Webmaster in a Nutshell, 3rd Edition By Robert Eckstein, Stephen Spainhour
Table of Contents
Chapter 18. Apache Configuration
ContentDigest
ContentDigest onoff
Computes an MD5 (Message Digest 5) hash of the body content of core data sent to the client. This value is stored in a header that looks like:
Content-MD5: AyTr28784eSp2k67d98n28a=
The receiver can use this hash value to determine whether the contents of the page have been altered in transit. The hash values are not cached for each page sent; hence, they must be recalculated each time data is requested .
