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|
-- |
-- Module : Crypto.PubKey.Internal
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : experimental
-- Portability : Good
--
module Crypto.PubKey.Internal
( and'
, (&&!)
, dsaTruncHash
, dsaTruncHashDigest
) where
import Data.Bits (shiftR)
import Data.List (foldl')
import Crypto.Hash
import Crypto.Internal.ByteArray (ByteArrayAccess)
import Crypto.Number.Basic (numBits)
import Crypto.Number.Serialize
-- | This is a strict version of and
and' :: [Bool] -> Bool
and' l = foldl' (&&!) True l
-- | This is a strict version of &&.
(&&!) :: Bool -> Bool -> Bool
True &&! True = True
True &&! False = False
False &&! True = False
False &&! False = False
-- | Truncate and hash for DSA and ECDSA.
dsaTruncHash :: (ByteArrayAccess msg, HashAlgorithm hash) => hash -> msg -> Integer -> Integer
dsaTruncHash hashAlg = dsaTruncHashDigest . hashWith hashAlg
-- | Truncate a digest for DSA and ECDSA.
dsaTruncHashDigest :: HashAlgorithm hash => Digest hash -> Integer -> Integer
dsaTruncHashDigest digest n
| d > 0 = shiftR e d
| otherwise = e
where e = os2ip digest
d = hashDigestSize (getHashAlg digest) * 8 - numBits n
getHashAlg :: Digest hash -> hash
getHashAlg _ = undefined
|
