⌗Hash Generator

Do not use this to store passwords.

That is the one thing worth saying before anything else, because SHA is fast by design and password storage needs an algorithm that is deliberately slow. A modern GPU works through billions of SHA-256 guesses per second. Against bcrypt or Argon2, configured properly, it manages a few thousand. If you are hashing passwords for a database, you want the slow one.

For everything else — checksums, signatures, cache keys, verifying a file matches what was published — this is the right tool.

Which algorithm

SHA-256 unless something specifically asks for otherwise. SHA-384 and SHA-512 produce longer digests and are appropriate where a specification calls for them.

SHA-1 is here for exactly one reason: checking old published checksums. It is cryptographically broken, practical collisions have been demonstrated, and it should never sit anywhere that security depends on the result.

Why your checksum does not match

This hashes text, not files. If you are comparing against a file checksum it will never agree, because the file has a trailing newline or different line endings and yours does not.

The byte counter under the output is there for the other common cause. Text with accented or non-Latin characters encodes to a different number of bytes than its character count suggests, and a string encoded as UTF-8 hashes differently from the same string in another encoding. If two systems disagree about a hash, encoding is the first thing to check.

On reversing hashes

You cannot, by computation. Sites that appear to do it are looking the value up in a table of previously hashed common inputs — which is precisely why short, predictable text should never be protected by a bare hash, and why salting exists.

Everything runs through the browser Web Crypto API. Nothing is uploaded.