MD5 Algorithm

MD5 is a cryptographic hash algorithm that takes an input message of any length and produces a fixed 128-bit output, usually written as a 32-character hexadecimal string, intended originally to serve as a checksum verifying that data has not been accidentally corrupted. It processes a message in 512-bit blocks through four rounds of sixteen operations each, continually updating a 128-bit internal state held in four 32-bit words using nonlinear functions, modular addition and bit rotation, so the final state becomes the message's hash. Ronald Rivest designed MD5 in 1991 as a successor to his own earlier and weaker MD4 algorithm, and it was formally specified in April 1992 as RFC 1321. MD5 is no longer considered secure for any purpose that depends on it being infeasible to find two different inputs producing the same hash: researchers demonstrated practical collisions against it, and Carnegie Mellon's Software Engineering Institute concluded in 2008 that it was cryptographically broken and unsuitable for further use, though it remains widely deployed today for non-security checksums where that weakness does not matter.