diff --git a/Crypto/PubKey/RSA/OAEP.hs b/Crypto/PubKey/RSA/OAEP.hs
index 2296e03..6df7fce 100644
--- a/Crypto/PubKey/RSA/OAEP.hs
+++ b/Crypto/PubKey/RSA/OAEP.hs
@@ -21,16 +21,16 @@ module Crypto.PubKey.RSA.OAEP
     , decryptSafer
     ) where
 
-import Crypto.Hash
-import Crypto.Random.Types
-import Crypto.PubKey.RSA.Types
-import Crypto.PubKey.MaskGenFunction
-import Crypto.PubKey.RSA.Prim
-import Crypto.PubKey.RSA (generateBlinder)
-import Crypto.PubKey.Internal (and')
-import Data.ByteString (ByteString)
+import           Crypto.Hash
+import           Crypto.Random.Types
+import           Crypto.PubKey.RSA.Types
+import           Crypto.PubKey.MaskGenFunction
+import           Crypto.PubKey.RSA.Prim
+import           Crypto.PubKey.RSA (generateBlinder)
+import           Crypto.PubKey.Internal (and')
+import           Data.ByteString (ByteString)
 import qualified Data.ByteString as B
-import Data.Bits (xor)
+import           Data.Bits (xor)
 
 import qualified Crypto.Internal.ByteArray as B (convert)
 
diff --git a/Crypto/PubKey/RSA/PKCS15.hs b/Crypto/PubKey/RSA/PKCS15.hs
index 29cbfe0..933e273 100644
--- a/Crypto/PubKey/RSA/PKCS15.hs
+++ b/Crypto/PubKey/RSA/PKCS15.hs
@@ -22,28 +22,32 @@ module Crypto.PubKey.RSA.PKCS15
     , verify
     ) where
 
-import Crypto.Random.Types
-import Crypto.PubKey.Internal (and')
-import Crypto.PubKey.RSA.Types
-import Data.ByteString (ByteString)
-import qualified Data.ByteString as B
-import Crypto.PubKey.RSA.Prim
-import Crypto.PubKey.RSA (generateBlinder)
-import Crypto.PubKey.HashDescr
+import           Crypto.Random.Types
+import           Crypto.PubKey.Internal (and')
+import           Crypto.PubKey.RSA.Types
+import           Crypto.PubKey.RSA.Prim
+import           Crypto.PubKey.RSA (generateBlinder)
+import           Crypto.PubKey.HashDescr
+
+import           Data.ByteString (ByteString)
+
+import           Crypto.Internal.ByteArray (ByteArray, Bytes)
+import qualified Crypto.Internal.ByteArray as B
 
 -- | This produce a standard PKCS1.5 padding for encryption
-pad :: MonadRandom m => Int -> ByteString -> m (Either Error ByteString)
+pad :: (MonadRandom m, ByteArray message) => Int -> message -> m (Either Error message)
 pad len m
     | B.length m > len - 11 = return (Left MessageTooLong)
     | otherwise             = do
         padding <- getNonNullRandom (len - B.length m - 3)
-        return $ Right $ B.concat [ B.singleton 0, B.singleton 2, padding, B.singleton 0, m ]
+        return $ Right $ B.concat [ B.pack [0,2], padding, B.pack [0], m ]
 
-  where {- get random non-null bytes -}
-    getNonNullRandom :: MonadRandom m => Int -> m ByteString
+  where
+    -- get random non-null bytes
+    getNonNullRandom :: (ByteArray bytearray, MonadRandom m) => Int -> m bytearray
     getNonNullRandom n = do
         bs0 <- getRandomBytes n
-        let bytes = B.pack $ filter (/= 0) $ B.unpack $ bs0
+        let bytes = B.pack $ filter (/= 0) $ B.unpack (bs0 :: Bytes)
             left  = n - B.length bytes
         if left == 0
             then return bytes
@@ -51,25 +55,25 @@ pad len m
                     return (bytes `B.append` bend)
 
 -- | Produce a standard PKCS1.5 padding for signature
-padSignature :: Int -> ByteString -> Either Error ByteString
+padSignature :: ByteArray signature => Int -> signature -> Either Error signature
 padSignature klen signature
     | klen < siglen+1 = Left SignatureTooLong
-    | otherwise       = Right $ B.concat [B.singleton 0,B.singleton 1,padding,B.singleton 0,signature]
-    where
+    | otherwise       = Right (B.pack padding `B.append` signature)
+  where
         siglen    = B.length signature
-        padding   = B.replicate (klen - siglen - 3) 0xff
+        padding   = 0 : 1 : (replicate (klen - siglen - 3) 0xff ++ [0])
 
 -- | Try to remove a standard PKCS1.5 encryption padding.
-unpad :: ByteString -> Either Error ByteString
+unpad :: ByteArray bytearray => bytearray -> Either Error bytearray
 unpad packed
     | paddingSuccess = Right m
     | otherwise      = Left MessageNotRecognized
-    where
+  where
         (zt, ps0m)   = B.splitAt 2 packed
         (ps, zm)     = B.span (/= 0) ps0m
         (z, m)       = B.splitAt 1 zm
-        paddingSuccess = and' [ zt == "\x00\x02"
-                              , z  == "\x00"
+        paddingSuccess = and' [ zt `B.constEq` (B.pack [0,2] :: Bytes)
+                              , z == B.zero 1
                               , B.length ps >= 8
                               ]
 
diff --git a/Crypto/PubKey/RSA/PSS.hs b/Crypto/PubKey/RSA/PSS.hs
index c3332df..2bf8871 100644
--- a/Crypto/PubKey/RSA/PSS.hs
+++ b/Crypto/PubKey/RSA/PSS.hs
@@ -16,17 +16,18 @@ module Crypto.PubKey.RSA.PSS
     , verify
     ) where
 
-import Crypto.Random.Types
-import Crypto.PubKey.RSA.Types
-import Data.ByteString (ByteString)
-import qualified Data.ByteString as B
-import Crypto.PubKey.RSA.Prim
-import Crypto.PubKey.RSA (generateBlinder)
-import Crypto.PubKey.MaskGenFunction
-import Crypto.Hash
-import Data.Bits (xor, shiftR, (.&.))
-import Data.Word
+import           Crypto.Random.Types
+import           Crypto.PubKey.RSA.Types
+import           Crypto.PubKey.RSA.Prim
+import           Crypto.PubKey.RSA (generateBlinder)
+import           Crypto.PubKey.MaskGenFunction
+import           Crypto.Hash
+import           Data.Bits (xor, shiftR, (.&.))
+import           Data.Word
+
 import qualified Crypto.Internal.ByteArray as B (convert)
+import           Data.ByteString (ByteString)
+import qualified Data.ByteString as B
 
 -- | Parameters for PSS signature/verification.
 data PSSParams hash = PSSParams
diff --git a/Crypto/PubKey/RSA/Prim.hs b/Crypto/PubKey/RSA/Prim.hs
index 26f38c2..2dc964e 100644
--- a/Crypto/PubKey/RSA/Prim.hs
+++ b/Crypto/PubKey/RSA/Prim.hs
@@ -13,10 +13,10 @@ module Crypto.PubKey.RSA.Prim
     , ep
     ) where
 
-import Data.ByteString (ByteString)
-import Crypto.PubKey.RSA.Types
-import Crypto.Number.ModArithmetic (expFast, expSafe)
-import Crypto.Number.Serialize (os2ip, i2ospOf_)
+import           Data.ByteString (ByteString)
+import           Crypto.PubKey.RSA.Types
+import           Crypto.Number.ModArithmetic (expFast, expSafe)
+import           Crypto.Number.Serialize (os2ip, i2ospOf_)
 
 {- dpSlow computes the decrypted message not using any precomputed cache value.
    only n and d need to valid. -}
diff --git a/Crypto/PubKey/RSA/Types.hs b/Crypto/PubKey/RSA/Types.hs
index a173eb0..0aa1313 100644
--- a/Crypto/PubKey/RSA/Types.hs
+++ b/Crypto/PubKey/RSA/Types.hs
@@ -19,7 +19,7 @@ module Crypto.PubKey.RSA.Types
     , private_e
     ) where
 
-import Data.Data
+import           Data.Data
 
 -- | Blinder which is used to obfuscate the timing
 -- of the decryption primitive (used by decryption and signing).