diff --git a/Data/X509/Ext.hs b/Data/X509/Ext.hs
--- a/Data/X509/Ext.hs
+++ b/Data/X509/Ext.hs
@@ -8,7 +8,7 @@
 -- extension processing module.
 --
 {-# LANGUAGE FlexibleContexts #-}
-
+{-# LANGUAGE ScopedTypeVariables #-}
 module Data.X509.Ext
     ( Extension(..)
     -- * Common extension usually found in x509v3
@@ -21,6 +21,7 @@
     , ExtSubjectAltName(..)
     , ExtAuthorityKeyId(..)
     , ExtCrlDistributionPoints(..)
+    , ExtNetscapeComment(..)
     , AltName(..)
     , DistributionPoint(..)
     , ReasonFlag(..)
@@ -35,11 +36,15 @@
 import qualified Data.ByteString.Char8 as BC
 import Data.ASN1.Types
 import Data.ASN1.Parse
+import Data.ASN1.Encoding
+import Data.ASN1.BinaryEncoding
 import Data.ASN1.BitArray
+import Data.Proxy
 import Data.List (find)
 import Data.X509.ExtensionRaw
 import Data.X509.DistinguishedName
 import Control.Applicative
+import Control.Monad
 
 -- | key usage flag that is found in the key usage extension field.
 data ExtKeyUsageFlag =
@@ -65,11 +70,24 @@
 --
 -- each extension have a unique OID associated, and a way
 -- to encode and decode an ASN1 stream.
+--
+-- Errata: turns out, the content is not necessarily ASN1,
+-- it could be data that is only parsable by the extension
+-- e.g. raw ascii string. Add method to parse and encode with
+-- ByteString
 class Extension a where
-    extOID    :: a -> OID
-    extEncode :: a -> [ASN1]
-    extDecode :: [ASN1] -> Either String a
+    extOID           :: a -> OID
+    extHasNestedASN1 :: Proxy a -> Bool
+    extEncode        :: a -> [ASN1]
+    extDecode        :: [ASN1] -> Either String a
 
+    extDecodeBs :: B.ByteString -> Either String a
+    extDecodeBs = (either (Left . show) Right . decodeASN1' BER) >=> extDecode
+
+    extEncodeBs :: a -> B.ByteString
+    extEncodeBs = encodeASN1' DER . extEncode
+
+
 -- | Get a specific extension from a lists of raw extensions
 extensionGet :: Extension a => Extensions -> Maybe a
 extensionGet (Extensions Nothing)  = Nothing
@@ -94,16 +112,17 @@
 -- * Nothing, the OID doesn't match
 -- * Just Left, the OID matched, but the extension couldn't be decoded
 -- * Just Right, the OID matched, and the extension has been succesfully decoded
-extensionDecode :: Extension a => ExtensionRaw -> Maybe (Either String a)
-extensionDecode = doDecode undefined
-  where doDecode :: Extension a => a -> ExtensionRaw -> Maybe (Either String a)
-        doDecode dummy (ExtensionRaw oid _ asn1)
-            | extOID dummy == oid = Just (extDecode asn1)
-            | otherwise           = Nothing
+extensionDecode :: forall a . Extension a => ExtensionRaw -> Maybe (Either String a)
+extensionDecode er@(ExtensionRaw oid _ content)
+    | extOID (undefined :: a) /= oid      = Nothing
+    | extHasNestedASN1 (Proxy :: Proxy a) = Just (tryExtRawASN1 er >>= extDecode)
+    | otherwise                           = Just (extDecodeBs content)
 
 -- | Encode an Extension to extensionRaw
-extensionEncode :: Extension a => Bool -> a -> ExtensionRaw
-extensionEncode critical ext = ExtensionRaw (extOID ext) critical (extEncode ext)
+extensionEncode :: forall a . Extension a => Bool -> a -> ExtensionRaw
+extensionEncode critical ext
+    | extHasNestedASN1 (Proxy :: Proxy a) = ExtensionRaw (extOID ext) critical (encodeASN1' DER $ extEncode ext)
+    | otherwise                           = ExtensionRaw (extOID ext) critical (extEncodeBs ext)
 
 -- | Basic Constraints
 data ExtBasicConstraints = ExtBasicConstraints Bool (Maybe Integer)
@@ -111,6 +130,7 @@
 
 instance Extension ExtBasicConstraints where
     extOID = const [2,5,29,19]
+    extHasNestedASN1 = const True
     extEncode (ExtBasicConstraints b Nothing)  = [Start Sequence,Boolean b,End Sequence]
     extEncode (ExtBasicConstraints b (Just i)) = [Start Sequence,Boolean b,IntVal i,End Sequence]
 
@@ -127,6 +147,7 @@
 
 instance Extension ExtKeyUsage where
     extOID = const [2,5,29,15]
+    extHasNestedASN1 = const True
     extEncode (ExtKeyUsage flags) = [BitString $ flagsToBits flags]
     extDecode [BitString bits] = Right $ ExtKeyUsage $ bitsToFlags bits
     extDecode _ = Left "unknown sequence"
@@ -158,6 +179,7 @@
 
 instance Extension ExtExtendedKeyUsage where
     extOID = const [2,5,29,37]
+    extHasNestedASN1 = const True
     extEncode (ExtExtendedKeyUsage purposes) =
         [Start Sequence] ++ map (OID . lookupRev) purposes ++ [End Sequence]
       where lookupRev (KeyUsagePurpose_Unknown oid) = oid
@@ -174,6 +196,7 @@
 
 instance Extension ExtSubjectKeyId where
     extOID = const [2,5,29,14]
+    extHasNestedASN1 = const True
     extEncode (ExtSubjectKeyId o) = [OctetString o]
     extDecode [OctetString o] = Right $ ExtSubjectKeyId o
     extDecode _ = Left "unknown sequence"
@@ -203,6 +226,7 @@
 
 instance Extension ExtSubjectAltName where
     extOID = const [2,5,29,17]
+    extHasNestedASN1 = const True
     extEncode (ExtSubjectAltName names) = encodeGeneralNames names
     extDecode l = runParseASN1 (ExtSubjectAltName <$> parseGeneralNames) l
 
@@ -213,6 +237,7 @@
 
 instance Extension ExtAuthorityKeyId where
     extOID _ = [2,5,29,35]
+    extHasNestedASN1 = const True
     extEncode (ExtAuthorityKeyId keyid) =
         [Start Sequence,Other Context 0 keyid,End Sequence]
     extDecode [Start Sequence,Other Context 0 keyid,End Sequence] =
@@ -244,6 +269,7 @@
 
 instance Extension ExtCrlDistributionPoints where
     extOID _ = [2,5,29,31]
+    extHasNestedASN1 = const True
     extEncode = error "extEncode ExtCrlDistributionPoints unimplemented"
     extDecode = error "extDecode ExtCrlDistributionPoints unimplemented"
     --extEncode (ExtCrlDistributionPoints )
@@ -311,3 +337,14 @@
 flagsToBits :: Enum a => [a] -> BitArray
 flagsToBits flags = foldl bitArraySetBit bitArrayEmpty $ map (fromIntegral . fromEnum) flags
   where bitArrayEmpty = toBitArray (B.pack [0,0]) 7
+
+data ExtNetscapeComment = ExtNetscapeComment B.ByteString
+    deriving (Show,Eq)
+
+instance Extension ExtNetscapeComment where
+    extOID _ = [2,16,840,1,113730,1,13]
+    extHasNestedASN1 = const False
+    extEncode = error "Extension: Netscape Comment do not contain nested ASN1"
+    extDecode = error "Extension: Netscape Comment do not contain nested ASN1"
+    extEncodeBs (ExtNetscapeComment b) = b
+    extDecodeBs = Right . ExtNetscapeComment
diff --git a/Data/X509/ExtensionRaw.hs b/Data/X509/ExtensionRaw.hs
--- a/Data/X509/ExtensionRaw.hs
+++ b/Data/X509/ExtensionRaw.hs
@@ -9,6 +9,8 @@
 --
 module Data.X509.ExtensionRaw
     ( ExtensionRaw(..)
+    , tryExtRawASN1
+    , extRawASN1
     , Extensions(..)
     ) where
 
@@ -17,14 +19,25 @@
 import Data.ASN1.Encoding
 import Data.ASN1.BinaryEncoding
 import Data.X509.Internal
+import qualified Data.ByteString as B
 
 -- | An undecoded extension
 data ExtensionRaw = ExtensionRaw
     { extRawOID      :: OID    -- ^ OID of this extension
     , extRawCritical :: Bool   -- ^ if this extension is critical
-    , extRawASN1     :: [ASN1] -- ^ the associated ASN1
+    , extRawContent  :: B.ByteString -- ^ undecoded content
     } deriving (Show,Eq)
 
+tryExtRawASN1 :: ExtensionRaw -> Either String [ASN1]
+tryExtRawASN1 (ExtensionRaw oid _ content) =
+    case decodeASN1' BER content of
+        Left err -> Left $ "fromASN1: X509.ExtensionRaw: OID=" ++ show oid ++ ": cannot decode data: " ++ show err
+        Right r  -> Right r
+
+extRawASN1 :: ExtensionRaw -> [ASN1]
+extRawASN1 extRaw = either error id $ tryExtRawASN1 extRaw
+{-# DEPRECATED extRawASN1 "use tryExtRawASN1 instead" #-}
+
 -- | a Set of 'ExtensionRaw'
 newtype Extensions = Extensions (Maybe [ExtensionRaw])
     deriving (Show,Eq)
@@ -41,19 +54,12 @@
     toASN1 extraw = \xs -> encodeExt extraw ++ xs
     fromASN1 (Start Sequence:OID oid:xs) =
         case xs of
-            Boolean b:OctetString obj:End Sequence:xs2 -> extractExt b obj xs2
-            OctetString obj:End Sequence:xs2           -> extractExt False obj xs2
+            Boolean b:OctetString obj:End Sequence:xs2 -> Right (ExtensionRaw oid b obj, xs2)
+            OctetString obj:End Sequence:xs2           -> Right (ExtensionRaw oid False obj, xs2)
             _                                          -> Left ("fromASN1: X509.ExtensionRaw: unknown format:" ++ show xs)
-      where
-        extractExt critical bs remainingStream =
-            case decodeASN1' BER bs of
-                Left err -> Left ("fromASN1: X509.ExtensionRaw: OID=" ++ show oid ++
-                                  ": cannot decode data: " ++ show err)
-                Right r  -> Right (ExtensionRaw oid critical r, remainingStream)
     fromASN1 l                                      =
         Left ("fromASN1: X509.ExtensionRaw: unknown format:" ++ show l)
 
 encodeExt :: ExtensionRaw -> [ASN1]
-encodeExt (ExtensionRaw oid critical asn1) =
-    let bs = encodeASN1' DER asn1
-     in asn1Container Sequence ([OID oid] ++ (if critical then [Boolean True] else []) ++ [OctetString bs])
+encodeExt (ExtensionRaw oid critical content) =
+    asn1Container Sequence ([OID oid] ++ (if critical then [Boolean True] else []) ++ [OctetString content])
diff --git a/x509.cabal b/x509.cabal
--- a/x509.cabal
+++ b/x509.cabal
@@ -1,5 +1,5 @@
 Name:                x509
-version:             1.7.0
+version:             1.7.1
 Description:         X509 reader and writer
 License:             BSD3
 License-file:        LICENSE