diff --git a/Data/Bson.hs b/Data/Bson.hs
--- a/Data/Bson.hs
+++ b/Data/Bson.hs
@@ -32,8 +32,9 @@
 import Data.Time.Format ()  -- for Show and Read instances of UTCTime
 import Data.List (find, findIndex)
 import Data.Bits (shift, (.|.))
-import Data.ByteString.Char8 (ByteString, pack)
-import Data.Digest.OpenSSL.MD5 (md5sum)
+import qualified Data.ByteString as BS (ByteString, unpack, take)
+import qualified Data.ByteString.Char8 as BSC (pack)
+import qualified Crypto.Hash.MD5 as MD5 (hash)
 import Numeric (readHex, showHex)
 import Network.BSD (getHostName)
 import System.IO.Unsafe (unsafePerformIO)
@@ -349,15 +350,15 @@
 
 -- ** Binary types
 
-newtype Binary = Binary ByteString  deriving (Typeable, Show, Read, Eq)
+newtype Binary = Binary BS.ByteString  deriving (Typeable, Show, Read, Eq)
 
-newtype Function = Function ByteString  deriving (Typeable, Show, Read, Eq)
+newtype Function = Function BS.ByteString  deriving (Typeable, Show, Read, Eq)
 
-newtype UUID = UUID ByteString  deriving (Typeable, Show, Read, Eq)
+newtype UUID = UUID BS.ByteString  deriving (Typeable, Show, Read, Eq)
 
-newtype MD5 = MD5 ByteString  deriving (Typeable, Show, Read, Eq)
+newtype MD5 = MD5 BS.ByteString  deriving (Typeable, Show, Read, Eq)
 
-newtype UserDefined = UserDefined ByteString  deriving (Typeable, Show, Read, Eq)
+newtype UserDefined = UserDefined BS.ByteString  deriving (Typeable, Show, Read, Eq)
 
 -- ** Regex
 
@@ -401,7 +402,7 @@
 	return $ Oid time (composite machineId pid inc)
  where
 	machineId :: Word24
-	machineId = unsafePerformIO (fst . head . readHex . take 6 . md5sum . pack <$> getHostName)
+	machineId = unsafePerformIO (makeWord24 . BS.unpack . BS.take 3 . MD5.hash . BSC.pack <$> getHostName)
  	{-# NOINLINE machineId #-}
  	counter :: IORef Word24
  	counter = unsafePerformIO (newIORef 0)
@@ -417,6 +418,9 @@
 wrap24 :: Word24 -> Word24
 wrap24 n = n `mod` 0x1000000
 
+makeWord24 :: [Word8] -> Word24
+-- ^ Put last 3 bytes into a Word24. Expected to be called on very short list
+makeWord24 = foldl (\a b -> a `shift` 8 .|. fromIntegral b) 0
 
 {- Authors: Tony Hannan <tony@10gen.com>
    Copyright 2010 10gen Inc.
diff --git a/bson.cabal b/bson.cabal
--- a/bson.cabal
+++ b/bson.cabal
@@ -1,5 +1,5 @@
 Name: bson
-Version: 0.1.2
+Version: 0.1.3
 Synopsis: BSON documents are JSON-like objects with a standard binary encoding
 Description: A BSON Document is an untyped (dynamically type-checked) record. I.e. it is a list of name-value pairs, where a Value is a single sum type with constructors for basic types (Bool, Int, Float, String, and Time), compound types (List, and (embedded) Document), and special types (Binary, Javascript, ObjectId, RegEx, and a few others).
 	.
@@ -10,6 +10,6 @@
 Maintainer: Tony Hannan <tony@10gen.com>
 License: OtherLicense
 License-file: LICENSE
-Build-Depends: base < 5, time, bytestring, network, nano-md5, binary, data-binary-ieee754, compact-string-fix, mtl >= 2
+Build-Depends: base < 5, time, bytestring, network, cryptohash, binary, data-binary-ieee754, compact-string-fix, mtl >= 2
 Build-Type: Simple
 Exposed-modules: Data.UString, Data.Bson, Data.Bson.Binary