Add an exceptions-based interface

Crypto/Classes/Exceptions.hs

@@ -0,0 +1,59 @@
+-- |The module mirrors 'Crypto.Classes' except that it throws all errors as
+-- exceptions instead of returning types of @Either error result@.
+{-# LANGUAGE DeriveDataTypeable #-}
+module Crypto.Classes.Exceptions 
+    ( C.Hash(..)
+    , C.hashFunc, C.hashFunc'
+    , C.BlockCipher, C.blockSize, C.encryptBlock, C.decryptBlock
+    , C.keyLength
+    , C.getIVIO, C.blockSizeBytes, C.keyLengthBytes, C.buildKeyIO
+    , C.AsymCipher, C.publicKeyLength, C.privateKeyLength, C.buildKeyPairIO
+    , C.Signing, C.signingKeyLength, C.verifyingKeyLength, C.verify
+    , C.incIV, C.zeroIV
+    -- Modes
+    , C.ecb, C.unEcb, C.cbc, C.unCbc, C.ctr, C.unCtr, C.ctrLazy, C.unCtrLazy
+    , C.cfb, C.unCfb, C.ofb, C.unOfb, C.cbcLazy, C.unCbcLazy, C.sivLazy, C.unSivLazy
+    , C.siv, C.unSiv, C.ecbLazy, C.unEcbLazy, C.cfbLazy, C.unCfbLazy, C.ofbLazy
+    , C.unOfbLazy
+    -- Wrapped functions
+    , buildKey, getIV, buildKeyGen
+    , buildKeyPair, encryptAsym, decryptAsym
+    ) where
+
+import           Crypto.Random
+import           Crypto.Types
+import qualified Crypto.Classes    as C
+import qualified Control.Exception as X
+import qualified Data.ByteString   as B
+import           Data.Data
+import           Data.Typeable
+
+data CipherError = GenError GenError
+                 | KeyGenFailure
+        deriving (Show, Read, Eq, Ord, Data, Typeable)
+
+instance X.Exception CipherError
+
+mExcept :: (X.Exception e) => e -> Maybe a -> a
+mExcept e = maybe (X.throw e) id
+
+eExcept :: (X.Exception e) => Either e a -> a
+eExcept = either X.throw id
+
+buildKey :: C.BlockCipher k => B.ByteString -> k
+buildKey = mExcept KeyGenFailure . C.buildKey
+
+getIV :: (C.BlockCipher k, CryptoRandomGen g) => g -> (IV k, g)
+getIV = eExcept . C.getIV
+
+buildKeyGen :: (CryptoRandomGen g, C.BlockCipher k) => g -> (k, g)
+buildKeyGen = eExcept . C.buildKeyGen
+
+buildKeyPair :: (CryptoRandomGen g, C.AsymCipher p v) => g -> BitLength -> ((p,v), g)
+buildKeyPair g = eExcept . C.buildKeyPair g
+
+encryptAsym :: (CryptoRandomGen g, C.AsymCipher p v) => g -> p -> B.ByteString -> (B.ByteString, g)
+encryptAsym g p = eExcept . C.encryptAsym g p
+
+decryptAsym :: (CryptoRandomGen g, C.AsymCipher p v) => g -> v -> B.ByteString -> (B.ByteString, g)
+decryptAsym g v = eExcept . C.decryptAsym g v

crypto-api.cabal

@@ -43,7 +43,7 @@ Library
   hs-source-dirs:
   exposed-modules: Crypto.Classes, Crypto.Types, Crypto.HMAC,
                    Crypto.Random, Crypto.Padding, Crypto.Modes,
-                   Crypto.Util
+                   Crypto.Util, Crypto.Classes.Exceptions
   other-modules: Crypto.CPoly
   extensions: ForeignFunctionInterface, MultiParamTypeClasses,
               BangPatterns, FunctionalDependencies, FlexibleInstances,