diff --git a/Data/RFC1751.hs b/Data/RFC1751.hs
--- a/Data/RFC1751.hs
+++ b/Data/RFC1751.hs
@@ -13,7 +13,8 @@
 import qualified Data.ByteString.Lazy as BL
 import Data.Bits
 import Data.Char
-import Data.List
+import Data.Vector (Vector, (!), fromList)
+import qualified Data.Vector as V
 
 encodeWord64 :: Word64 -> ByteString
 encodeWord64 = BS.concat . BL.toChunks . encode
@@ -25,7 +26,7 @@
 mnemonicToKey :: String -> Maybe ByteString
 mnemonicToKey s = do
     guard $ length ws == 12
-    BS.concat <$> mapM ((encodeWord64 <$>) . wordsToKey) [ws1, ws2]
+    BS.concat <$> mapM ((encodeWord64 <$>) . wordsToKey) [fromList ws1, fromList ws2]
   where
     ws = words $ map toUpper s
     (ws1, ws2) = splitAt 6 ws
@@ -40,21 +41,21 @@
 
 keyToWords :: Word64 -> [String]
 keyToWords key =
-    map ((dict !!) . fromIntegral) indices
+    map ((dict !) . fromIntegral) indices
   where
     keyCheckSum = checkSum key
     tempIndices = map (\start -> extract key start 11) [0,11..55]
     indices = init tempIndices ++ [last tempIndices .|. keyCheckSum]
 
-wordsToKey :: [String] -> Maybe Word64
+wordsToKey :: Vector String -> Maybe Word64
 wordsToKey ws = do
-    let findWord w   = fromIntegral <$> elemIndex w dict
-        maybeIndices = sequence $ map findWord ws
+    let findWord w   = fromIntegral <$> V.elemIndex w dict
+        maybeIndices = V.sequence $ V.map findWord ws
     indices <- maybeIndices
     let buildKey acc (bits, index) = (index `shift` bits) .|. acc
-        key = foldl buildKey 0 $ zip [53,42..(-2)] indices
+        key = V.foldl buildKey 0 $ V.zip (fromList [53,42..(-2)]) indices
         computedSum = checkSum key
-        providedSum = last indices .&. 0x03
+        providedSum = V.last indices .&. 0x03
     guard $ providedSum == computedSum
     return key
 
@@ -62,7 +63,7 @@
 checkSum key =
     pairSum .&. 0x03
   where
-    pairSum = sum $ map (flip (extract key) $ 2) [0,2..62]
+    pairSum = sum $ map (flip (extract key) 2) [0,2..62]
 
 extract :: Word64 -> Int -> Int -> Word64
 extract key start len =
@@ -72,8 +73,8 @@
     mask = complement $ 0xffffffffffffffff `shiftL` count
     temp = key `shiftR` (64 - start - count) .&. mask
 
-dict :: [String]
-dict =
+dict :: Vector String
+dict = fromList
   [ "A", "ABE", "ACE", "ACT", "AD", "ADA", "ADD", "AGO", "AID"
   , "AIM", "AIR", "ALL", "ALP", "AM", "AMY", "AN", "ANA", "AND"
   , "ANN", "ANT", "ANY", "APE", "APS", "APT", "ARC", "ARE", "ARK"
diff --git a/RFC1751.cabal b/RFC1751.cabal
--- a/RFC1751.cabal
+++ b/RFC1751.cabal
@@ -1,8 +1,5 @@
--- Initial RFC1751.cabal generated by cabal init.  For further 
--- documentation, see http://haskell.org/cabal/users-guide/
-
 name:                RFC1751
-version:             0.3.0.1
+version:             0.3.1.0
 synopsis:            RFC-1751 library for Haskell
 description:         Convert 128-bit ByteString to/from 12 English words.
 homepage:            https://github.com/xenog/RFC1751
@@ -10,22 +7,22 @@
 license-file:        UNLICENSE
 author:              Jean-Pierre Rupp
 maintainer:          root@haskoin.com
--- copyright:           
 category:            Data
 build-type:          Simple
 cabal-version:       >=1.8
 
 source-repository head
     type:     git
-    location: https://github.com/xenog/RFC1751.git
+    location: https://github.com/xenog/rfc-1751.git
 
 library
   exposed-modules:   Data.RFC1751
   build-depends:     base ==4.*,
                      binary,
-                     bytestring
+                     bytestring,
+                     vector
 
-test-suite test-haskoin-crypto
+test-suite test-rfc1751
     type:              exitcode-stdio-1.0
     main-is:           Main.hs
     other-modules:     Tests,
@@ -33,6 +30,7 @@
     build-depends:     base,
                        binary,
                        bytestring,
+                       vector,
                        RFC1751,
                        QuickCheck,
                        test-framework,
diff --git a/tests/Units.hs b/tests/Units.hs
--- a/tests/Units.hs
+++ b/tests/Units.hs
@@ -86,7 +86,7 @@
     | otherwise = error "integerToBS not defined for negative values"
   where 
     f 0 = Nothing
-    f x = Just $ (fromInteger x :: Word8, x `shiftR` 8)
+    f x = Just (fromInteger x :: Word8, x `shiftR` 8)
 
 hexToBS :: String -> ByteString
 hexToBS str
@@ -97,7 +97,7 @@
     z2    = BS.replicate (fromIntegral $ length z `div` 2) 0
     r1    = readHex r
     r2 | null r    = BS.empty
-       | null r1   = error $ "cannot read hex"
+       | null r1   = error "cannot read hex"
        | otherwise = integerToBS $ fst $ head r1
 
 vectors :: [TestVector]