A hash function is a cryptographic one-way function that generates a fixed-size output (hash value, digest) from arbitrary-size input data. The same input always produces the same hash, but even a slight change in input produces a completely different hash. This property makes it ideal for data verification and integrity checking.
Supported Hash Algorithms
This tool supports major hash algorithms: MD5 (128-bit, legacy), SHA-1 (160-bit, legacy), SHA-256 (256-bit, recommended), SHA-384 (384-bit), and SHA-512 (512-bit, maximum security). SHA-256 or higher is recommended for security-critical applications. MD5 and SHA-1 have known vulnerabilities and should be avoided except for maintaining compatibility.
Security Properties
Cryptographic hash functions have three important properties: (1) One-way: computationally infeasible to recover original data from hash. (2) Collision resistance: extremely difficult for two different inputs to produce the same hash. (3) Avalanche effect: slight input change causes massive hash change. These properties make them ideal for data verification, digital signatures, and password storage.
Importance of One-Way Functions
Hash functions are one-way, meaning you cannot recover the original data from the hash value. This property makes them ideal for password storage, data verification, and creating digital fingerprints of files. If passwords are hashed and stored, the passwords themselves remain protected even if the database is compromised.