Hashing is the process of converting input data into a fixed-size output using a mathematical hash function. Hashes are deterministic, fast to compute, and designed so that small changes in input produce large changes in output. Hashing is used for indexing, checksums, caching, and security applications like password storage. Unlike encryption, hashing is one-way and cannot be reversed.
Why it matters
Hashes ensure data integrity, enable fast lookups, and secure sensitive information. In authentication systems, passwords are stored using secure hash algorithms combined with salts. Hashing is also fundamental to database indexing, distributed systems, and caching.
Examples
SHA-256 is widely used for digital signatures and integrity checks. Lessons like SHA and Password Hashing explain hashing in security contexts.