RFC 1864 (rfc1864) - Page 1 of 4

The Content-MD5 Header Field

Alternative Format: Original Text Document
Next >
Network Working Group                                           J. Myers
Request For Comments: 1864                               Carnegie Mellon
Obsoletes: 1544                                                  M. Rose
                                            Dover Beach Consulting, Inc.
                                                            October 1995


                      The Content-MD5 Header Field

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.

Abstract

   This memo specifies an optional header field, Content-MD5, for use
   with MIME-conformant messages.

Table of Contents

   1. Introduction ..............................................    1
   2. Generation of the Content-MD5 Field .......................    2
   3. Processing the Content-MD5 field ..........................    3
   4. Security Considerations ...................................    3
   5. Acknowledgements ..........................................    3
   6. References ................................................    3
   7. Authors' Addresses ........................................    4

1. Introduction

   Despite all of the mechanisms provided by MIME [1] which attempt to
   protect data from being damaged in the course of email transport, it
   is still desirable to have a mechanism for verifying that the data,
   once decoded, are intact.  For this reason, this memo defines the use
   of an optional header field, Content-MD5, which may be used as a
   message integrity check (MIC), to verify that the decoded data are
   the same data that were initially sent.  The Content-MD5 header may
   also be placed in the encapsulated headers of an object of type
   message/external-body, to be used to verify that the retreived and
   decoded data are the same data that were initially referenced.

   MD5 is an algorithm for computing a 128 bit "digest" of arbitrary-
   length data, with a high degree of confidence that any alterations in
   the data will be reflected in alterations in the digest.  The MD5



Myers & Rose                Standards Track
Next >