Hash Format Identifier
Read password-hash prefixes and find algorithms that match the output length
Formats such as bcrypt and Argon2 include a prefix, settings and salt. This tool reads those fields, along with common scrypt, PBKDF2, Unix crypt, LDAP and database hash formats. To check a password against the hash, use its verification tool.
A 32-character hex value is 128 bits and could be MD5, MD4, NTLM, or arbitrary bytes. A 64-character hex value is 256 bits and could fit SHA-256, SHA3-256, Keccak-256, BLAKE2s, a key, or another identifier. Length narrows the possibilities, but it does not identify the algorithm.
A recognized format has an identifying prefix and readable fields. A suggested format fits the characters and length. Check the application or database that stored the hash to confirm which algorithm it uses.
Hashing is one-way: the original password cannot be recovered from the hash. To check a password you already have, choose the matching verification tool. Use your application's documented algorithm and settings when a value has no identifying prefix.
- String Format Identifier Start here when the value may not be a hash at all.
- Verify Bcrypt Compare plaintext with a confirmed bcrypt hash.
- Verify Argon2id Verify a confirmed Argon2id PHC string.
- File Checksum Calculate SHA-256 for a local file and compare it with a published digest.
- SHA-256 Hash Tool Generate a known SHA-256 digest from text.
- SHA-256 vs MD5 vs bcrypt guide Choose between file checksums and password hashing.
Can a hash be decoded back to its original value?
No. Hash functions are one-way. Verification hashes a candidate under the same rules and compares the result.
Does 32 hex characters always mean MD5?
No. It is an MD5-sized value, but MD4, NTLM, random bytes, keys, and identifiers can have the same length.
How do I check a password against bcrypt or Argon2?
Open the matching verification tool and enter the hash and the password you want to check.