Hash Generator

What a hash is

A hash function turns any input into a fixed-length string. The same input always gives the same output, but even a one-letter change produces a completely different result, and you cannot work backwards from the hash to the original.

Common algorithms

• MD5 (32 hex characters) and SHA-1 (40) are broken for security use because collisions can be created. They are still handy for checking that a download was not corrupted.
• SHA-256 (64 hex characters) is the usual choice for integrity checks and digital signatures.

Not for storing passwords

Plain fast hashes are the wrong tool for passwords. Systems should use a slow, salted algorithm such as bcrypt, scrypt or Argon2. Fast hashes can be guessed billions of times per second.

Typical uses

• Comparing a file checksum with the one published by the software author.
• Detecting duplicate files.
• Creating cache keys.

Frequently asked questions

Is hashing the same as encryption?

No. Encryption can be reversed with a key. A hash is one-way by design.