MD5, SHA-1, SHA-256, SHA-512 hashes of a text or file, plus a UUID generator.
A hash is a string of characters calculated from some content. The same content always gives the same hash; the slightest change, even a single letter, gives a completely different one. It is impossible, however, to get the content back from the hash.
Many software publishers list the SHA-256 hash of their files. Drop the downloaded file and paste the published hash into the comparison field: if they match, the file is intact and was not altered on the way.
| Algorithm | Length | Use |
|---|---|---|
| MD5 | 32 characters | Quick integrity check, avoid for security |
| SHA-1 | 40 characters | Old, not recommended for security |
| SHA-256 | 64 characters | Today's standard: verification, signatures |
| SHA-512 | 128 characters | Maximum security margin |
To store passwords, none of these algorithms is enough on its own: you need dedicated, deliberately slow functions such as bcrypt or Argon2.
A UUID is a unique 128-bit identifier, for example 3f2a9c1e-7b4d-4e8a-9f21-0c5d8e6b1a47. Version 4, generated here from cryptographic randomness, is used to name records, files or orders with no risk of duplicates.
No. Hashes are calculated by your browser; nothing leaves your device.
No, a hash is one-way. Only very short or very common texts can be guessed by testing word lists: that is why MD5 is not used to protect passwords.
In theory yes, in practice no: you would need to generate billions per second for decades to have any chance of a duplicate.