The application/zlib and application/gzip media types
draft-levine-application-gzip-01

Network Working Group                                        J.R. Levine
Internet-Draft                                      Taughannock Networks
Intended status: Informational                                March 2012
Expires: September 12, 2012

         The application/zlib and application/gzip media types
                    draft-levine-application-gzip-01

Abstract

   This document defines the 'application/gzip' and 'application/zlib'
   media types for compressed data using the gzip and zlib compression
   formats.

Status of this Memo

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   This Internet-Draft will expire on September 12, 2012.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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1.  Introduction

   The Zlib [RFC1950] and gzip [RFC1952] formats are widely used
   compression formats.  Zlib is a stream format, while glib adds header
   and trailer fields more appropriate for a file format.  Both

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   implement the DEFLATE compression scheme described in [RFC1951].

   They are used to compress a wide variety of material, from
   unstructured text to structured data to executable code.

   Some applications have informally used the media type application/
   x-gzip.  The media types defined in this document should replace that
   media type in future applications.

2.  The Application/Zlib Media Type

   The application/zlib media type describes a block of data that is
   compressed using Zlib [RFC1950] compression.  The data is a stream of
   bytes as described in RFC 1950.

2.1.  Regsistration Details

   Type name: application

   Subtype name: zlib

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: needs base64 or other encoding that allows
   arbitrary binary data

   Security considerations: See section [security] below

   Interoperability considerations: N/A

   Published specification: [RFC1950]

   Applications that use this media type: anywhere data size is an issue

   Additional information:

      Magic number(s): first byte is usually 0x78 but can also be 0x08,
      0x18, 0x28, 0x38, 0x48, 0x58, or 0x68.
      File extension(s): N/A
      Macintosh file type code(s): N/A

   Person and email address to contact for further information: see
   http://www.zlib.net/

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: John Levine

   Change controller: IETF

3.  The Application/Gzip Media Type

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   The application/gzip media type describes a block of data that is
   compressed using gzip [RFC1952] compression.  The data is a stream of
   bytes as described in RFC 1952.

3.1.  Regsistration Details

   Type name: application

   Subtype name: gzip

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: needs base64 or other encoding that allows
   arbitrary binary data

   Security considerations: See section [security] below

   Interoperability considerations: N/A

   Published specification: [RFC1952]

   Applications that use this media type: anywhere data size is an issue

   Additional information:

      Magic number(s): first two bytes are 0x1f, 0x8b.
      File extension(s): gz
      Macintosh file type code(s): N/A

   Person and email address to contact for further information: see
   http://www.gzip.net/

   Intended usage: COMMON

   Restrictions on usage: N/A

   Author: John Levine

   Change controller: IETF

4.  Security Considerations

   Zlib and gzip compression can be used to compress arbitrary binary
   data such as hostile executable code.  Also, data that purports to be
   in zlib or gzip format may not be, and fields that are supposed to be
   flags, lengths, or pointers, could contain anything.  Applications
   should treat any data with due scepticism.

   Also see the security considerations in the underlying format
   documents, Section 5 of [RFC1950], Section 6 of [RFC1951], and
   Section 4 of [RFC1952].

5.  References

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   [RFC1950]  Deutsch, L.P. and J-L. Gailly, "ZLIB Compressed Data
              Format Specification version 3.3", RFC 1950, May 1996.

   [RFC1951]  Deutsch, P., "DEFLATE Compressed Data Format Specification
              version 1.3", RFC 1951, May 1996.

   [RFC1952]  Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L.P. and G.
              Randers-Pehrson, "GZIP file format specification version
              4.3", RFC 1952, May 1996.

Appendix A.  Change log

   Note to editor: Please remove this section before publication.

Appendix A.1.  Changes from -00 to -01

   Note former x-gzip

   Refer to security sections in underlying format docs

Author's Address

   John Levine
   Taughannock Networks
   PO Box 727
   Trumansburg, NY 14886
   
   Phone: +1 831 480 2300
   Email: standards@taugh.com

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