diff --git a/Data/Bitlib.hs b/Data/Bitlib.hs
--- a/Data/Bitlib.hs
+++ b/Data/Bitlib.hs
@@ -12,7 +12,7 @@
 pack (x:[]) = fromIntegral x
 pack (x:xs) = (fromIntegral x) .|. ((pack xs) `shiftL` (bitSize x))
 
-unpack :: (Integral a, Bits a, Bits b) => a -> [b]
+unpack :: (Integral a, Bits a, Num b, Bits b) => a -> [b]
 unpack = doUnpack 0
     where doUnpack :: (Integral a, Bits a, Bits b) => Int -> a -> [b]
           doUnpack n x
diff --git a/Twofish.cabal b/Twofish.cabal
--- a/Twofish.cabal
+++ b/Twofish.cabal
@@ -1,5 +1,5 @@
 Name:          Twofish
-Version:       0.3
+Version:       0.3.1
 Category:      Cryptography, Codec
 Synopsis:      An implementation of the Twofish Symmetric-key cipher.
 Description:   Implements the Twofish symmetric block cipher, designed by: