What is Hash function?
Hash function Definition: Accepts an input message of any length and generates, through a one-way operation, a fixed-length output called a message digest or hash.
Understanding Hash function
Accepts an input message of any length and generates, through a one-way operation, a fixed-length output called a message digest or hash. A hash function is a cryptographic algorithm that transforms data of arbitrary size into a fixed-size string hash value or digest. Key properties include one-way operation impossible to reverse, determinism same input always produces same output, and collision resistance difficult to find different inputs with same output. Hash function standards include SHA-2, SHA-3, specified in FIPS 180-4 and FIPS 202. Organizations implement hashing for data integrity verification, password storage, digital signatures, and data deduplication. For example, a secure application might store passwords as salted SHA-256 hashes rather than plaintext, allowing password verification without ever storing the actual password. Related terms: Cryptographic hash, Message digest, SHA-256, MD5, Collision, One-way function, Digital signature, Password hashing.