diff --git a/radius.cabal b/radius.cabal
--- a/radius.cabal
+++ b/radius.cabal
@@ -1,5 +1,5 @@
 name:                radius
-version:             0.2.0.0
+version:             0.3.0.0
 synopsis:            Remote Authentication Dial In User Service (RADIUS)
 description:         This module provides types and on the wire de/coding of RADIUS packets as per RFC2865
 homepage:            https://github.com/erickg/radius#readme
@@ -20,6 +20,7 @@
   build-depends:       base >= 4.7 && < 5
                      , binary
                      , bytestring
+                     , cryptohash-md5
                      , iproute
                      , pretty-hex
   default-language:    Haskell2010
diff --git a/src/Network/RADIUS/Encoding.hs b/src/Network/RADIUS/Encoding.hs
--- a/src/Network/RADIUS/Encoding.hs
+++ b/src/Network/RADIUS/Encoding.hs
@@ -18,14 +18,15 @@
 import Control.Monad               (when)
 import Data.Binary                 (Binary(..), encode)
 import Data.Binary.Put             (Put, putLazyByteString, putWord8, putWord16be, putWord32be)
-import Data.Binary.Get             (Get, getLazyByteString, getWord8, getWord16be, isEmpty)
-import Data.ByteString.Lazy.Char8  (ByteString)
+import Data.Binary.Get             (Get, getLazyByteString, getWord8, getWord16be, getWord32be, isEmpty)
+import Data.ByteString.Lazy.Char8  (ByteString, append)
 import Data.IP                     (IPv4, IPv6)
 import Data.Int                    (Int64)
-import Data.Word                   (Word8, Word16, Word32)
+import Data.Word                   (Word8, Word16)
 import Network.RADIUS.Types
 
 import qualified Data.ByteString.Lazy.Char8 as B
+import qualified Crypto.Hash.MD5            as MD5
 
 -- | Self explanatory. It can be useful when reading a RADIUS packet from a socket for example,
 -- so one can retrieve the packet header (containing the packet length) first and then use that
@@ -74,9 +75,16 @@
   return Packet { getHeader           = header,
                   getPacketAttributes = attributes }
 
+sign :: ByteString -> ByteString -> ByteString
+sign packet secret =
+    let authenticator = B.fromStrict . MD5.hashlazy $ packet `append` secret
+        prologue      = B.take 4 packet -- size of type, id, length
+        attributes    = B.drop (fromIntegral radiusHeaderSize) packet
+    in prologue `append` authenticator `append` attributes
+
 instance Binary PacketType where
-    put = putEnum
-    get = getEnum
+    put = putWord8 . fromIntegral . fromEnum
+    get = getWord8 >>= return . toEnum . fromIntegral
 
 -- | Used internally to encode a list of RADIUS attributes. You probably don't need this.
 encodeAttributes :: [PacketAttribute] -> ByteString
@@ -243,22 +251,22 @@
 getAttribute 62 = getAttributeValue >>= return . PortLimitAttribute
 getAttribute 4  = getAttributeValue >>= return . NASIPAddress
 getAttribute 95 = getAttributeValue >>= return . NASIPv6Address
-getAttribute 6  = getAttributeValue >>= return . ServiceTypeAttribute . fromEnum32
-getAttribute 7  = getAttributeValue >>= return . FramedProtocolAttribute . fromEnum32
+getAttribute 6  = getAttributeValue >>= return . ServiceTypeAttribute
+getAttribute 7  = getAttributeValue >>= return . FramedProtocolAttribute
 getAttribute 8  = getAttributeValue >>= return . FramedIPAddressAttribute
 getAttribute 9  = getAttributeValue >>= return . FramedIPNetmaskAttribute
-getAttribute 10 = getAttributeValue >>= return . FramedRoutingAttribute . fromEnum32
-getAttribute 13 = getAttributeValue >>= return . FramedCompressionAttribute . fromEnum32
+getAttribute 10 = getAttributeValue >>= return . FramedRoutingAttribute
+getAttribute 13 = getAttributeValue >>= return . FramedCompressionAttribute
 getAttribute 96 = getAttributeValue >>= return . FramedInterfaceIdAttribute
 getAttribute 14 = getAttributeValue >>= return . LoginIPHostAttribute
 getAttribute 98 = getAttributeValue >>= return . LoginIPv6HostAttribute
-getAttribute 15 = getAttributeValue >>= return . LoginServiceAttribute . fromEnum32
-getAttribute 29 = getAttributeValue >>= return . TerminationActionAttribute . fromEnum32
-getAttribute 61 = getAttributeValue >>= return . NASPortTypeAttribute . fromEnum32
+getAttribute 15 = getAttributeValue >>= return . LoginServiceAttribute
+getAttribute 29 = getAttributeValue >>= return . TerminationActionAttribute
+getAttribute 61 = getAttributeValue >>= return . NASPortTypeAttribute
 getAttribute 52 = getAttributeValue >>= return . AccountInputGigawordsAttribute
 getAttribute 53 = getAttributeValue >>= return . AccountOutputGigawordsAttribute
 getAttribute 55 = getAttributeValue >>= return . EventTimeStampAttribute
-getAttribute 72 = getAttributeValue >>= return . ARAPZoneAccessAttribute . fromEnum32
+getAttribute 72 = getAttributeValue >>= return . ARAPZoneAccessAttribute
 getAttribute 73 = getAttributeValue >>= return . ARAPSecurityAttribute
 getAttribute 75 = getAttributeValue >>= return . PasswordRetryAttribute
 getAttribute 76 = getAttributeValue >>= return . PromptAttribute
@@ -330,8 +338,4 @@
 
 -- | For internal use.
 getEnum :: (Enum a) => Get a
-getEnum = getWord8 >>= return . toEnum . fromIntegral
-
--- | For internal use.
-fromEnum32 :: (Enum a) => Word32 -> a
-fromEnum32 = toEnum . fromIntegral
+getEnum = getWord32be >>= return . toEnum . fromIntegral
diff --git a/src/Network/RADIUS/Types.hs b/src/Network/RADIUS/Types.hs
--- a/src/Network/RADIUS/Types.hs
+++ b/src/Network/RADIUS/Types.hs
@@ -226,6 +226,7 @@
                  | SyncNASPort
                  | ISDNSyncPort
                  | ISDNAsyncV120Port
+                 | ISDNAsyncV110Port
                  | VirtualNASPort
                  | PIAFSNASPort
                  | HDLCClearChannelNASPort