How about the following? The main doubts I'm having at this point concern the takerandom part. Does this seem reasonable? Also, someone in the thread mentioned that a calculation that took a couple of seconds to complete was a good thing because it makes dictionary cracking harder. But makeSaltedPasswordLinux "meh" is virtually instantaneous, so I guess I'm doing something wrong? Thanks for advice! thomas. thartman@thartman-laptop:~/hackage/HAppSHelpers>cat HAppS/Helpers/Security.hs -- | Password hashes are based on a salt from a source of randomness (eg /dev/urandom), and -- | the SHA512 hashing function module HAppS.Helpers.Security ( makeSaltedPassword, makeSaltedPasswordLinux, checkpass ) where import qualified Data.ByteString.Char8 as B import qualified Data.ByteString as B' import Control.Monad.Error import System.IO.Error import Random import Data.Digest.SHA512 (hash) import Data.Char data SaltedPassword = SaltedPassword HashedPass Salt deriving Show newtype Password = Password String deriving Show newtype Salt = Salt String deriving Show newtype HashedPass = HashedPass String deriving (Eq, Show) checkpass :: Password -> SaltedPassword -> Bool checkpass passattempt ( SaltedPassword hashedPass salt ) = let hashedPassAttempt = hashpass passattempt salt in hashedPassAttempt == hashedPass hashpass :: Password -> Salt -> HashedPass hashpass (Password p) (Salt s) = HashedPass . B.unpack . B'.pack . hash . B'.unpack . B.pack $ p ++ s -- | This works at least on ubuntu hardy heron, I don't know how portable it is -- > makeSaltedPasswordLinux p = getSaltedPassword $ readFile "/dev/urandom") makeSaltedPasswordLinux :: Password -> IO SaltedPassword makeSaltedPasswordLinux = makeSaltedPassword $ readFile "/dev/urandom" makeSaltedPassword :: IO String -> Password -> IO SaltedPassword makeSaltedPassword randomsource pass = do etR <- try $ return . takerandom =<< randomsource case etR of Left e -> fail . show $ e Right s -> do let salt = Salt s hp = hashpass pass salt return $ SaltedPassword hp salt takerandom :: String -> String takerandom = show . fst . next . mkStdGen . read . concat . map (show . ord) . take 1000 2008/11/25 Bulat Ziganshin <bulat.ziganshin@gmail.com>:
Hello Thomas,
Tuesday, November 25, 2008, 6:39:27 PM, you wrote:
Just to note, the comment about md5 is incorrect. I switched to SHA512 as you can see in the code.
really? :)
Right s -> -- return . show . md5 . L.pack $ p ++ s
typical salt usage is generation of new salt for every encryption operation and storing together with encrypted data
-- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com