Apache Reference: http_core, ContentDigest

ContentDigest

Generation of Content-MD5 headers
Syntax: ContentDigest on|off
Example: ContentDigest on
Since: Apache 1.1

This directive enables the generation of Content-MD5 headers as defined in RFC 1864 and RFC 2068, respectively. MD5 is an algorithm for computing a ``message digest'' (also known as a ``fingerprint'') of arbitrary-length data, with a high degree of confidence that any changes in the data will be reflected as changes in the message digest. The Content-MD5 header provides an end-to-end message integrity check of the HTTP response body. A proxy or client may check this header in an effort to detect accidental modification of the contents in transit.