Independent Submission                                   T. Harding, Ed.
Request for Comments: 5402                                         Axway
Category: Informational                                    February 2010
ISSN: 2070-1721


                   Compressed Data within an Internet
               Electronic Data Interchange (EDI) Message

Abstract

   This document explains the rules and procedures for utilizing
   compression (RFC 3274) within an Internet EDI (Electronic Data
   Interchange) 'AS' message, as defined in RFCs 3335, 4130, and 4823.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5402.

IESG Note

   The content of this RFC was at one time considered by the IETF, and
   therefore it may resemble a current IETF work in progress or a
   published IETF work.  This RFC is not a candidate for any level of
   Internet Standard.  Readers of this RFC should exercise caution in
   evaluating its value for implementation and deployment.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http:trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

   carefully, as they describe your rights and restrictions with respect
   to this document.

1.  Introduction

   Historically, electronic messages produced by systems following the
   guidelines as outlined in the IETF EDIINT Working Group
   specifications AS1 [AS1], AS2 [AS2], and AS3 [AS3] did not have a way
   to provide a standardized transport neutral mechanism for compressing
   large payloads.  However, with the development of RFC 3274,
   "Compressed Data Content Type for Cryptographic Message Syntax
   (CMS)", we now have a transport-neutral mechanism for compressing
   large payloads.

   A typical EDIINT 'AS' message is a multi-layered MIME message,
   consisting of one or more of the following: payload layer, signature
   layer, and/or encryption layer.  When an 'AS' message is received, a
   Message Integrity Check (MIC) value must be computed based upon
   defined rules within the EDIINT 'AS' RFCs and must be returned to the
   sender of the message via a Message Disposition Notification (MDN).

   The addition of a new compression layer will require this document to
   outline new procedures for building/layering 'AS' messages and
   computing a MIC value that is returned in the MDN receipt.

   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 [RFC2119].

2.  Compressed Data MIME Layer

   The compressed-data CMS (Cryptographic Message Syntax) MIME entity as
   described in [COMPRESSED-DATA] may encapsulate a MIME entity that
   consists of either an unsigned or signed business document.

   Implementers are to follow the appropriate specifications identified
   in the "MIME Media Types" registry [MIME-TYPES] maintained by IANA
   for the type of object being packaged.  For example, to package an
   XML object, the MIME media type of "application/xml" is used in the
   Content-Type MIME header field and the specifications for enveloping
   the object are contained in [XMLTYPES].

   MIME entity example:

   Content-type: application/xml; charset="utf-8"

   <?xml version="1.0" encoding="UTF-8"?>
   <!-- sample xml document -->

   The MIME entity will be compressed using [ZLIB] and placed inside a
   CMS compressed-data object as outlined in [COMPRESSED-DATA].  The
   compressed-data object will be MIME encapsulated according to details
   outlined in [S/MIME3.1], RFC 3851, Section 3.5.

   Example:

   Content-Type: application/pkcs7-mime; smime-type=compressed-data;
   name=smime.p7z
   Content-Transfer-Encoding: base64
   Content-Disposition: attachment; filename=smime.p7z

   MIAGCyqGSIb3DQEJEAEJoIAwgAIBADANBgsqhkiG9w0BCRADCDCABgkqhkiG9w0BBwGg
   Hnic7ZRdb9owFIbvK/k/5PqVYPFXGK12YYyboVFASSp1vQtZGiLRACZE49/XHoUW7S/0
   fU5ivWnasml72XFb3gb5druui7ytN803M570nii7C5r8tfwR281hy/p/KSM3+jzH5s3+
   P3VT3QbLusnt8WPIuN5vN/vaA2+DulnXTXkXvNTr8j8ouZmkCmGI/UW+ZS/C8zP0bz2d
   UEk2M8mlaxjRMByAhZTj0RGYg4TvogiRASROsZgjpVcJCb1KV6QzQeDJ1XkoQ5Jm+C5P
   v+ORAcshOGeCcdFJyfgFxdtCdEcmOrbinc/+BBMzRThEYpwl+jEBpciSGWQkI0TSlREm
   SGLuESm/iKUFt1y4XHBO2a5oq0IKJKWLS9kUZTA7vC5LSxYmgVL46SIWxIfWBQd6Adrn
   vGxVibLqRCtIpp4g2qpdtqK1LiOeolpVK5wVQ5P7+QjZAlrh0cePYTx/gNZuB9Vhndtg
   W9ogK+3rnmg3YWygnTuF5GDS+Q/jIVLnCcYZFc6Kk/+c80wKwZjwdZIqDYWRH68MuBQS
   3CAaYOBNJMliTl0X7eV5DnoKIFSKYdj3cRpD/cK/JWTHJRe76MUXnfBW8m7Hd5zhQ4ri
   +kV1/3AGSlJ32bFPd2BsQD8uSzIx6lObkjdz95c0AAAAAAAAAAAAAAAA

   Note: Content-Transfer-Encoding of base64 would only be required if
   the compressed-data MIME bodypart is transferred via a 7-bit protocol
   like SMTP and is visible in the outer layer of the MIME message.  If
   the compressed-data MIME bodypart is placed inside of an encrypted
   MIME bodypart, content-transfer-encoding would not be required on the
   compressed-data MIME bodypart, but would be required on the encrypted
   MIME bodypart.

3.  Structure of an EDI MIME Compressed Message

   When compressing a document that will be signed, the application MAY
   compress the innermost MIME body before signing (see Sections 3.2 and
   3.5), or it MAY compress the outer multipart/signed MIME body (see
   Sections 3.3 and 3.6), but it MUST NOT do both within the same
   document.  The receiving application MUST support both methods of
   compression when unpackaging an inbound document.

   Note: The following sections (3.1 - 3.6) show the individual layers
   of a properly formatted EDI MIME message with a compressed data
   layer.  Please refer to the appropriate RFCs for the proper
   construction of the resulting MIME message.  "application/xxxxxxx" is
   used to indicate an application media subtype.

3.1.  No Encryption, No Signature

   -RFC5322/2045
     -[COMPRESSED-DATA](application/pkcs7-mime)
       -[MIME-TYPES](application/xxxxxxx)(compressed)

   This section shows the layers of an unsigned, unencrypted compressed
   message.  The first line indicates that the MIME message conforms to
   [RFC5322] and [RFC2045] with a Content-Type of
   application/pkcs7-mime.  Within the pkcs7-mime entity is a compressed
   MIME entity containing the electronic business document.

3.2.  No Encryption, Signature

   -RFC5322/2045
     -[RFC1847] (multipart/signed)
       -[COMPRESSED-DATA](application/pkcs7-mime)
         -[MIME-TYPES](application/xxxxxxx)(compressed)
       -RFC3851 (application/pkcs7-signature)

   This section shows the layers of a signed, unencrypted compressed
   message where the payload is compressed before being signed.

3.3.  No Encryption, Signature

   -RFC5322/2045
     -[COMPRESSED-DATA](application/pkcs7-mime)
       -[RFC1847] (multipart/signed)(compressed)
         -[MIME-TYPES](application/xxxxxxx)(compressed)
         -RFC3851 (application/pkcs7-signature)(compressed)

   This section shows the layers of a signed, unencrypted compressed
   message where a signed payload is compressed.

3.4.  Encryption, No Signature

   -RFC5322/2045
     -RFC3851 (application/pkcs7-mime)
       -[COMPRESSED-DATA](application/pkcs7-mime) (encrypted)
         -[MIME-TYPES](application/xxxxxxx)(compressed)(encrypted)

   This section shows the layers of an unsigned, encrypted compressed
   message where the payload is compressed before it is encrypted.

3.5.  Encryption, Signature

   -RFC5322/2045
     -RFC3851 (application/pkcs7-mime)
       -[RFC1847] (multipart/signed) (encrypted)
         -[COMPRESSED-DATA](application/pkcs7-mime) (encrypted)
           -[MIME-TYPES](application/xxxxxxx) (compressed)(encrypted)
         -RFC3851 (application/pkcs7-signature) (encrypted)

   This section shows the layers of a signed, encrypted compressed
   message where the payload is compressed before being signed and
   encrypted.

3.6.  Encryption, Signature

   -RFC5322/2045
     -RFC3851 (application/pkcs7-mime)
       -[COMPRESSED-DATA](application/pkcs7-mime) (encrypted)
         -[RFC1847] (multipart/signed) (compressed)(encrypted)
           -[MIME-TYPES](application/xxxxxxx) (compressed)(encrypted)
           -RFC3851 (application/pkcs7-signature)(compressed)(encrypted)

   This section shows the layers of a signed, encrypted compressed
   message where the payload is signed before being compressed and
   encrypted.

4.  MIC Calculations for Compressed Messages Requesting Signed Receipts

4.1.  MIC Calculation for Signed Message

   For any signed message, the MIC to be returned is calculated over the
   same data that was signed in the original message as per [AS1].  The
   signed content will be a MIME bodypart that contains either
   compressed or uncompressed data.

4.2.  MIC Calculation for Encrypted, Unsigned Message

   For encrypted, unsigned messages, the MIC to be returned is
   calculated over the uncompressed data content including all MIME
   header fields and any applied Content-Transfer-Encoding.

4.3.  MIC Calculation for Unencrypted, Unsigned Message

   For unsigned, unencrypted messages, the MIC is calculated over the
   uncompressed data content including all MIME header fields and any
   applied Content-Transfer-Encoding.

5.  Error Disposition Modifier

   For a received message where a receipt has been requested and
   decompression fails, the following disposition modifier will be
   returned in the signed MDN.

   "Error: decompression-failed" - the receiver could not decompress
                                   the message

6.  EDIINT Version Header Field

   Any application that supports the compression methods outlined within
   this document MUST use a version identifier value of "1.1" or greater
   within the AS2 or AS3 Version header field as describe in [AS2] and
   [AS3].

7.  Compression Formats

   Implementations MUST support ZLIB [ZLIB], which utilizes DEFLATE
   [DEFLATE].

8.  Security Considerations

   This document is not concerned with security, except for any security
   concerns mentioned in the referenced RFCs.

9.  Normative References

   [AS1]         Harding, T., Drummond, R., and C. Shih, "MIME-based
                 Secure Peer-to-Peer Business Data Interchange over the
                 Internet", RFC 3335, September 2002.

   [AS2]         Moberg, D. and R. Drummond, "MIME-Based Secure Peer-to-
                 Peer Business Data Interchange Using HTTP,
                 Applicability Statement 2 (AS2)", RFC 4130, July 2005.

   [AS3]         Harding, T. and R. Scott, "FTP Transport for Secure
                 Peer-to-Peer Business Data Interchange over the
                 Internet", RFC 4823, April 2007.

   [ZLIB]        Deutsch, P. and J-L. Gailly, "ZLIB Compressed Data
                 Format Specification version 3.3", RFC 1950, May 1996.

   [DEFLATE]     Deutsch, P., "DEFLATE Compressed Data Format
                 Specification version 1.3", RFC 1951, May 1996.

   [MIME-TYPES]  IANA, "MIME Media Types" registry, available from
                 http://www.iana.org.

   [RFC1847]     Galvin, J., Murphy, S., Crocker, S., and N. Freed,
                 "Security Multiparts for MIME: Multipart/Signed and
                 Multipart/Encrypted", RFC 1847, October 1995.

   [RFC2045]     Freed, N. and N. Borenstein, "Multipurpose Internet
                 Mail Extensions (MIME) Part One: Format of Internet
                 Message Bodies", RFC 2045, November 1996.

   [RFC2119]     Bradner, S., "Key words for use in RFCs to Indicate
                 Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5322]     Resnick, P., Ed., "Internet Message Format", RFC 5322,
                 October 2008.

   [S/MIME3.1]   Ramsdell, B. and S. Turner, "Secure/Multipurpose
                 Internet Mail Extensions (S/MIME) Version 3.2 Message
                 Specification", RFC 5751, January 2010.

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

   [COMPRESSED-DATA]
                 Gutmann, P., "Compressed Data Content Type for
                 Cryptographic Message Syntax (CMS)", RFC 3274, June
                 2002.

10.  Acknowledgments

   A number of the members of the EDIINT Working Group have also worked
   very hard and contributed to this document. The following people have
   made direct contributions to this document:

   David Fischer, Dale Moberg, Robert Asis, and everyone involved in the
   AS1, AS2 Interop testing during 2002.

Author's Address

   Terry Harding
   Axway
   Scottsdale, Arizona
   USA

   EMail: tharding@us.axway.com