diff --git a/Crypto/HMAC.hs b/Crypto/HMAC.hs
--- a/Crypto/HMAC.hs
+++ b/Crypto/HMAC.hs
@@ -35,7 +35,7 @@
          LT -> B.append k (B.replicate (blen - keylen) 0x00)
   ko = B.map (`xor` 0x5c) k'
   ki = fc $ B.map (`xor` 0x36) k'
-  fc = L.fromChunks . \s -> [s]
+  fc = L.fromStrict
 
 -- | @hmac k msg@ will compute an authentication code for @msg@ using key @k@
 hmac' :: (Hash c d) => MacKey c d -> B.ByteString -> d
diff --git a/crypto-api.cabal b/crypto-api.cabal
--- a/crypto-api.cabal
+++ b/crypto-api.cabal
@@ -1,5 +1,5 @@
 name:           crypto-api
-version:        0.12.1
+version:        0.12.2
 license:        BSD3
 license-file:   LICENSE
 copyright:      Thomas DuBuisson <thomas.dubuisson@gmail.com>