diff --git a/Network/Mail/Mime/SES.hs b/Network/Mail/Mime/SES.hs
--- a/Network/Mail/Mime/SES.hs
+++ b/Network/Mail/Mime/SES.hs
@@ -8,14 +8,14 @@
 
 import           Control.Exception           (Exception, throwIO)
 import           Control.Monad.IO.Class      (MonadIO, liftIO)
-import           Crypto.Hash.CryptoAPI       (SHA256)
-import           Crypto.HMAC
+import           Crypto.Hash                 (Digest, SHA256, hmac,
+                                              hmacGetDigest)
+import           Data.Byteable               (toBytes)
 import           Data.ByteString             (ByteString)
 import           Data.ByteString.Base64      (encode)
 import qualified Data.ByteString.Char8       as S8
 import qualified Data.ByteString.Lazy        as L
 import           Data.Conduit                (Sink, await, ($$), (=$))
-import qualified Data.Serialize              as S
 import           Data.Text                   (Text)
 import qualified Data.Text                   as T
 import           Data.Time                   (getCurrentTime)
@@ -124,10 +124,4 @@
 
 makeSig :: ByteString -> ByteString -> ByteString
 makeSig payload key =
-      encode
-    $ S.encode
-    $ hmac' (MacKey key) payload
-      `asTypeOf` x
-  where
-    x :: SHA256
-    x = undefined
+    encode $ toBytes (hmacGetDigest $ hmac key payload :: Digest SHA256)
diff --git a/mime-mail-ses.cabal b/mime-mail-ses.cabal
--- a/mime-mail-ses.cabal
+++ b/mime-mail-ses.cabal
@@ -1,5 +1,5 @@
 Name:                mime-mail-ses
-Version:             0.2.2
+Version:             0.2.2.1
 Synopsis:            Send mime-mail messages via Amazon SES
 Homepage:            http://github.com/snoyberg/mime-mail
 License:             MIT
@@ -13,8 +13,6 @@
 Library
   Exposed-modules:     Network.Mail.Mime.SES
   Build-depends:       base               >= 4         && < 5
-                     , crypto-api         >= 0.6
-                     , cereal             >= 0.3
                      , base64-bytestring  >= 0.1
                      , bytestring         >= 0.9
                      , time               >= 1.1
@@ -24,9 +22,10 @@
                      , mime-mail          >= 0.3
                      , transformers       >= 0.2
                      , http-types         >= 0.6.8
-                     , cryptohash-cryptoapi
                      , xml-conduit
                      , xml-types
                      , text
                      , conduit
+                     , cryptohash         >= 0.7.3
+                     , byteable
   ghc-options: -Wall