From cb4a44fdeaa6e781e1faf04087450fe4c750832a Mon Sep 17 00:00:00 2001
From: joe <joe@jerkface.net>
Date: Fri, 30 Aug 2013 17:53:28 -0400
Subject: Implementation of the Cast-128 cipher algorithm.

---
 Crypto/Cipher/SBox.hs | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 Crypto/Cipher/SBox.hs

(limited to 'Crypto/Cipher/SBox.hs')

diff --git a/Crypto/Cipher/SBox.hs b/Crypto/Cipher/SBox.hs
new file mode 100644
index 0000000..d3de077
--- /dev/null
+++ b/Crypto/Cipher/SBox.hs
@@ -0,0 +1,59 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Crypto.Cipher.SBox (SBox,(#),sbox,pbox,bytes,parseBox,parseBytes) where
+
+import Language.Haskell.TH
+import Language.Haskell.TH.Quote
+import Data.Bits
+import Data.Binary
+import Data.Char
+import Data.Word
+import Data.List
+import qualified Data.Vector.Unboxed as V
+import qualified Data.ByteString as S
+
+unsupported _ = fail "not supported."
+
+str  = QuasiQuoter { 
+        quoteExp = stringE, 
+        quotePat = unsupported, 
+        quoteDec = unsupported, 
+        quoteType = unsupported 
+       }
+sbox = str { quoteExp = sboxExp }
+pbox = sbox
+bytes = str { quoteExp = bytesExp }
+
+sboxExp st  = let w=mkName "parseBox"   in return $ AppE (VarE w) (LitE (StringL st))
+bytesExp st = let w=mkName "parseBytes" in return $ AppE (VarE w) (LitE (StringL st))
+
+type SBox = V.Vector Word32
+
+{-# INLINE (#) #-}
+(#) :: SBox -> Word8 -> Word32
+v # i = v V.! (fromIntegral i )
+
+
+parseBox :: String -> SBox
+parseBox xs = V.fromList $ (map (read . ("0x"++) {- . reverseNibbles -} ) . words $ xs :: [Word32])
+ where
+    reverseNibbles = concat .  reverse .  group2 (\a b->[a,b])
+
+    group2 f (x:y:ys) = f x y : group2 f ys
+    group2 _ _        = []
+
+parseBytes bs = S.pack . parseHex' . concat . words $ bs 
+ where
+  parseHex' bs =
+      let (dnib,ts) = splitAt 2 bs
+          parseNibble x = group2 toW8 $ map (hexDigit . ord8) x
+          hexDigit d = d - (if d>0x39 then if d<0x61 then 0x37 else 0x57 else 0x30)
+          group2 f (x:y:ys) = f x y : group2 f ys
+          group2 _ _        = []
+          toW8 a b = shift a 4 .|. b
+          ord8 c = fromIntegral . ord $ c :: Word8
+      in parseNibble dnib ++
+          if null ts
+              then []
+              else parseHex' ts
+
+
-- 
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