diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2013, Yusuke Nomura
+
+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 Yusuke Nomura 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/Network/HTTP/Rest/Signature/EC2.hs b/Network/HTTP/Rest/Signature/EC2.hs
new file mode 100644
--- /dev/null
+++ b/Network/HTTP/Rest/Signature/EC2.hs
@@ -0,0 +1,101 @@
+module Network.HTTP.Rest.Signature.EC2
+    ( -- * Types
+      QueryString
+    , Method
+    , Endpoint
+    , Path
+    , SecretKey
+    , SignatureMethod(..)
+      -- * Building signature
+    , toString
+    , queryString
+    , queryStringFromMap
+    , stringToSign
+    , stringToSign'
+    , signature
+    , signature'
+    ) where
+
+import Data.ByteString (ByteString)
+import qualified Data.ByteString as BS
+import Data.ByteString.Char8 ()
+import qualified Data.ByteString.Lazy as BL
+import qualified Data.ByteString.Base64 as Base64
+import qualified Data.Digest.Pure.SHA as SHA
+import Data.List
+import Data.Map (Map)
+import qualified Data.Map as Map
+import Data.Monoid
+import qualified Network.HTTP.Types as HTTP
+
+-- | A query string for HTTP.
+--
+-- > "param1=value1&param2=value2"
+data QueryString = QueryString { toString :: ByteString }
+  deriving (Eq)
+
+type Method = ByteString
+type Endpoint = ByteString
+type Path = ByteString
+type SecretKey = ByteString
+data SignatureMethod = HmacSHA256
+
+-- | Convert a parameter list to 'QueryString'.
+--
+-- ex:
+--
+-- > queryString [("param1", "value1"), ("param2", "value2)] --> "param1=value1&param2=value2"
+queryString :: [(ByteString, ByteString)] -> QueryString
+queryString = queryString' . sort
+
+-- | Convert a parameter map to 'QueryString'.
+queryStringFromMap :: Map ByteString ByteString -> QueryString
+queryStringFromMap = queryString' . Map.toList
+
+queryString' :: [(ByteString, ByteString)] -> QueryString
+queryString' = QueryString . BS.intercalate "&" . map concatWithEqual
+  where
+    concatWithEqual (key, val) = mconcat
+        [ key
+        , "="
+        , HTTP.urlEncode True val
+        ]
+
+-- | Make a string for making signature.
+--
+-- ex:
+--
+-- > GET
+-- > ec2.amazonaws.com
+-- > /
+-- > Action=DescribeInstances&AWSAccessKeyId=xxx&...
+stringToSign :: Method -> Endpoint -> Path -> [(ByteString, ByteString)] -> ByteString
+stringToSign method end path = stringToSign' method end path . queryString
+
+stringToSign' :: Method -> Endpoint -> Path -> QueryString -> ByteString
+stringToSign' method end path params = BS.intercalate "\n"
+    [ method
+    , end
+    , path
+    , toString params
+    ]
+
+-- | Make signature from a parameter list.
+signature :: Method -> Endpoint -> Path -> SecretKey -> SignatureMethod -> [(ByteString, ByteString)] -> ByteString
+signature method end path secret sigm
+    = signature' method end path secret sigm . queryString
+
+-- | Make signature from a 'QueryString'.
+signature' :: Method -> Endpoint -> Path -> SecretKey -> SignatureMethod -> QueryString -> ByteString
+signature' method end path secret sigm params
+    = HTTP.urlEncode True
+    $ Base64.encode
+    $ signedString sigm
+  where
+    strToSign = stringToSign' method end path params
+    signedString HmacSHA256
+        = mconcat
+        $ BL.toChunks
+        $ SHA.bytestringDigest
+        $ SHA.hmacSha256 (toL secret) (toL strToSign)
+    toL = BL.fromChunks . (:[])
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/ec2-signature.cabal b/ec2-signature.cabal
new file mode 100644
--- /dev/null
+++ b/ec2-signature.cabal
@@ -0,0 +1,29 @@
+name:                ec2-signature
+version:             1.0
+synopsis:            The Amazon EC2 style signature calculator.
+description:         The Amazon EC2 style signature calculator.
+                     <http://docs.aws.amazon.com/general/latest/gr/signature-version-2.html>
+license:             BSD3
+license-file:        LICENSE
+author:              Yusuke Nomura<yunomu@gmail.com>
+maintainer:          Yusuke Nomura<yunomu@gmail.com>
+-- copyright:           
+homepage:            https://github.com/worksap-ate/ec2-signature
+category:            Network
+build-type:          Simple
+cabal-version:       >=1.8
+
+library
+  exposed-modules:   Network.HTTP.Rest.Signature.EC2
+  extensions:        OverloadedStrings
+  ghc-options:       -Wall -fno-warn-unused-do-bind
+  build-depends:       base == 4.*
+                     , bytestring
+                     , base64-bytestring
+                     , containers
+                     , SHA
+                     , http-types
+
+source-repository head
+    type:            git
+    location:        git://github.com/yunomu/ec2-signature.git