diff --git a/Asn.hs b/Asn.hs
new file mode 100644
--- /dev/null
+++ b/Asn.hs
@@ -0,0 +1,53 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE UnboxedTuples #-}
+
+module Asn
+  ( Asn(..)
+  , encode
+  , decode
+  ) where
+
+import Data.Text (Text)
+import Data.Primitive.Types (Prim)
+import Data.Word (Word32)
+import Data.Hashable (Hashable)
+import Foreign.Storable (Storable)
+import qualified Data.Aeson as AE
+import qualified Data.Scientific as SCI
+import qualified Data.Text as T
+import qualified Data.Text.Read as TR
+
+newtype Asn = Asn { getAsn :: Word32 }
+  deriving (Show,Read,Eq,Ord,Prim,Hashable,Storable)
+
+instance AE.ToJSON Asn where
+  toJSON = AE.String . encode
+
+instance AE.FromJSON Asn where
+  parseJSON v = case v of
+    AE.Object _ -> fail "expected ASN (String or Number), encountered Object"
+    AE.Array _ -> fail "expected ASN (String or Number), encountered Array"
+    AE.String t -> case decode t of
+      Nothing -> fail "ASN string was invalid"
+      Just w -> return w
+    AE.Number n -> case SCI.toBoundedInteger n of
+      Nothing -> fail "numeric ASN was invalid"
+      Just w -> return (Asn w)
+    AE.Bool _ -> fail "expected ASN (String or Number), encountered Bool"
+    AE.Null -> fail "expected ASN (String or Number), encountered Null"
+
+encode :: Asn -> Text
+encode (Asn w) = T.pack (show w)
+
+decode :: Text -> Maybe Asn
+decode t
+  | T.take 2 t == "AS" = decodeAsnDigits (T.drop 2 t)
+  | otherwise = decodeAsnDigits t
+
+decodeAsnDigits :: Text -> Maybe Asn
+decodeAsnDigits t = case TR.decimal t of
+  Left _ -> Nothing
+  Right (w,extra) -> if T.null extra
+    then Just (Asn w)
+    else Nothing
diff --git a/ChangeLog.md b/ChangeLog.md
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--- /dev/null
+++ b/ChangeLog.md
@@ -0,0 +1,5 @@
+# Revision history for asn
+
+## 0.1.0.0  -- YYYY-mm-dd
+
+* First version. Released on an unsuspecting world.
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2018, Andrew Martin
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Andrew Martin nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/asn.cabal b/asn.cabal
new file mode 100644
--- /dev/null
+++ b/asn.cabal
@@ -0,0 +1,25 @@
+name:                asn
+version:             0.1.0.0
+synopsis:            asn type and encoding/decoding
+description:         asn type and encoding/decoding api
+homepage:            https://github.com/chessai/asn.git
+license:             BSD3
+license-file:        LICENSE
+author:              Andrew Martin
+maintainer:          chessai <chessai1996@gmail.com>
+copyright:           Copyright (C) 2018 Layer 3 Communications, Andrew Martin       
+category:            Data
+build-type:          Simple
+extra-source-files:  ChangeLog.md
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     Asn
+  build-depends:
+      base >=4.7 && < 5.0
+    , aeson
+    , hashable
+    , primitive
+    , scientific
+    , text
+  default-language:    Haskell2010