Hash Generator
| Algorithm | Hash |
|---|
Compare with a published checksum
What a hash tells you
A hash is a fixed-length fingerprint of some data. Change one byte and the fingerprint changes entirely, which is what makes it useful for checking that a download, a backup or a copied file is byte-for-byte what it should be.
Choosing an algorithm
- SHA-256 — the sensible default for checksums and signatures.
- SHA-512 — longer, and faster than SHA-256 on 64-bit machines.
- SHA-1 — for verifying older published checksums only. It is broken for security use.
A note on passwords
None of these should be used to store passwords. They are built to be fast, which helps an attacker far more than it helps you. Password storage needs a slow, salted algorithm such as bcrypt, scrypt or Argon2.
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Free to use, no sign-up, works on any phone.
Frequently Asked Questions
It proves a download arrived intact and unaltered. The publisher lists a hash; you hash the file you received and compare. If a single byte differs the hash changes completely.
Because it is broken for anything security-related — two different files can be made to share an MD5, and it has been demonstrated in practice. The browser's crypto library deliberately does not include it, and adding it back would be doing you no favours.
SHA-256 for almost everything. SHA-1 is here only because older projects still publish SHA-1 checksums; do not use it for anything new, as it is no longer collision-resistant.
No. Hashing uses the browser's built-in crypto engine and reads the file locally, so a confidential document can be checked without it leaving your machine.
No. Hashing is one-way by design. A short common password could be found in a lookup table, which is precisely why passwords need salting and a slow algorithm rather than a plain hash.
The file is read in one pass, so the practical limit is your device's memory — a few hundred megabytes is usually fine on a laptop, less on a phone.