module Codec.Encryption.DESAux (des_enc, des_dec) where
import Data.Word
import Data.Bits
type Rotation = Int
type Key = Word64
type Message = Word64
type Enc = Word64
type BitsX = [Bool]
type Bits4 = [Bool]
type Bits6 = [Bool]
type Bits32 = [Bool]
type Bits48 = [Bool]
type Bits56 = [Bool]
type Bits64 = [Bool]
instance Num [Bool]
instance Bits [Bool] where
a `xor` b = (zipWith (\x y -> (not x && y) || (x && not y)) a b)
rotate bits rot = drop rot' bits ++ take rot' bits
where rot' = rot `mod` (length bits)
bitify :: Word64 -> Bits64
bitify w = map (\b -> w .&. (shiftL 1 b) /= 0) [63,62..0]
unbitify :: Bits64 -> Word64
unbitify bs = foldl (\i b -> if b then 1 + shiftL i 1 else shiftL i 1) 0 bs
initial_permutation :: Bits64 -> Bits64
initial_permutation mb = map ((!!) mb) i
where i = [57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7,
56, 48, 40, 32, 24, 16, 8, 0, 58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6]
key_transformation :: Bits64 -> Bits56
key_transformation kb = map ((!!) kb) i
where i = [56, 48, 40, 32, 24, 16, 8, 0, 57, 49, 41, 33, 25, 17,
9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35,
62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21,
13, 5, 60, 52, 44, 36, 28, 20, 12, 4, 27, 19, 11, 3]
des_enc :: Message -> Key -> Enc
des_enc = do_des [1,2,4,6,8,10,12,14,15,17,19,21,23,25,27,28]
des_dec :: Message -> Key -> Enc
des_dec = do_des [28,27,25,23,21,19,17,15,14,12,10,8,6,4,2,1]
do_des :: [Rotation] -> Message -> Key -> Enc
do_des rots m k = des_work rots (takeDrop 32 mb) kb
where kb = key_transformation $ bitify k
mb = initial_permutation $ bitify m
des_work :: [Rotation] -> (Bits32, Bits32) -> Bits56 -> Enc
des_work [] (ml, mr) _ = unbitify $ final_perm $ (mr ++ ml)
des_work (r:rs) mb kb = des_work rs mb' kb
where mb' = do_round r mb kb
do_round :: Rotation -> (Bits32, Bits32) -> Bits56 -> (Bits32, Bits32)
do_round r (ml, mr) kb = (mr, m')
where kb' = get_key kb r
comp_kb = compression_permutation kb'
expa_mr = expansion_permutation mr
res = comp_kb `xor` expa_mr
res' = tail $ iterate (trans 6) ([], res)
trans n (_, b) = (take n b, drop n b)
res_s = concat $ zipWith (\f (x,_) -> f x) [s_box_1, s_box_2,
s_box_3, s_box_4,
s_box_5, s_box_6,
s_box_7, s_box_8] res'
res_p = p_box res_s
m' = res_p `xor` ml
get_key :: Bits56 -> Rotation -> Bits56
get_key kb r = kb'
where (kl, kr) = takeDrop 28 kb
kb' = rotateL kl r ++ rotateL kr r
compression_permutation :: Bits56 -> Bits48
compression_permutation kb = map ((!!) kb) i
where i = [13, 16, 10, 23, 0, 4, 2, 27, 14, 5, 20, 9,
22, 18, 11, 3, 25, 7, 15, 6, 26, 19, 12, 1,
40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47,
43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31]
expansion_permutation :: Bits32 -> Bits48
expansion_permutation mb = map ((!!) mb) i
where i = [31, 0, 1, 2, 3, 4, 3, 4, 5, 6, 7, 8,
7, 8, 9, 10, 11, 12, 11, 12, 13, 14, 15, 16,
15, 16, 17, 18, 19, 20, 19, 20, 21, 22, 23, 24,
23, 24, 25, 26, 27, 28, 27, 28, 29, 30, 31, 0]
s_box :: [[Word8]] -> Bits6 -> Bits4
s_box s [a,b,c,d,e,f] = to_bool 4 $ (s !! row) !! col
where row = sum $ zipWith numericise [a,f] [1, 0]
col = sum $ zipWith numericise [b,c,d,e] [3, 2, 1, 0]
numericise = (\x y -> if x then 2^y else 0)
to_bool 0 _ = []
to_bool n i = ((i .&. 8) == 8):to_bool (n1) (shiftL i 1)
s_box_1 :: Bits6 -> Bits4
s_box_1 = s_box i
where i = [[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],
[ 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],
[ 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],
[15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]]
s_box_2 :: Bits6 -> Bits4
s_box_2 = s_box i
where i = [[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10],
[3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5],
[0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15],
[13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]]
s_box_3 :: Bits6 -> Bits4
s_box_3 = s_box i
where i = [[10, 0, 9, 14 , 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8],
[13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1],
[13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7],
[1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]]
s_box_4 :: Bits6 -> Bits4
s_box_4 = s_box i
where i = [[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15],
[13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9],
[10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4],
[3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]]
s_box_5 :: Bits6 -> Bits4
s_box_5 = s_box i
where i = [[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9],
[14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6],
[4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14],
[11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]]
s_box_6 :: Bits6 -> Bits4
s_box_6 = s_box i
where i = [[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11],
[10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8],
[9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6],
[4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]]
s_box_7 :: Bits6 -> Bits4
s_box_7 = s_box i
where i = [[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1],
[13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6],
[1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2],
[6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]]
s_box_8 :: Bits6 -> Bits4
s_box_8 = s_box i
where i = [[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7],
[1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2],
[7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8],
[2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]]
p_box :: Bits32 -> Bits32
p_box kb = map ((!!) kb) i
where i = [15, 6, 19, 20, 28, 11, 27, 16, 0, 14, 22, 25, 4, 17, 30, 9,
1, 7, 23, 13, 31, 26, 2, 8, 18, 12, 29, 5, 21, 10, 3, 24]
final_perm :: Bits64 -> Bits64
final_perm kb = map ((!!) kb) i
where i = [39, 7, 47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25, 32, 0, 40 , 8, 48, 16, 56, 24]
takeDrop :: Int -> [a] -> ([a], [a])
takeDrop _ [] = ([], [])
takeDrop 0 xs = ([], xs)
takeDrop n (x:xs) = (x:ys, zs)
where (ys, zs) = takeDrop (n1) xs