diff --git a/Crypto/Hash/Types.hs b/Crypto/Hash/Types.hs
index 9f17cd2..211744a 100644
--- a/Crypto/Hash/Types.hs
+++ b/Crypto/Hash/Types.hs
@@ -20,7 +20,6 @@ import Crypto.Internal.Memory
 import Data.Byteable
 import qualified Data.ByteString.Char8 as BC
 import Crypto.Hash.Utils (toHex)
-import Data.Word
 
 -- | Class representing hashing algorithms.
 --
diff --git a/Crypto/Internal/Compat.hs b/Crypto/Internal/Compat.hs
index 97c0212..80ae332 100644
--- a/Crypto/Internal/Compat.hs
+++ b/Crypto/Internal/Compat.hs
@@ -17,6 +17,9 @@ module Crypto.Internal.Compat
 import System.IO.Unsafe
 #if MIN_VERSION_base(4,5,0)
 import Data.Bits (popCount)
+#else
+import Data.Word (Word64)
+import Data.Bits (testBit, shiftR)
 #endif
 
 -- | perform io for hashes that do allocation and ffi.