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Newtype for hash values #9

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Newtype for hash values #9

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52d3826
Wrap a newtype around hash strings.
fisx Jan 21, 2016
d436818
Bump version.
fisx Jan 21, 2016
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21 changes: 12 additions & 9 deletions Crypto/BCrypt.hs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
>>> hashUsesPolicy fastBcryptHashingPolicy (p "$2y$14$xBBZdWgTa8fSU1aPFP5IxeVdUKfT7hUDjmusZEAiNBiYaYEGY/Sh6")
False
-}
module Crypto.BCrypt (HashingPolicy(..), hashPasswordUsingPolicy, validatePassword,
module Crypto.BCrypt (HashingPolicy(..), BCryptHash(..), hashPasswordUsingPolicy, validatePassword,
fastBcryptHashingPolicy, slowerBcryptHashingPolicy,
hashUsesPolicy, hashPassword, genSalt, genSaltUsingPolicy)
where
Expand Down Expand Up @@ -65,8 +65,11 @@ data HashingPolicy = HashingPolicy {
preferredHashAlgorithm :: BS.ByteString
}

newtype BCryptHash = BCryptHash { fromBCryptHash :: BS.ByteString }
deriving (Eq, Show)

-- | Hashes a password, using a hashing policy.
hashPasswordUsingPolicy :: HashingPolicy -> BS.ByteString -> IO (Maybe BS.ByteString)
hashPasswordUsingPolicy :: HashingPolicy -> BS.ByteString -> IO (Maybe BCryptHash)
hashPasswordUsingPolicy hp pw = do
ms <- genSaltUsingPolicy hp
return $ do
Expand All @@ -78,12 +81,12 @@ hashPasswordUsingPolicy hp pw = do
-- Note: If a password validates successfully, it is a good idea to check if the
-- password is up to the current policy using hashUsesPolicy, and re-hashing it
-- if not.
validatePassword :: BS.ByteString -> BS.ByteString -> Bool
validatePassword h pw =
validatePassword :: BCryptHash -> BS.ByteString -> Bool
validatePassword (BCryptHash h) pw =
case hashPassword pw h
of
Nothing -> False
Just h2 -> h2 `constEq` h
Just (BCryptHash h2) -> h2 `constEq` h

-- | A policy that allows passwords to be hashed reasonably quickly, but for that
-- reason isn't suitable for high security applications.
Expand All @@ -99,8 +102,8 @@ slowerBcryptHashingPolicy = fastBcryptHashingPolicy { preferredHashCost = 14 }

-- | Check whether a password hash is consistent with the current policy, or if
-- it should be updated.
hashUsesPolicy :: HashingPolicy -> BS.ByteString -> Bool
hashUsesPolicy (HashingPolicy phc pha) str =
hashUsesPolicy :: HashingPolicy -> BCryptHash -> Bool
hashUsesPolicy (HashingPolicy phc pha) (BCryptHash str) =
let phaLen = BS.length pha
strPref = BS.take phaLen str
strInfo = BS.take 2 (BS.drop phaLen str)
Expand All @@ -114,8 +117,8 @@ hashUsesPolicy (HashingPolicy phc pha) str =
-- hash will cause the same settings to be used again.
-- You can create a hash using genSalt.
-- Result: Just hash on success, Nothing on failure (invalid settings).
hashPassword :: BS.ByteString -> BS.ByteString -> Maybe BS.ByteString
hashPassword pw setting =
hashPassword :: BS.ByteString -> BS.ByteString -> Maybe BCryptHash
hashPassword pw setting = fmap BCryptHash $
U.unsafePerformIO $ BS.useAsCString pw $
\pw' -> BS.useAsCString setting $
\setting' -> alloca $ \data' -> alloca $ \dlen -> do
Expand Down
2 changes: 1 addition & 1 deletion bcrypt.cabal
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
Name: bcrypt
Version: 0.0.8
Version: 0.1.0
Cabal-Version: >= 1.6
Build-Type: Simple
License: BSD3
Expand Down