How to generate a hash
- Type text or choose a file.
- All hashes are calculated at once.
- Paste a published checksum to check that a download is intact.
Verifying downloads
Software sites publish a SHA-256 checksum next to the file. Hash your download and compare: if the values match, the file was not corrupted or tampered with on the way.
Hashes in development
Git identifies commits by hash, caches use content hashes in file names, and APIs sign requests with HMAC built on SHA-256. Deduplication compares hashes instead of whole files.
Hashing is not encryption
A hash cannot be turned back into the data. For passwords, use a dedicated slow algorithm such as Argon2, bcrypt or scrypt with a salt, never plain MD5 or SHA.
Frequently asked questions
What is a hash?
A fixed-length fingerprint of data. The same input always gives the same hash, and changing a single byte changes it completely.
Can a hash be reversed?
No. Hashes are one-way. Short or common inputs can be found in lookup tables, which is why passwords need slow, salted algorithms like bcrypt or Argon2.
Which algorithm should I use?
SHA-256 for checksums and signatures. MD5 and SHA-1 are only suitable for detecting accidental changes.
Are my files uploaded?
No. Files are read and hashed on your device.