diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,10 @@
   - Describe change #2
   - Indicate if changes are major, minor, or patch changes.
 ```
+- [#30](https://github.com/jhickner/smtp-mail/pull/30) @typetetris
+    - Replace `cryptohash` dependency with `cryptonite`.
+      `cryptohash` is deprecated and `cryptonite` offers HMAC MD5
+      directly.
 
 ## 0.2.0.0
 
diff --git a/Network/Mail/SMTP/Auth.hs b/Network/Mail/SMTP/Auth.hs
--- a/Network/Mail/SMTP/Auth.hs
+++ b/Network/Mail/SMTP/Auth.hs
@@ -6,13 +6,14 @@
     auth,
 ) where
 
-import Crypto.Hash.MD5 (hash)
+import Crypto.MAC.HMAC (hmac, HMAC)
+import Crypto.Hash.Algorithms (MD5)
+import Data.ByteArray (copyAndFreeze)
 import qualified Data.ByteString.Base16 as B16  (encode)
 import qualified Data.ByteString.Base64 as B64  (encode)
 
 import Data.ByteString  (ByteString)
 import Data.List
-import Data.Bits
 import qualified Data.ByteString       as B
 import qualified Data.ByteString.Char8 as B8    (unwords)
 
@@ -39,14 +40,9 @@
 b64Encode = B64.encode . toAscii
 
 hmacMD5 :: ByteString -> ByteString -> ByteString
-hmacMD5 text key = hash (okey <> hash (ikey <> text))
-    where key' = if B.length key > 64
-                 then hash key <> B.replicate 48 0
-                 else key <> B.replicate (64-B.length key) 0
-          ipad = B.replicate 64 0x36
-          opad = B.replicate 64 0x5c
-          ikey = B.pack $ B.zipWith xor key' ipad
-          okey = B.pack $ B.zipWith xor key' opad
+hmacMD5 text key =
+    let mac = hmac key text :: HMAC MD5
+    in copyAndFreeze mac (const $ return ())
 
 encodePlain :: UserName -> Password -> ByteString
 encodePlain user pass = b64Encode $ intercalate "\0" [user, user, pass]
diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -62,6 +62,9 @@
 addresses you can import ```Network.Mail.Mime``` and construct ```Mail```
 objects manually.
 
+### Caveat
+
+You will encounter authentication errors if you try to connect to an SMTP server that expects SSL. If that's what you're looking to do, try [HaskellNet-SSL](http://hackage.haskell.org/package/HaskellNet-SSL).
 
 ### Thanks
 
diff --git a/smtp-mail.cabal b/smtp-mail.cabal
--- a/smtp-mail.cabal
+++ b/smtp-mail.cabal
@@ -1,5 +1,5 @@
 name:                smtp-mail
-version:             0.2.0.0
+version:             0.2.0.1
 synopsis:            Simple email sending via SMTP
 description:         This packages provides a simple interface for mail over SMTP. PLease see the README for more information.
 homepage:            http://github.com/jhickner/smtp-mail
@@ -10,7 +10,7 @@
 -- copyright:
 category:            Network
 build-type:          Simple
-cabal-version:       >=1.8
+cabal-version:       >=1.10
 
 extra-source-files:
     README.md
@@ -21,6 +21,7 @@
   location: git@github.com:jhickner/smtp-mail.git
 
 library
+  default-language: Haskell2010
   exposed-modules:
     Network.Mail.SMTP
     Network.Mail.SMTP.Auth
@@ -34,11 +35,12 @@
                , base64-bytestring
                , bytestring
                , connection
-               , cryptohash
                , filepath
                , mime-mail
                , network
                , network-bsd
                , text
+               , cryptonite
+               , memory
 
   ghc-options: -Wall -fwarn-tabs