PBKDF2 Key Generator

About PBKDF2 key generator

PBKDF2 stretches a password into a fixed-length key by running an HMAC many thousands of times over the password and a salt. This tool exposes every parameter, meaning hash, salt, iteration count and output length, so you can reproduce a derivation from another system, test vectors, or decide how expensive your own settings should be.

How to use it

1. Enter the Password. It is masked, and derivation will not run if it is empty.
2. Keep the pre-filled Salt, a random 16-byte hex value, or type your own and flip the Salt is hex-encoded switch to match. Random salt makes a new one.
3. Choose the Hash algorithm, then set Iterations and Key length (bits).
4. Select Derive key and read the result in Hex or Base64, with its length shown in bytes and bits.

RFC 6070 test vector

Password: password, Salt: salt (switch off hex-encoded), HMAC-SHA-1, Iterations: 4096, Key length: 160 bits

4b007901b765489abead49d926f721d065a429c1

When to use it

• Matching a key that another application derived, by copying its hash, salt and iteration settings exactly.
• Checking your own PBKDF2 code against the published RFC 6070 vectors.
• Measuring how long a given iteration count takes in a browser before choosing it for a login flow.
• Deriving a fixed-length symmetric key from a passphrase for a quick encryption experiment.

Questions about PBKDF2 key generator

How many iterations should I use?

The defaults follow OWASP guidance of 600,000 for PBKDF2-HMAC-SHA256, and the page warns when you go below it. The count should be as high as your users can tolerate, and it must rise over time.

Why must the salt be random and unique?

A unique salt stops an attacker from precomputing tables or cracking many users' passwords in one pass. Use at least 16 random bytes per password, and store it next to the derived value.

What limits does the tool apply?

Iterations must be a whole number from 1 to 10,000,000, key length a multiple of 8 up to 8192 bits, and the salt cannot be empty. Invalid values produce an explanatory error instead of a result.

Does a longer key make the password harder to guess?

No. The password's entropy caps the security. Asking for more output than the hash produces, such as 512 bits from SHA-256, even makes defenders do extra work that an attacker testing the first block can skip.

Is PBKDF2 the best choice for password storage?

It is standardized and available everywhere, but it uses little memory, so GPUs attack it efficiently. Memory-hard functions such as scrypt or Argon2 resist that better where they are available.

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