| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell98 |
Crypto.PBKDF2
Description
Implementation of Password Based Key Derivation Function, from RSA labs.
See PKCS # 5 / RFC 2898 from rsa labs: and haskell cafe discussion on why password hashing is a good idea for web apps and a suggestion that this be implemented:
http://www.ietf.org/rfc/rfc2898.txt http://groups.google.com/group/fa.haskell/browse_thread/thread/66c7aeeb6e47764a/b15d9d74d68c002c
hashedpass = pbkdf2 ( Password . toOctets $ "password" ) ( Salt . toOctets $ "salt" )
- pbkdf2 :: Password -> Salt -> HashedPass
- pbkdf2' :: ([Word8] -> [Word8] -> [Word8], Integer) -> Integer -> Integer -> Password -> Salt -> HashedPass
- newtype Password = Password [Word8]
- newtype Salt = Salt [Word8]
- newtype HashedPass = HashedPass [Word8]
- toOctets :: Binary a => a -> [Word8]
- fromOctets :: Binary a => [Word8] -> a
Documentation
pbkdf2 :: Password -> Salt -> HashedPass Source
A reasonable default for rsa pbkdf2.
pbkdf2 = pbkdf2' (prfSHA512,64) 5000 64
SHA512 outputs 64 bytes. At least 1000 iters is suggested by PKCS#5 (rsa link above). I chose 5000 because this takes my computer a little over a second to compute a simple key derivation (see t test function in source)
Dklen of 64 seemed reasonable to me: if this is being stored in a database, doesn't take too much space.
Computational barriers can be raised by increasing number of iters
pbkdf2' :: ([Word8] -> [Word8] -> [Word8], Integer) -> Integer -> Integer -> Password -> Salt -> HashedPass Source
Password Based Key Derivation Function, from RSA labs.
pbkdf2' (prf,hlen) cIters dklen (Password pass) (Salt salt)
prf: pseudo random function
hlen: length of prf output
cIters: Number of iterations of prf
dklen: Length of the derived key (hashed password)
fromOctets :: Binary a => [Word8] -> a Source