module Main where

import RSA
import System.Environment (getArgs)
import Data.Char (toLower)

main :: IO ()
main = do args <- getArgs
       	  case args of
	    ["pubkey"] -> do
	      putStrLn . hex $ e mypubkey
	      putStrLn . hex $ m mypubkey
	    ["blind"] -> do
	      r <- getLine
	      c <- getLine
	      putStrLn . hex $ blind (unhex r) (unhex c)
	    ["unblind"] -> do
	      r <- getLine
	      c <- getLine
	      putStrLn . hex $ unblind (unhex r) (unhex c)
	    ["sign"] -> do
	      x <- getLine
	      putStrLn . hex $ expMod (unhex x) (d (private mykey)) mykey
	    ["verify"] -> do
	      x <- getLine
	      putStrLn . hex $ expMod (unhex x) (e mypubkey) mykey
	    ["test"] -> do
	      r <- getLine
	      x <- getLine
	      let x' = unhex x
	      let r' = unhex r
	      let c' = blind r' x'
	      let y' = unblind r' c'
	      putStrLn $ "x = " ++ hex x'
	      putStrLn $ "r = " ++ hex r'
	      putStrLn $ "c = " ++ hex c'
	      putStrLn $ "y = " ++ hex y'
	    _  -> putStrLn "Unknown arguments"

unblind :: Integer -> Integer -> Integer
unblind r x = case modInvers r (m mypubkey) of
 	        (r':_) -> 2^2048 + blind r' x
	        _      -> error "You factorized the server key!"

blind :: Integer -> Integer -> Integer
blind r x = y
 where re = expMod r (e mypubkey) mykey
       n  = m mypubkey
       b  = x * re
       y  = b `mod` n

hexchars  = "0123456789abcdef"

unhex :: String -> Integer
unhex = foldr1 (\x s -> s*16 + x) . reverse . map unhexify
 where unhexify x = case lookup (toLower x) (zip hexchars [0..]) of
                      (Just v) -> toInteger v
		      _ -> error "Invalid number"

hex :: Integer -> String
hex 0 = "0"
hex x = map hexify . reverse . split16 $ x
 where hexify    = (hexchars !!) . fromInteger
       split16 0 = []
       split16 x = x `mod` 16 : split16 (x `div` 16)


mypubkey = public mykey
mykey = KeyPair {public = PubKey {m = 24237754553483255475536157516502463970333077002286613024097759070643491354150918169897901058642185097766538470691423514620589669362868190821316114289836212340473158025475747068812648312792239080097043228788050676207594163981964817121378570753857127852936234389027228782165681918655799356455664299342947789301740500995807880015889239515152730959319066653293077769983821774973220484062801672890431507405550594529452986795828448338149531500303084544467990934848891846404436044805231337759379482665257126132423026481865494460622947232774109126499198064882718447779415014467972606716663398469329360205104733017045718079383
      			  	 ,e = 65537}
		,private = PrivKey {d = ...
		  	    	   ,p = ...
				   ,q = ...
				   ,u = ...}}