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-- |
-- Module : Crypto.Cipher.Types.AEAD
-- License : BSD-style
-- Maintainer : Vincent Hanquez <vincent@snarc.org>
-- Stability : Stable
-- Portability : Excellent
--
-- AEAD cipher basic types
--
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE Rank2Types #-}
module Crypto.Cipher.Types.AEAD where
import Crypto.Cipher.Types.Base
import Crypto.Internal.ByteArray (ByteArrayAccess, ByteArray)
import qualified Crypto.Internal.ByteArray as B
import Crypto.Internal.Imports
-- | AEAD Implementation
data AEADModeImpl st = AEADModeImpl
{ aeadImplAppendHeader :: forall ba . ByteArrayAccess ba => st -> ba -> st
, aeadImplEncrypt :: forall ba . ByteArray ba => st -> ba -> (ba, st)
, aeadImplDecrypt :: forall ba . ByteArray ba => st -> ba -> (ba, st)
, aeadImplFinalize :: st -> Int -> AuthTag
}
-- | Authenticated Encryption with Associated Data algorithms
data AEAD cipher = forall st . AEAD
{ aeadModeImpl :: AEADModeImpl st
, aeadState :: !st
}
-- | Append some header information to an AEAD context
aeadAppendHeader :: ByteArrayAccess aad => AEAD cipher -> aad -> AEAD cipher
aeadAppendHeader (AEAD impl st) aad = AEAD impl $ aeadImplAppendHeader impl st aad
-- | Encrypt some data and update the AEAD context
aeadEncrypt :: ByteArray ba => AEAD cipher -> ba -> (ba, AEAD cipher)
aeadEncrypt (AEAD impl st) ba = second (AEAD impl) $ aeadImplEncrypt impl st ba
-- | Decrypt some data and update the AEAD context
aeadDecrypt :: ByteArray ba => AEAD cipher -> ba -> (ba, AEAD cipher)
aeadDecrypt (AEAD impl st) ba = second (AEAD impl) $ aeadImplDecrypt impl st ba
-- | Finalize the AEAD context and return the authentication tag
aeadFinalize :: AEAD cipher -> Int -> AuthTag
aeadFinalize (AEAD impl st) = aeadImplFinalize impl st
-- | Simple AEAD encryption
aeadSimpleEncrypt :: (ByteArrayAccess aad, ByteArray ba)
=> AEAD a -- ^ A new AEAD Context
-> aad -- ^ Optional Authentication data header
-> ba -- ^ Optional Plaintext
-> Int -- ^ Tag length
-> (AuthTag, ba) -- ^ Authentication tag and ciphertext
aeadSimpleEncrypt aeadIni header input taglen = (tag, output)
where aead = aeadAppendHeader aeadIni header
(output, aeadFinal) = aeadEncrypt aead input
tag = aeadFinalize aeadFinal taglen
-- | Simple AEAD decryption
aeadSimpleDecrypt :: (ByteArrayAccess aad, ByteArray ba)
=> AEAD a -- ^ A new AEAD Context
-> aad -- ^ Optional Authentication data header
-> ba -- ^ Ciphertext
-> AuthTag -- ^ The authentication tag
-> Maybe ba -- ^ Plaintext
aeadSimpleDecrypt aeadIni header input authTag
| tag == authTag = Just output
| otherwise = Nothing
where aead = aeadAppendHeader aeadIni header
(output, aeadFinal) = aeadDecrypt aead input
tag = aeadFinalize aeadFinal (B.length authTag)
|
