A hash function takes any input — a word, a file, a password — and produces a fixed-length string that acts as its fingerprint. Change the input by a single character and the hash changes completely.
What hashing is for
- Integrity: publish a file's hash so others can confirm their download wasn't corrupted or tampered with.
- Comparison: check whether two inputs are identical without revealing them.
- Storage: systems store the hash of a password, not the password itself.
Generate SHA-1, SHA-256 and SHA-512 with the Hash Generator.
Hashing is one-way
You cannot turn a hash back into the original — that's the whole point, and it's what separates hashing from encoding (reversible) and encryption (reversible with a key). A hash only ever goes forward.
Which algorithm?
- SHA-256 is the sensible default for integrity and general use.
- SHA-512 is fine where you want a longer digest.
- SHA-1 is included for compatibility but is considered weak — don't use it for anything security-critical.
Because it runs in your browser via the Web Crypto API, whatever you hash never leaves your device.