What is MD5?

MD5 (Message-Digest Algorithm 5) is a widely used cryptographic hash function that produces a 128-bit (16-byte) hash value, typically expressed as a 32-character hexadecimal number. Designed by Ronald Rivest in 1991, MD5 was commonly used for checksums and file integrity verification. However, MD5 is now considered cryptographically broken—collision attacks have been demonstrated, meaning two different inputs can produce the same hash. Do not use MD5 for passwords or security-sensitive applications. It remains useful for non-security purposes such as checksums and cache keys.