One document matched: draft-ietf-ediint-compression-01.txt

Differences from draft-ietf-ediint-compression-00.txt

Internet Draft                                     Editor: Terry Harding
draft-ietf-ediint-compression-01.txt               Cyclone Commerce Inc.
Feburary 2003
Expires August 2003
Target Category: Informational           

                  Compressed Data for EDIINT

Status of this memo

This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.

Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups.  Note that other
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The list of current Internet-Drafts can be accessed at
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Copyright (C) The Internet Society July 2001.  All Rights Reserved.

Abstract

The intent of this document is to be placed on the RFC track as an 
Informational RFC.

The EDIINT AS1 and AS2 message formats don't currently contain any 
transport neutral provisions for compressing data when utilizing S/MIME
as the secure packaging standard. Compressing data before transmission 
provides a number of advantages including

1. reducing data redundancy, and so reducing opportunities for attacks
exploiting redundancy, and
2. reducing the amount of data and so speeding up cryptographic
processing such as signing, encryption, archiving, and 
3. reducing the overall transmitted message size, reducing both time and
bandwidth needed for transport.


1. Introduction


Terry Harding                                                [Page 1]
Compressed Data for EDIINT                             November, 2001

This document describes an additional mime layer of compressed data 
utilizing a new ContentInfo type for S/MIME. This new compressed-data 
content type is an extension to the types currently defined in 
CMS[RFC2630]. Further reference can be found in the reference section 
under [COMPRESSED-DATA]. The method of compression outlined in this 
document will support any type of business related media. Documents 
containing a large percentage of ASCII characters like xml, x12 or 
edifact will experience greater compression ratios than documents 
consisting largely of binary data. Ex: MSWord documents.
 

The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
"RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be
interpreted as described in [RFC2119].

1.1 Compressed-Data Mime Wrapper

The compressed-data cms object will encapsulate a mime wrapped business
document. Implementors are to follow the appropriate specifications
identified under "References" in [MIME-TYPES], for the type of object
being transmitted. For example, to send an XML object, the MIME media
type of application/xml is used in the Content-type MIME header and the
specifications for enveloping the object are contained in [XMLTYPES]; 
for example:

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

The mime wrapped object will be compressed and placed inside a CMS 
compressed-data object as outlined in [COMPRESSED-DATA]. The compressed
data object will be mime wrapped according to details outlined in
[S/MIME],Section 3.2. Since RFC2633 does not specifically reference the
new compressed-data type, we will use the encrypted-only section 3.3 as 
a guide to properly mime wrapping the compressed data object.

Example:

	Content-type: application/pkcs7-mime; smime-type=compressed-data;
            name=smime.p7m
        Content-Transfer-Encoding: base64
        Content-Disposition: attachment; filename=smime.p7m

        rfvbnj756tbBghyHhHUujhJhjH77n8HHGT9HG4VQpfyF467GhIGfHfYT6
        7n8HHGghyHhHUujhJh4VQpfyF467GhIGfHfYGTrfvbnjT6jH7756tbB9H
        f8HHGTrfvhJhjH776tbB9HG4VQbnj7567GhIGfHfYT6ghyHhHUujpfyF4
        0GhIGfHfQbnj756YT64V

Note: Content-Transfer-Encoding would only be required if the mime 
wrapped CMS object was transferred via SMTP and it was visible in the 
outer layer of the mime message. If the compressed-data mime bodypart 
was place inside of an encrypted mime bodypart, 

Terry Harding                                                [Page 2]
Compressed Data for EDIINT                             November, 2001

content-transfer-encoding would not be required on the compressed-data 
mime bodypart, but would be required on the encrypted mime bodypart.

1.2 Structure of an EDI MIME message utilizing compression

1.2.1 No encryption, no signature

   -RFC822/2045
     -[COMPRESSED-DATA](application/pkcs7-mime)
       -[MIME-TYPES](application/xxxxxxx)

1.2.2 No encryption, signature

   -RFC822/2045
     -RFC1847 (multipart/signed)
       -[COMPRESSED-DATA](application/pkcs7-mime)
         -[MIME-TYPES](application/xxxxxxx)
       -RFC2633 (application/pkcs7-signature)

1.2.3 Encryption, no signature

   -RFC822/2045
     -RFC2633 (application/pkcs7-mime)
       -[COMPRESSED-DATA](application/pkcs7-mime) (encrypted)
         -[MIME-TYPES](application/xxxxxxx) (encrypted)

1.2.4 Encryption, signature

   -RFC822/2045
     -RFC2633 (application/pkcs7-mime)
       -RFC1847 (multipart/signed) (encrypted)
         -[COMPRESSED-DATA](application/pkcs7-mime) (encrypted)
           -[MIME-TYPES](application/xxxxxxx) (encrypted)
         -RFC2633 (application/pkcs7-signature) (encrypted)


2. MIC Calculations For Signed Receipts

   For signed compressed messages, the MIC to be returned 
   is calculated over the entire compressed data mime bodypart, 
   including all RFC 822 headers and any Content-Transfer-Encoding 
   that was applied to the compressed data.

   For encrypted, unsigned compressed messages, the MIC to be returned
   is calculated over the entire compressed data mime bodypart, 
   including all RFC 822 headers and any Content-Transfer-Encoding 
   that was applied to the compressed data.

   For unsigned, unencrypted compressed messages, the MIC MUST be 
   calculated over the compressed message contents prior to 

Terry Harding                                                [Page 3]
Compressed Data for EDIINT                             November, 2001

   Content-Transfer-Encoding and without the MIME or any other 
   RFC 822 headers.


3. Compression Formats

Implementations SHOULD support ZLIB [RFC1950] which utilizes 
DEFLATE[RFC1951], and is free of any intellectual property 
restrictions and has a freely-available, portable and efficient 
reference implementation.


4. Security Considerations

This document is not concerned with security, except for the fact that
compressing data before encryption can enhance the security by reducing
redundancy of the file. The lower the redundancy of the plaintext being 
encrypted, the more difficult the cryptanalysis, see 
reference[CRYPTANALYSIS]. 


Author Address

Terry Harding
Cyclone Commerce Inc.
Scottsdale, Arizona, USA
tharding@cyclonecommerce.com

References

  [RFC2119] Key Words for Use in RFC's to Indicate Requirement Levels,
        S.Bradner, March 1997.

  [ZLIB] RFC1950 ZLIB Compressed Data Format Specification version 3.3,
        P.Deutsch and J-L Gailly, May 1996.

  [DEFLATE] RFC1951 DEFLATE Compressed Data Format Specification version
            1.3, P.Deutsch, May 1996.

  [CMS] RFC2630 Cryptographic Message Syntax, R.Housley, June 1999.

  [S/MIME]RFC2633 S/MIME Version 3 Message Specification, B.Ramsdell,
          June 1999.

  [MIME-TYPES]  "Media Types," http://www.isi.edu/in-
                notes/iana/assignments/media-types/media-types.

  [XMLTYPES]  E. Whitehead, M. Murata, "XML Media Types", RFC 2376,
              July 1998.


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Compressed Data for EDIINT                             November, 2001

  [COMPRESSED-DATA]  P. Gutmann, "Compressed Data Content Type for CMS" 
                     draft-ietf-smime-compression-05.txt, July 2001.

  [CRYPTANALYSIS]  B. Schneier, "Self-Study Course in Block Cipher
 Cryptanalysis", http://www.counterpane.com/self-study.html, Jan 2000.

Acknowledgements

   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 Fisher, Dale Moberg, Robert Asis. 


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Terry Harding                                                [Page 5]