Derive cryptographic keys from passwords using PBKDF2 with SHA-256 or SHA-512 and configurable iteration counts.
This tool derives a fixed-length cryptographic key from a password using PBKDF2, the password-based key derivation function behind most legacy password storage. You supply the password, a salt, an iteration count, and either SHA-256 or SHA-512; the tool runs the derivation in your browser and returns the derived key as hex. Nothing is uploaded. The surprise most users hit: the result is all-or-nothing. Change the salt, the iteration count, or the hash function and the output changes completely, so the same password never produces the same key twice unless every parameter matches exactly.
A concrete input and expected output from the current implementation.
Input
password: password | salt: salt | iterations: 1 | hash: SHA-256 | output length: 32 bytes
Expected output
120fb6cffcf8b32c43e7225256c4f837a86548c92ccc35480805987cb70be17b
This is the published known-answer test vector for PBKDF2-HMAC-SHA256 from RFC 7914, so any correct implementation returns exactly this hex. The 1-iteration count exists only to verify implementations; real use needs hundreds of thousands of iterations.
PBKDF2 builds the key from blocks of hLen bytes each, where hLen is the hash output length: 32 for SHA-256, 64 for SHA-512. For each block it runs HMAC keyed by the password, first on the salt plus a block index, then repeatedly on its own previous output, c times in total, and XORs the c results together. Defined in RFC 8018 section 5.2; the blocks concatenate into the final key.
The iteration count is the work factor. Every verification repeats the full HMAC chain c times, and an attacker guessing passwords pays the same cost per guess, which is the entire point. One iteration returns in microseconds; current guidance runs to hundreds of thousands. Output length multiplies cost too: each extra block is a full c-iteration pass, so request only the bytes you need.
If the stored hash is plain PBKDF2, yes, provided you have the salt and iteration count recorded alongside it, as most systems do. Enter them with the candidate password and compare the hex. But if the site mixed in an extra secret (a pepper) before deriving, or used a hash this tool does not offer (older systems used PBKDF2-HMAC-SHA1), the result will not match.
Current OWASP guidance is 600,000 iterations for PBKDF2-HMAC-SHA256, or 210,000 for SHA-512. More iterations mean safer hashes but slower logins, so choose the highest count your slowest login path tolerates. PBKDF2 uses CPU alone with little memory, so dedicated hardware attacks it efficiently; OWASP's preferred function is Argon2id, with PBKDF2 remaining the standard where FIPS compliance is required.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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