RFC 1864 (rfc1864) - Page 1 of 4
The Content-MD5 Header Field
Alternative Format: Original Text Document
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