What is hashing and how does it differ from encryption?

Hashing is a one-way mathematical function that converts input of any size into a fixed-length output called a digest or hash value. Unlike encryption, hashing is irreversible and you cannot recover the original data from the hash. Hashing verifies integrity: if the data changes, the hash changes. Common algorithms include SHA-256 producing a 256-bit digest and SHA-3. MD5 and SHA-1 are deprecated due to collision vulnerabilities. Hashing is used for password storage, digital signatures, file integrity verification, and blockchain.