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Versions: 00 01 02 03 RFC 6713

Network Working Group                                        J.R. Levine
Internet-Draft                                      Taughannock Networks
Intended status: Informational                                 June 2012
Expires: December 13, 2012

         The application/zlib and application/gzip media types
                    draft-levine-application-gzip-03

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

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 13, 2012.

Copyright Notice

   Copyright (c) 2012 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.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

1.  Introduction

   The Zlib [RFC1950] and gzip [RFC1952] formats are widely used
   compression formats.  Zlib is a stream format, while gzip adds header
   and trailer fields more appropriate for a file format.  Both
   implement the DEFLATE compression scheme described in [RFC1951].


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

   Some applications have informally used media types including
   application/gzip-compressed, application/gzipped, application/
   x-gunzip, application/x-gzip, application/x-gzip-compressed, and gzip
   /document to describe data compressed with gzip.  The media types
   defined in this document should replace those media types 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.  Registration Details

   Type name: application

   Subtype name: zlib

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: Binary.

   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. The first two bytes when
      interpreted as an unsigned 16-bit number in big-endian byte order
      contain a value that is a multiple of 31.
      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

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3.  The Application/Gzip Media Type

   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.  Registration Details

   Type name: application

   Subtype name: gzip

   Required parameters: N/A

   Optional parameters: N/A

   Encoding considerations: Binary.

   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.org/

   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 skepticism.

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


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5.  IANA Considerations

   IANA is requested to update the MIME Media Types registry to include
   application/zlib as described in Section [zlib] and application/gzip
   as described in Section [gzip].

6.  References

   [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 -02 to -03

   Add IANA considerations

   Simplify encoding: binary and fix typos

Appendix A.2.  Changes from -01 to -02

   Fix gzip.org

   Note other former names

Appendix A.3.  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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