diff --git a/eap.cabal b/eap.cabal
--- a/eap.cabal
+++ b/eap.cabal
@@ -1,5 +1,5 @@
 name:                eap
-version:             0.7.0.0
+version:             0.8.0.0
 synopsis:            Extensible Authentication Protocol (EAP)
 description:         This module provides types and on the wire de/coding of EAP packets as per RFC 3748
 homepage:            https://github.com/erickg/eap#readme
diff --git a/src/Network/EAP/Authentication.hs b/src/Network/EAP/Authentication.hs
--- a/src/Network/EAP/Authentication.hs
+++ b/src/Network/EAP/Authentication.hs
@@ -44,7 +44,7 @@
 authenticateMSCHAPv2
     :: MSCHAPv2Data  -- ^ Decoded data from the MSCHAPv2 response
      -> ByteString    -- ^ Authenticator challenge sent to the peer on a previous request
-     -> SB.ByteString -- ^ Authenticating user password NT hash (MD4)
+     -> ByteString    -- ^ Authenticating user password NT hash (MD4)
      -> Except CryptoError Bool -- ^ Returns either an error from one of the encryption
                                -- routines or a boolean indicating whether the user
                                -- response matches the expected value
@@ -65,13 +65,13 @@
                                     -- request
                    ->  ByteString    -- ^ Challenge sent back by authenticating peer
                    ->  ByteString    -- ^ MSCHAP username
-                   ->  SB.ByteString -- ^ NT hash (MD4) of user password
+                   ->  ByteString    -- ^ NT hash (MD4) of user password
                    ->  Except CryptoError SB.ByteString -- ^ Returns either an error from one of
                                                        -- the encryption routines or the
                                                        -- calculated NT response
 generateNTResponse authenticatorChallenge peerChallenge username passwordHash = do
     let challenge        = challengeHash peerChallenge authenticatorChallenge username
-        zPasswordHash    = passwordHash `SB.append` SB.replicate 5 0 -- pad to 21 octets
+        zPasswordHash    = (toStrict passwordHash) `SB.append` SB.replicate 5 0 -- pad to 21 octets
         (pHash0, rest)   = SB.splitAt 7 zPasswordHash
         (pHash1, pHash2) = SB.splitAt 7 rest
     r0 <- encryptDES pHash0 challenge