signature message.

  The first part of the MIME multipart/report is a "human-readable"
  portion that contains a general description of the message
  disposition.  The second part of the MIME multipart/report is a
  "machine-readable" portion that is defined as:

  AS2-disposition-notification-content =
      [ reporting-ua-field CRLF ]
      [ mdn-gateway-field CRLF ]
      final-recipient-field CRLF
      [ original-message-id-field CRLF ]
      AS2-disposition-field CRLF
      *( failure-field CRLF )
      *( error-field CRLF )
      *( warning-field CRLF )
      *( extension-field CRLF )
      [ AS2-received-content-MIC-field CRLF ]

7.4.3.  AS2-MDN Fields

  The rules for constructing the AS2-disposition-notification content
  are identical to the disposition-notification-content rules provided
  in Section 7 of RFC 3798 [5], except that the RFC 3798 disposition-
  field has been replaced with the AS2-disposition-field and that the
  AS2-received-content-MIC field has been added.  The differences
  between the RFC 3798 disposition-field and the AS2-disposition-field
  are described below.  Where there are differences between this
  document and RFC 3798, those entity names have been changed by pre-
  pending "AS2-".  Entities that do not differ from RFC 3798 are not
  necessarily further defined in this document; refer to RFC 3798,
  Section 7, "Collected Grammar", for the original grammar.








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  AS2-disposition-field =
      "Disposition" ":" disposition-mode ";"
      AS2-disposition-type [ '/' AS2-disposition-modifier ]

  disposition-mode =
      action-mode "/" sending-mode

  action-mode =
      "manual-action" | "automatic-action"

  sending-mode =
      "MDN-sent-manually" | "MDN-sent-automatically"

  AS2-disposition-type =
      "processed" | "failed"

  AS2-disposition-modifier =
      ( "error" | "warning" ) | AS2-disposition-modifier-extension

  AS2-disposition-modifier-extension =
      "error: authentication-failed" |
      "error: decompression-failed" |
      "error: decryption-failed" |
      "error: insufficient-message-security" |
      "error: integrity-check-failed" |
      "error: unexpected-processing-error" |
      "warning: " AS2-MDN-warning-description |
      "failure: " AS2-MDN-failure-description

  AS2-MDN-warning-description = *( TEXT )

  AS2-MDN-failure-description = *( TEXT )

  AS2-received-content-MIC-field =
      "Received-content-MIC" ":" encoded-message-digest ","
      digest-alg-id CRLF

  encoded-message-digest =
      1*( 'A'-Z' | 'a'-'z' | '0'-'9' | '/' | '+' | '=' )  (
      i.e. base64( message-digest ) )

  digest-alg-id = "sha1" | "md5"

  "Insufficient-message-security" and "decompression-failed" are new
  error codes that are not mentioned in the AS1 RFC 3335, and may not
  be compatible with earlier implementations of AS2.





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  The "Received-content-MIC" extension field is set when the integrity
  of the received message is verified.  The MIC is the base64-encoded
  message-digest computed over the received message with a hash
  function.  This field is required for signed receipts but optional
  for unsigned receipts.  For details defining the specific content
  over which the message digest is to be computed, see Section 7.3.1 of
  this document.

  For signed messages, the algorithm used to calculate the MIC MUST be
  the same as that used on the message that was signed.  If the message
  is not signed, then the SHA-1 algorithm SHOULD be used.  This field
  is set only when the contents of the message are processed
  successfully.  This field is used in conjunction with the recipient's
  signature on the MDN so that the sender can verify non-repudiation of
  receipt.

  AS2-MDN field names (e.g., "Disposition:", "Final-Recipient:") are
  case insensitive (cf. RFC 3798, Section 3.1.1).  AS2-MDN action-
  modes, sending-modes, AS2-disposition-types, and AS2-disposition-
  modifier values, which are defined above, and user-supplied *( TEXT )
  values are also case insensitive.  AS2 implementations MUST NOT make
  assumptions regarding the values supplied for AS2-MDN-warning-
  description or AS2-MDN-failure-description, or for the values of any
  (optional) error, warning, or failure fields.

7.4.4.  Additional AS2-MDN Programming Notes

  o  Unlike SMTP, for HTTP transactions, Original-Recipient and Final-
     Recipient SHOULD not be different.  The value in Original-
     Message-ID SHOULD match the original Message-ID header value.

  o  Refer to RFC 3798 for the formatting of the MDN, except for the
     specific deviations mentioned above.

  o  Refer to RFC 3462 and RFC 3798 for the formatting of the content-
     type entity-headers for the MDN.

  o  Use an action-mode of "automatic-action" when the disposition
     described by the disposition type was a result of an automatic
     action rather than that of an explicit instruction by the user for
     this message.

  o  Use an action-mode of "manual-action" when the disposition
     described by the disposition type was a result of an explicit
     instruction by the user rather than some sort of automatically
     performed action.





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  o  Use a sending-mode of "MDN-sent-automatically" when the MDN is
     sent because the UA had previously been configured to do so.

  o  Use a sending-mode of "MDN-sent-manually" when the user explicitly
     gave permission for this particular MDN to be sent.

  o  The sending-mode "MDN-sent-manually" is meaningful ONLY with
     "manual-action", not with "automatic-action".

  o  The "failed" disposition type MUST NOT be used for the situation
     in which there is some problem in processing the message other
     than interpreting the request for an MDN.  The "processed" or
     other disposition type with appropriate disposition modifiers is
     to be used in such situations.

7.5.  Disposition Mode, Type, and Modifier

7.5.1.  Disposition Mode Overview

  This section provides a brief overview of how "processed", "error",
  "failure", and "warning" are used.

7.5.2.  Successful Processing Status Indication

  When the request for a receipt or signed receipt, and the received
  message contents are successfully processed by the receiving EDI UA,
  a receipt or MDN SHOULD be returned with the disposition-type set to
  "processed".  When the MDN is sent automatically by the EDI UA, and
  there is no explicit way for a user to control the sending of the
  MDN, then the first part of the "disposition-mode" SHOULD be set to
  "automatic-action".  When the MDN is being sent under user-
  configurable control, then the first part of the "disposition-mode"
  SHOULD be set to "manual-action".  Since a request for a signed
  receipt should always be honored, the user MUST not be allowed to
  configure the UA not to send a signed receipt when the sender
  requests one.

  The second part of the disposition-mode is set to "MDN-sent-manually"
  if the user gave explicit permission for the MDN to be sent.  Again,
  the user MUST not be allowed to explicitly refuse to send a signed
  receipt when the sender requests one.  The second part of the
  "disposition-mode" is set to "MDN-sent-automatically" whenever the
  EDI UA sends the MDN automatically, regardless of whether the sending
  was under the control of a user, administrator, or software.

  Because EDI content is generally handled automatically by the EDI UA,
  a request for a receipt or signed receipt will generally return the
  following in the "disposition-field":



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      Disposition: automatic-action/MDN-sent-automatically; processed

  Note that this specification does not restrict the use of the
  "disposition-mode" just to automatic actions.  Manual actions are
  valid as long as it is kept in mind that a request for a signed
  receipt MUST be honored.

7.5.3.  Unsuccessful Processed Content

  The request for a signed receipt requires the use of two
  "disposition-notification-options", which specify the protocol format
  of the returned signed receipt, and the MIC algorithm used to
  calculate the MIC over the message contents.  The "disposition-field"
  values that should be used if the message content is being rejected
  or ignored (for instance, if the EDI UA determines that a signed
  receipt cannot be returned because it does not support the requested
  protocol format, the EDI UA chooses not to process the message
  contents itself) MUST be specified in the MDN "disposition-field" as
  follows:

      Disposition: "disposition-mode";  failed/Failure:
       unsupported format

  The "failed" AS2-disposition-type MUST be used when a failure occurs
  that prevents the proper generation of an MDN.  For example, this
  disposition-type would apply if the sender of the message requested
  the application of an unsupported message-integrity-check (MIC)
  algorithm.

  The "failure:" AS2-disposition-modifier-extension SHOULD be used with
  an implementation-defined description of the failure.  Further
  information about the failure may be contained in a failure-field.

  The syntax of the "failed" disposition-type is general, allowing the
  sending of any textual information along with the "failed"
  disposition-type.  Implementations MUST support any printable textual
  characters after the Failure disposition-type.  For use in Internet
  EDI, the following "failed" values are pre-defined and MUST be
  supported:

      "Failure: unsupported format"

      "Failure: unsupported MIC-algorithms"








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7.5.4.  Unsuccessful Non-Content Processing

  When errors occur in processing the received message (other than
  content), the "disposition-field" MUST be set to the "processed"
  value for disposition-type and the "error" value for disposition-
  modifier.

  The "error" AS2-disposition-modifier with the "processed"
  disposition-type MUST be used to indicate that an error of some sort
  occurred that prevented successful processing of the message.
  Further information may be contained in an error-field.

  An "error:" AS2-disposition-modifier-extension SHOULD be used to
  combine the indication of an error with a predefined description of a
  specific, well-known error.  Further information about the error may
  be contained in an error field.

  For internet EDI use, the following "error" AS2-disposition-modifier
  values are defined:

  o "Error: decryption-failed"           - the receiver could not
                                           decrypt the message
                                           contents.

  o "Error: authentication-failed"       - the receiver could not
                                           authenticate the sender.

  o "Error: integrity-check-failed"      - the receiver could not
                                           verify content integrity.

  o "Error: unexpected-processing-error" - a catch-all for any
                                           additional processing
                                           errors.

  An example of how the "disposition-field" would look when errors
  other than those in content processing are detected is as follows:

      Disposition: "disposition-mode"; processed/Error:
        decryption-failed

7.5.5.  Processing Warnings

  Situations arise in EDI when, even if a trading partner cannot be
  authenticated correctly, the trading partners still agree to continue
  processing the EDI transactions.  Transaction reconciliation is done
  between the trading partners at a later time.  In the content





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  processing warning situations as described above, the "disposition-
  field" MUST be set to the "processed" disposition-type value, and the
  "warning" to the "disposition-modifier" value.

  The "warning" AS2-disposition-modifier MUST be used with the
  "processed" disposition-type to indicate that the message was
  successfully processed but that an exceptional condition occurred.
  Further information may be contained in a warning-field.

  A "warning:" AS2-disposition-modifier-extension SHOULD be used to
  combine the indication of a warning with an implementation-defined
  description of the warning.  Further information about the warning
  may be contained in a warning-field.

  For use in Internet EDI, the following "warning"
  disposition-modifier-extension value is defined:

      "Warning: authentication-failed, processing continued"

  An example of how the "disposition-field" would look when warning
  other than those for content processing are detected is as follows:

  Example:

      Disposition: "disposition-mode"; processed/Warning:
        authentication-failed, processing continued

7.5.6.  Backward Compatibility with Disposition Type, Modifier, and
       Extension

  The following set of examples represents typical constructions of the
  Disposition field that have been in use by AS2 implementations.  This
  is NOT an exhaustive list of possible constructions.  However, AS2
  implementations MUST accept constructions of this type to be backward
  compatible with earlier AS2 versions.

     Disposition: automatic-action/MDN-sent-automatically; processed

     Disposition: automatic-action/MDN-sent-automatically;
     processed/error: authentication-failed

     Disposition: automatic-action/MDN-sent-automatically;
     processed/warning: duplicate-document

     Disposition: automatic-action/MDN-sent-automatically;
     failed/failure: sender-equals-receiver





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  The following set of examples represents allowable constructions of
  the Disposition field that combine the historic constructions above
  with optional RFC 3798 error, warning, and failure fields.  AS2
  implementations MAY produce these constructions.  However, AS2
  servers are not required to recognize or process optional error,
  warning, or failure fields at this time.  Note that the use of the
  multiple error fields in the second example below provides for the
  indication of multiple error conditions.

     Disposition: automatic-action/MDN-sent-automatically; processed

     Disposition: automatic-action/MDN-sent-automatically;
       processed/error: decryption-failed
     Error: The signature did not decrypt into a valid PKCS#1
       Type-2 block.
     Error: The length of the decrypted key does not equal the
       octet length of the modulus.

     Disposition: automatic-action/MDN-sent-automatically;
       processed/warning: duplicate-document
     Warning: An identical message already exists at the
       destination server.

     Disposition: automatic-action/MDN-sent-automatically;
       failed/failure: sender-equals-receiver
     Failure: The AS2-To name is identical to the AS2-From name.

  The following set of examples represents allowable constructions of
  the Disposition field that employ pure RFC 3798 Disposition-modifiers
  with optional error, warning, and failure fields.  These examples are
  provided as informational only.  These constructions are not
  guaranteed to be backward compatible with AS2 implementations prior
  to version 1.1.

     Disposition: automatic-action/MDN-sent-automatically; processed

     Disposition: automatic-action/MDN-sent-automatically;
       processed/error
     Error: authentication-failed
     Error: The signature did not decrypt into a valid PKCS#1 Type-2
       block.
     Error: The length of the decrypted key does not equal the
       octet length of the modulus.

     Disposition: automatic-action/MDN-sent-automatically;
       processed/warning
     Warning: duplicate-document




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     Disposition: automatic-action/MDN-sent-automatically; failed
     Failure: sender-equals-receiver

7.6.  Receipt Reply Considerations in an HTTP POST

  The details of the response to the POST command vary depending upon
  whether a receipt has been requested.

  With no extended header requesting a receipt, and with no errors
  accessing the request-URI specified processing, the status line in
  the Response to the POST request SHOULD be in the 200 range.  Status
  codes in the 200 range SHOULD also be used when an entity is returned
  (a signed receipt in a multipart/signed content type or an unsigned
  receipt in a multipart/report).  Even when the disposition of the
  data was an error condition at the authentication, decryption or
  other higher level, the HTTP status code SHOULD indicate success at
  the HTTP level.

  The HTTP server-side application may respond with an unsolicited
  multipart/report as a message body that the HTTP client might not
  have solicited, but the client may discard this.  Applications SHOULD
  avoid emitting unsolicited receipt replies because bandwidth or
  processing limitations might have led administrators to suspend
  asking for acknowledgements.

  Message Disposition Notifications, when used in the HTTP reply
  context, will closely parallel a SMTP MDN.  For example, the
  disposition field is a required element in the machine-readable
  second part of a multipart/report for a MDN.  The final-recipient-
  field ([5], Section 3.1) value SHOULD be derived from the entity
  headers of the request.

  In an MDN, the first part of the multipart/report (the human-readable
  part) SHOULD include items such as the subject, the date, and other
  information when those fields are present in entity header fields
  following the POST request.  An application MUST report the Message-
  ID of the request in the second part of the multipart/report (the
  machine-readable part).  Also, an MDN SHOULD have its own unique
  Message-ID HTTP header.  The HTTP reply SHOULD normally omit the
  third optional part of the multipart/report (used to return the
  original message or its headers in the SMTP context).

8.  Public Key Certificate Handling

  In the near term, the exchange of public keys and certification of
  these keys MUST be handled as part of the process of establishing a
  trading partnership.  The UA and/or EDI application interface must
  maintain a database of public keys used for encryption or signatures,



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  in addition to the mapping between the EDI trading partner ID and the
  RFC 2822 [9] email address and HTTP URL/URI.  The procedures for
  establishing a trading partnership and configuring the secure EDI
  messaging system might vary among trading partners and software
  packages.

  X.509 certificates are REQUIRED.  It is RECOMMENDED that trading
  partners self-certify each other if an agreed-upon certification
  authority is not used.  This applicability statement does NOT require
  the use of a certification authority.  The use of a certification
  authority is therefore OPTIONAL.  Certificates may be self-signed.

  It is RECOMMENDED that when trading partners are using S/MIME they
  also exchange public key certificates, considering advice provided in
  [12].

  The message formats useful for certificate exchange are found in [7]
  and [13].

  In the long term, additional standards may be developed to simplify
  the process of establishing a trading partnership, including the
  third-party authentication of trading partners, as well as the
  attributes of the trading relationship.

9.  Security Considerations

  This entire document is concerned with secure transport of business
  to business data, and it considers both data confidentiality and
  authentication issues.

  Extracted from RFC 3851 [7]:
  40-bit encryption is considered weak by most cryptographers.  Using
  weak cryptography in S/MIME offers little actual security over
  sending plaintext.  However, other features of S/MIME, such as the
  specification of Triple DES and the ability to announce stronger
  cryptographic capabilities to parties with whom you communicate,
  allow senders to create messages that use strong encryption.  Using
  weak cryptography is never recommended unless the only alternative is
  no cryptography.  When feasible, sending and receiving agents SHOULD
  inform senders and recipients of the relative cryptographic strength
  of messages.

  Extracted from RFC 3850 [12]:
  When processing certificates, there are many situations where the
  processing might fail.  Because the processing may be done by a user
  agent, a security gateway, or other program, there is no single way
  to handle such failures.  Just because the methods to handle the
  failures have not been listed, however, the reader should not assume



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  that they are not important.  The opposite is true: if a certificate
  is not provably valid and associated with the message, the processing
  software should take immediate and noticeable steps to inform the end
  user about it.

  Some of the many situations in which signature and certificate
  checking might fail include the following:

     o  No certificate chain leads to a trusted CA.

     o  No ability to check the Certificate Revocation List (CRL) for a
        certificate.

     o  An invalid CRL was received.

     o  The CRL being checked is expired.

     o  The certificate is expired.

     o  The certificate has been revoked.

  There are certainly other instances where a certificate may be
  invalid, and it is the responsibility of the processing software to
  check them all thoroughly, and to decide what to do if the check
  fails.  See RFC 3280 for additional information on certificate path
  validation.

  The following are additional security considerations to those listed
  in [7] and [12].

9.1.  NRR Cautions

  This specification seeks to provide multiple mechanisms that can be
  combined in accordance with local policies to achieve a wide range of
  security needs as determined by threat and risk analyses of the
  business peers.  It is required that all these mechanisms be
  implemented by AS2 software so that the software has capabilities
  that promote strong interoperability, no matter what policies are
  adopted.

  One strong cluster of mechanisms (the secure transmission loop) can
  provide good support for meeting the evidentiary needs of non-
  repudiation of receipt by the original sender and by a third party
  supplied with all stated evidence.  However, this specification does
  not itself define non-repudiation of receipt nor enumerate its
  essential properties because NRR is a business analysis and/or legal
  requirement, and not relevantly defined by a technical applicability
  statement.



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  Some analyses observe that non-repudiation of receipt presupposes
  that non-repudiation of the sender of the original message is
  obtained, and further that non-repudiation should be implemented by
  means of digital signature on the original message.  To satisfy
  strict NRR evidence, authentication and integrity MUST be provided by
  some mechanism, and the RECOMMENDED mechanism is digital signatures
  on both the original message and the receipt message.

  Given that this specification has selected several mechanisms that
  can be combined in several ways, it is important to realize that if a
  digital signature is omitted from the original message, in order to
  satisfy the preceding analysis of NRR requirements, some
  authentication mechanism MUST accompany the request for a signed
  receipt and its included Received-content-MIC value.  This
  authentication might come from using client-side SSL, authentication
  via IPsec, or HTTP authentication (while using SSL).  In any case,
  records of the message content, its security basis, and the digest
  value need to be retained for the NRR process.

  Therefore, if NRR is one of the goals of the policy that is adopted,
  by using the mechanisms of the secure transmission loop mentioned
  above and by retaining appropriate records of authentication at the
  original message sender site, strong evidentiary requirements
  proposed for NRR can be fulfilled.

  Other ways of proceeding may fall short of fulfilling the most
  stringent sets of evidence required for NRR to obtain, but may
  nevertheless be part of a commercial trading agreement and, as such,
  are good enough for the parties involved.  However, if MDNs are
  returned unsigned, evidentiary requirements for NRR are weak; some
  authentication of the identity of the receiver is needed.

9.2.  HTTPS Remark

  The following certificate types MUST be supported for SSL server-side
  certificates:

     o  with URL in the Distinguished Name Common Name attribute

     o  without URL in the Distinguished Name Common Name attribute

     o  self-signed (self-issued)

     o  certification authority certified

  The URL, which matches the source server identity, SHOULD be carried
  in the certificate.  However, it is not required that DNS checks or
  reverse lookups to vouch for the accuracy of the URL or server value.



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  Because server-side certificates are exchanged, and also trust is
  established during the configuration of the trading partner
  relationship, runtime checks are not required by implementations of
  this specification.

  The complete certification chain MUST be included in all
  certificates.  All certificate verifications MUST "chain to root" or
  to an accepted trust anchor.  Additionally, the certificate hash
  SHOULD match the hash recomputed by the receiver.

9.3.  Replay Remark

  Because business data documents normally contain transaction ids,
  replays (such as resends of not-yet-acknowledged messages) are
  discarded as part of the normal process of duplicate detection.
  Detection of duplicates by Message-Id or by business transaction
  identifiers is recommended.

10.  IANA Considerations

  RFC 3335 registered two Disposition-Notification-Options parameters

     Parameter-name: signed-receipt-protocol
     Parameter-name: signed-receipt-micalg

  that are also used by this specification (see Section 7.3).

  RFC 3335 also registered on MDN Extension field name

     Extension field name: Received-content-MIC

  that is also used by this specification (see Section 7.4.3).
  Registration of the above is therefore NOT needed.

10.1.  Registration

  This specification defines an extension to the Message Disposition
  Notification (MDN) protocol for a disposition-modifier in the
  Disposition field of a body of content-type "message/disposition-
  notification".

10.1.1.  Disposition Modifier 'warning'

  Parameter-name:  warning
  Semantics: See Sections 7.4.3 and 7.5.5 of this document.






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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


11.  Acknowledgements

  Carl Hage, Karen Rosenfeld, Chuck Fenton, and many others have
  provided valuable suggestions that improved this applicability
  statement.  The authors would also like to thank the vendors who
  participated in the Drummond Group Inc. AS2 interoperability testing.
  Their contributions led to great improvement in the clarity of this
  document.

12.  References

12.1.  Normative References

  [1]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
       Extensions (MIME) Part One: Format of Internet Message Bodies",
       RFC 2045, November 1996.

       Freed, N. and N. Borenstein, "Multipurpose Internet Mail
       Extensions (MIME) Part Two: Media Types", RFC 2046, November
       1996.

       Freed, N. and N. Borenstein, "Multipurpose Internet Mail
       Extensions (MIME) Part Five: Conformance Criteria and Examples",
       RFC 2049, November 1996.

  [2]  Crocker, D., "MIME Encapsulation of EDI Objects", RFC 1767,
       March 1995.

  [3]  Fielding,  R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L.,
       Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol --
       HTTP/1.1", RFC 2616, June 1999.

  [4]  Harding, T., Drummond, R., and C. Shih, "MIME-based Secure
       Peer-to-Peer Business Data Interchange over the Internet", RFC
       3335, September 2002.

  [5]  Hansen, T. and G. Vaudreuil, "Message Disposition Notification",
       RFC 3798, May 2004.

  [6]  Galvin, J., Murphy, S., Crocker, S., and N. Freed, "Security
       Multiparts for MIME: Multipart/Signed and Multipart/Encrypted",
       RFC 1847, October 1995.

  [7]  Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions
       (S/MIME) Version 3.1 Message Specification", RFC 3851, July
       2004.





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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  [8]  Vaudreuil, G., "The Multipart/Report Content Type for the
       Reporting of Mail System Administrative Messages", RFC 3462,
       January 2003.

  [9]  Resnick, P., "Internet Message Format", RFC 2822, April 2001.

  [10] Murata, M., Laurent, S. St., and D. Kohn, "XML Media Types", RFC
       3023, January 2001.

  [11] Bradner, S., "The Internet Standards Process -- Revision 3", BCP
       9, RFC 2026, October 1996.

  [12] Ramsdell, B., "Secure/Multipurpose Internet Mail Extensions
       (S/MIME) Version 3.1 Certificate Handling", RFC 3850, July 2004.

  [13] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3852,
       July 2004.

  [14] Crocker, D. and P. Overell, "Augmented BNF for Syntax
       Specifications: ABNF", RFC 2234, November 1997.

12.2.  Informative References

  [15] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC
       2246, January 1999.


























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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


Appendix A:  Message Examples

  NOTE: All examples are provided for illustration only, and are not
  considered part of the protocol specification.  If an example
  conflicts with the protocol definitions specified above or in the
  other referenced RFCs, the example is wrong.

A.1.  Signed Message Requesting a Signed, Synchronous Receipt

  POST /receive HTTP/1.0
  Host: 10.234.160.12:80
  User-Agent: AS2 Company Server
  Date: Wed, 31 Jul 2002 13:34:50 GMT
  From: [email protected]
  AS2-Version: 1.1
  AS2-From: "\"  as2Name  \""
  AS2-To: 0123456780000
  Subject: Test Case
  Message-Id: <200207310834482A70BF63@\"~~foo~~\">
  Disposition-Notification-To: [email protected]
  Disposition-Notification-Options: signed-receipt-protocol=optional,
    pkcs7-signature; signed-receipt-micalg=optional,sha1
  Content-Type: multipart/signed; boundary="as2BouNdary1as2";
    protocol="application/pkcs7-signature"; micalg=sha1
  Content-Length: 2464

  --as2BouNdary1as2
  Content-Type: application/edi-x12
  Content-Disposition: Attachment; filename=rfc1767.dat
    [ISA ...EDI transaction data...IEA...]

  --as2BouNdary1as2
  Content-Type: application/pkcs7-signature

    [omitted binary pkcs7 signature data]
  --as2BouNdary1as2--

A.2.  MDN for Message A.1, Above

  HTTP/1.0 200 OK
  AS2-From: 0123456780000
  AS2-To: "\"  as2Name  \""
  AS2-Version: 1.1
  Message-ID: <709700825.1028122454671.JavaMail@ediXchange>
  Content-Type: multipart/signed; micalg=sha1;
       protocol="application/pkcs7-signature";
       boundary="----=_Part_57_648441049.1028122454671"
  Connection: Close



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  Content-Length: 1980

  ------=_Part_57_648441049.1028122454671

  & Content-Type: multipart/report;
  & Report-Type=disposition-notification;
  &    boundary="----=_Part_56_1672293592.1028122454656"
  &
  &------=_Part_56_1672293592.1028122454656
  &Content-Type: text/plain
  &Content-Transfer-Encoding: 7bit
  &
  &MDN for -
  & Message ID: <200207310834482A70BF63@\"~~foo~~\">
  &  From: "\"  as2Name  \""
  &  To: "0123456780000"
  &  Received on: 2002-07-31 at 09:34:14 (EDT)
  & Status: processed
  & Comment: This is not a guarantee that the message has
  &  been completely processed or &understood by the receiving
  &  translator
  &
  &------=_Part_56_1672293592.1028122454656
  &Content-Type: message/disposition-notification
  &Content-Transfer-Encoding: 7bit
  &
  &Reporting-UA: AS2 Server
  &Original-Recipient: rfc822; 0123456780000
  &Final-Recipient: rfc822; 0123456780000
  &Original-Message-ID: <200207310834482A70BF63@\"~~foo~~\">
  &Received-content-MIC: 7v7F++fQaNB1sVLFtMRp+dF+eG4=, sha1
  &Disposition: automatic-action/MDN-sent-automatically;
  &  processed
  &
  &------=_Part_56_1672293592.1028122454656--

  ------=_Part_57_648441049.1028122454671
  Content-Type: application/pkcs7-signature; name=smime.p7s
  Content-Transfer-Encoding: base64
  Content-Disposition: attachment; filename=smime.p7s

  MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQ
  cp24hMJNbxDKHnlB9jTiQzLwSwo+/90Pc87x+Sc6EpFSUYWGAAAAAAAA
  ------=_Part_57_648441049.1028122454671--







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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  Notes:

  1. The lines proceeded with "&" are what the signature is calculated
     over.

  2. For details on how to prepare the multipart/signed with protocol =
     "application/pkcs7-signature", see the "S/MIME Message
     Specification, PKCS Security Services for MIME".)

  3. Note that the textual first body part of the multipart/report can
     be used to include a more detailed explanation of the error
     conditions reported by the disposition headers.  The first body
     part of the multipart/report, when used in this way, allows a
     person to better diagnose a problem in detail.

  4. As specified by RFC 3462 [8], returning the original or portions
     of the original message in the third body part of the
     multipart/report is not required.  This is an optional body part.
     However, it is RECOMMENDED that this body part be omitted or left
     blank.

A.3.  Signed, Encrypted Message Requesting a Signed, Asynchronous
     Receipt

  Message-ID: <#as2_company#01#a4260as2_companyout#>
  Date: Thu, 19 Dec 2002 15:04:18 GMT
  From: [email protected]
  Subject: Async MDN request
  Mime-Version: 1.0
  Content-Type: application/pkcs7-mime;
    smime-type=enveloped-data; name=smime.p7m
  Content-Transfer-Encoding: binary
  Content-Disposition: attachment; filename=smime.p7m
  Recipient-Address: 10.240.1.2//
  Disposition-Notification-To:
    http://10.240.1.2:8201/exchange/as2_company
  Disposition-Notification-Options: signed-receipt-protocol=optional,
   pkcs7-signature; signed-receipt-micalg=optional,sha1
  Receipt-Delivery-Option:
    http://10.240.1.2:8201/exchange/as2_company
  AS2-From: as2_company
  AS2-To: "AS2 Test"
  AS2-Version: 1.1
  Host: 10.240.1.2:8101
  Connection: close
  Content-Length: 3428

    [omitted binary encrypted data]



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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


A.4.  Asynchronous MDN for Message A.3, Above

  POST / HTTP/1.1
  Host: 10.240.1.2:8201
  Connection: close, TE
  TE: trailers, deflate, gzip, compress
  User-Agent: RPT-HTTPClient/0.3-3I (Windows 2000)
  Date: Thu, 19 Dec 2002 15:03:38 GMT
  Message-ID: <AS2-20021219_030338@as2_company.dgi_th>
  AS2-Version: 1.1
  Mime-Version: 1.0
  Recipient-Address:
  http://10.240.1.2:8201/exchange/as2_company
  AS2-To: as2_company
  AS2-From: "AS2 Test"
  Subject: Your Requested MDN Response
  From: [email protected]
  Accept-Encoding: deflate, gzip, x-gzip, compress, x-compress
  Content-Type: multipart/signed; micalg=sha1;
    protocol="application/pkcs7-signature";
    boundary="----=_Part_337_6452266.1040310218750"
  Content-Length: 3103

  ------=_Part_337_6452266.1040310218750
  Content-Type: multipart/report;
    report-type=disposition-notification;
    boundary="----=_Part_336_6069110.1040310218718"

  ------=_Part_336_6069110.1040310218718
  Content-Type: text/plain; charset=us-ascii
  Content-Transfer-Encoding: 7bit

  The message <x12.edi> sent to Recipient <AS2 Test> on Thu, 19 Dec
  2002 15:04:18 GMT with Subject <async MDN request> has been received.
  The EDI Interchange was successfully decrypted, and its integrity was
  verified.  In addition, the sender of the message, Sender
  <as2_company> at Location http://10.240.1.2:8201/exchange/as2_company
  was authenticated as the originator of the message.  There is no
  guarantee, however, that the EDI interchange was syntactically
  correct, or that it was received by the EDI application/translator.











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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


  ------=_Part_336_6069110.1040310218718
  Content-Type: message/disposition-notification
  Content-Transfer-Encoding: 7bit

  Reporting-UA: AS2@test:8101
  Original-Recipient: rfc822; "AS2 Test"
  Final-Recipient: rfc822; "AS2 Test"
  Original-Message-ID: <#as2_company#01#a4260as2_companyout#>
  Disposition: automatic-action/MDN-sent-automatically;
    processed
  Received-Content-MIC: Hes6my+vIxIYxmvsA+MNpEOTPAc=, sha1

  ------=_Part_336_6069110.1040310218718--

  ------=_Part_337_6452266.1040310218750
  Content-Type: application/pkcs7-signature; name=smime.p7s
  Content-Transfer-Encoding: base64
  Content-Disposition: attachment; filename=smime.p7s

  BhbWjEfbyXoTAS/H0zpnEqLqbaBh29y2v82b8bdeGw8pipBQWmf53hIcqHGM
  4ZBF3CHw5Wrf1JIE+8TwOzdbal30zeChw88WfRfD7c/j1fIA8sxsujvf2d9j
  UxCUga8BVdVB9kH0Geexytyt0KvWQXfaEEcgZGUAAAAAAAA=

  ------=_Part_337_6452266.1040310218750-

Authors' Addresses

  Dale Moberg
  Cyclone Commerce
  8388 E. Hartford Drive, Suite 100
  Scottsdale, AZ  85255 USA

  EMail: [email protected]


  Rik Drummond
  Drummond Group Inc.
  4700 Bryant Irvin Court, Suite 303
  Fort Worth, TX  76107 USA

  EMail: [email protected]










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RFC 4130     AS2 for Business Data Interchange Using HTTP      July 2005


Full Copyright Statement

  Copyright (C) The Internet Society (2005).

  This document is subject to the rights, licenses and restrictions
  contained in BCP 78, and except as set forth therein, the authors
  retain all their rights.

  This document and the information contained herein are provided on an
  "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
  OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
  ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
  INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
  INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
  WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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  Intellectual Property Rights or other rights that might be claimed to
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Acknowledgement

  Funding for the RFC Editor function is currently provided by the
  Internet Society.







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