This whitepaper discusses a methodology for using MD5 checksums to verify that content on a website has not been manipulated.
You can download it from the following link: https://packetstormsecurity.com/files/download/81367/antibot-md5.txt
Source: https://packetstormsecurity.com/files/81367/Anti-Defacement-MD5-Checksum-Whitepaper.html