File verification
File verification is the field of computer science in which an algorithm is used to verify the integrity or authenticity of a file.
Integrity
File intergrity can be compromised, usually refered to as the file becoming corrupted. A file can become corrupted by a variety of ways: faulty storage media, errors in transmission, write errors during copying or moving, and so on. File verification formats allows a person to ensure that a file has not become corrupted by comparing a hash applied a file to see that they are equal.
Authenticity
File verification formats also users to verify the authenticity of files, since if a file was changed (say, with the addition of mallicious code) the hash 'fingerprint' of the file would change and alter the user that the authenticity of the file is in question. Many files released have a check file that allows users to verify the file.
Formats
Message Digest
Insecure Formats