Hashing

A one-way mathematical process that converts data into a fixed-length string of characters, used to verify integrity and store passwords without keeping the actual password.

A hash function takes any input, such as a password or a file, and produces a short, unique-looking output called a hash. The same input always gives the same hash, but even a tiny change produces a completely different result. Unlike encryption, hashing is designed not to be reversed. Well-designed systems store password hashes rather than the passwords themselves.

Hashing matters to businesses in a few practical ways. If a website or application stores passwords using strong, modern hashing methods, a breach of that database is less damaging. If it stores them in plain text or with weak hashing, attackers can quickly recover the passwords and try them elsewhere. Hashes are also used to confirm a downloaded file has not been tampered with and to identify known malware.

Practical tip: when choosing business software or hiring a developer for a custom application, ask how user passwords are stored. The answer should involve a modern, purpose-built password hashing method, never plain text or simple reversible encryption.