diff --git a/Data/Vhd/Const.hs b/Data/Vhd/Const.hs
new file mode 100644
--- /dev/null
+++ b/Data/Vhd/Const.hs
@@ -0,0 +1,6 @@
+module Data.Vhd.Const
+    ( sectorLength
+    ) where
+
+sectorLength :: Num a => a
+sectorLength = 512
diff --git a/Data/Vhd/Crypt.hs b/Data/Vhd/Crypt.hs
--- a/Data/Vhd/Crypt.hs
+++ b/Data/Vhd/Crypt.hs
@@ -15,7 +15,7 @@
 import Data.Bits (shiftR)
 import Data.Vhd.Types (VirtualBlockAddress(..), BlockByteAddress(..))
 import Crypto.Hash.SHA256 (hash)
-import Crypto.Cipher.AES
+import Crypto.Cipher.AES (AES, initAES, encryptXTS, decryptXTS)
 import System.FilePath
 import System.Directory
 import qualified Data.ByteString as B
diff --git a/vhd.cabal b/vhd.cabal
--- a/vhd.cabal
+++ b/vhd.cabal
@@ -1,5 +1,5 @@
 Name:                vhd
-Version:             0.2.1
+Version:             0.2.2
 Synopsis:            Provides functions to inspect and manipulate virtual hard disk (VHD) files.
 Description:         Provides functions to inspect and manipulate virtual hard disk (VHD) files, according to the VHD specification (version 1.0).
 Author:              Jonathan Knowles, Vincent Hanquez
@@ -40,6 +40,7 @@
                      Data.Vhd.Bat
                      Data.Vhd.Batmap
                      Data.Vhd.Crypt
+                     Data.Vhd.Const
                      Data.Vhd.Bitmap
                      Data.Vhd.Block
                      Data.Vhd.Checksum