给DES加密解密代码的步骤

unit DESCrypt;

interface
uses
SysUtils;

function EnCrypt(aStr: string; acKey: string ): string; //加密字符串-------------------------------
function DeCrypt(aStr: string; acKey: string ): string; //解密字符串-------------------------------

implementation

type
TByte32 = array[1..32] of Byte;
TSData = array[0..63] of Byte;
TBlock = array[0..7] of Byte;

const
SA1: TSData =
(1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1,
0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 0, 1);
SA2: TSData =
(1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1);
SA3: TSData =
(1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 1, 0,
1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1);
SA4: TSData =
(0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1,
1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1);
SA5: TSData =
(0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0,
0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 0);
SA6: TSData =
(1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1,
1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1);
SA7: TSData =
(0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1);
SA8: TSData =
(1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1);
SB1: TSData =
(1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0,
1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1);
SB2: TSData =
(1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1,
0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 1, 0);
SB3: TSData =
(0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0,
1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1);
SB4: TSData =
(1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0,
0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1);
SB5: TSData =
(0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1,
1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0);
SB6: TSData =
(1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0,
0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1);
SB7: TSData =
(1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1,
0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1);
SB8: TSData =
(1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0,
1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0);
SC1: TSData =
(1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0,
0, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0);
SC2: TSData =
(1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0,
0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 1, 0);
SC3: TSData =
(1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0);
SC4: TSData =
(1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0,
1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 1, 1);
SC5: TSData =
(1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1,
0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1);
SC6: TSData =
(0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0,
0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0);
SC7: TSData =
(0, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1,
0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0);
SC8: TSData =
(0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1,
1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1);
SD1: TSData =
(0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0,
0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1);
SD2: TSData =
(1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1,
0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1);
SD3: TSData =
(0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1,
1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 0);
SD4: TSData =
(1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1,
0, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0);
SD5: TSData =
(0, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0,
0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1);
SD6: TSData =
(0, 1, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0,
1, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 0, 0, 1);
SD7: TSData =
(0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0,
1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0);
SD8: TSData =
(1, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0,
1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1);

Sc: array[1..16, 1..48] of Byte =
((15, 18, 12, 25, 2, 6, 4, 1, 16, 7, 22, 11, 24, 20, 13, 5, 27, 9, 17, 8, 28, 21, 14, 3,
42, 53, 32, 38, 48, 56, 31, 41, 52, 46, 34, 49, 45, 50, 40, 29, 35, 54, 47, 43, 51, 37, 30, 33),
(16, 19, 13, 26, 3, 7, 5, 2, 17, 8, 23, 12, 25, 21, 14, 6, 28, 10, 18, 9, 1, 22, 15, 4,
43, 54, 33, 39, 49, 29, 32, 42, 53, 47, 35, 50, 46, 51, 41, 30, 36, 55, 48, 44, 52, 38, 31, 34),
(18, 21, 15, 28, 5, 9, 7, 4, 19, 10, 25, 14, 27, 23, 16, 8, 2, 12, 20, 11, 3, 24, 17, 6,
45, 56, 35, 41, 51, 31, 34, 44, 55, 49, 37, 52, 48, 53, 43, 32, 38, 29, 50, 46, 54, 40, 33, 36),
(20, 23, 17, 2, 7, 11, 9, 6, 21, 12, 27, 16, 1, 25, 18, 10, 4, 14, 22, 13, 5, 26, 19, 8,
47, 30, 37, 43, 53, 33, 36, 46, 29, 51, 39, 54, 50, 55, 45, 34, 40, 31, 52, 48, 56, 42, 35, 38),
(22, 25, 19, 4, 9, 13, 11, 8, 23, 14, 1, 18, 3, 27, 20, 12, 6, 16, 24, 15, 7, 28, 21, 10,
49, 32, 39, 45, 55, 35, 38, 48, 31, 53, 41, 56, 52, 29, 47, 36, 42, 33, 54, 50, 30, 44, 37, 40),
(24, 27, 21, 6, 11, 15, 13, 10, 25, 16, 3, 20, 5, 1, 22, 14, 8, 18, 26, 17, 9, 2, 23, 12,
51, 34, 41, 47, 29, 37, 40, 50, 33, 55, 43, 30, 54, 31, 49, 38, 44, 35, 56, 52, 32, 46, 39, 42),
(26, 1, 23, 8, 13, 17, 15, 12, 27, 18, 5, 22, 7, 3, 24, 16, 10, 20, 28, 19, 11, 4, 25, 14,
53, 36, 43, 49, 31, 39, 42, 52, 35, 29, 45, 32, 56, 33, 51, 40, 46, 37, 30, 54, 34, 48, 41, 44),
(28, 3, 25, 10, 15, 19, 17, 14, 1, 20, 7, 24, 9, 5, 26, 18, 12, 22, 2, 21, 13, 6, 27, 16,
55, 38, 45, 51, 33, 41, 44, 54, 37, 31, 47, 34, 30, 35, 53, 42, 48, 39, 32, 56, 36, 50, 43, 46),
(1, 4, 26, 11, 16, 20, 18, 15, 2, 21, 8, 25, 10, 6, 27, 19, 13, 23, 3, 22, 14, 7, 28, 17,
56, 39, 46, 52, 34, 42, 45, 55, 38, 32, 48, 35, 31, 36, 54, 43, 49, 40, 33, 29, 37, 51, 44, 47),
(3, 6, 28, 13, 18, 22, 20, 17, 4, 23, 10, 27, 12, 8, 1, 21, 15, 25, 5, 24, 16, 9, 2, 19,
30, 41, 48, 54, 36, 44, 47, 29, 40, 34, 50, 37, 33, 38, 56, 45, 51, 42, 35, 31, 39, 53, 46, 49),
(5, 8, 2, 15, 20, 24, 22, 19, 6, 25, 12, 1, 14, 10, 3, 23, 17, 27, 7, 26, 18, 11, 4, 21,
32, 43, 50, 56, 38, 46, 49, 31, 42, 36, 52, 39, 35, 40, 30, 47, 53, 44, 37, 33, 41, 55, 48, 51),
(7, 10, 4, 17, 22, 26, 24, 21, 8, 27, 14, 3, 16, 12, 5, 25, 19, 1, 9, 28, 20, 13, 6, 23,
34, 45, 52, 30, 40, 48, 51, 33, 44, 38, 54, 41, 37, 42, 32, 49, 55, 46, 39, 35, 43, 29, 50, 53),
(9, 12, 6, 19, 24, 28, 26, 23, 10, 1, 16, 5, 18, 14, 7, 27, 21, 3, 11, 2, 22, 15, 8, 25,
36, 47, 54, 32, 42, 50, 53, 35, 46, 40, 56, 43, 39, 44, 34, 51, 29, 48, 41, 37, 45, 31, 52, 55),
(11, 14, 8, 21, 26, 2, 28, 25, 12, 3, 18, 7, 20, 16, 9, 1, 23, 5, 13, 4, 24, 17, 10, 27,
38, 49, 56, 34, 44, 52, 55, 37, 48, 42, 30, 45, 41, 46, 36, 53, 31, 50, 43, 39, 47, 33, 54, 29),
(13, 16, 10, 23, 28, 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, 56, 31),
(14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32));

var
G: array[1..16, 1..48] of Byte;
L, R, F: TByte32;
C: array[1..56] of Byte;

procedure DES_Init(Key: TBlock; FCode: Boolean);
var
n, h: Byte;
begin
C[1] := Ord(Key[7] and 128 > 0); C[29] := Ord(Key[7] and 2 > 0);
C[2] := Ord(Key[6] and 128 > 0); C[30] := Ord(Key[6] and 2 > 0);
C[3] := Ord(Key[5] and 128 > 0); C[31] := Ord(Key[5] and 2 > 0);
C[4] := Ord(Key[4] and 128 > 0); C[32] := Ord(Key[4] and 2 > 0);
C[5] := Ord(Key[3] and 128 > 0); C[33] := Ord(Key[3] and 2 > 0);
C[6] := Ord(Key[2] and 128 > 0); C[34] := Ord(Key[2] and 2 > 0);
C[7] := Ord(Key[1] and 128 > 0); C[35] := Ord(Key[1] and 2 > 0);
C[8] := Ord(Key[0] and 128 > 0); C[36] := Ord(Key[0] and 2 > 0);

C[9] := Ord(Key[7] and 64 > 0); C[37] := Ord(Key[7] and 4 > 0);
C[10] := Ord(Key[6] and 64 > 0); C[38] := Ord(Key[6] and 4 > 0);
C[11] := Ord(Key[5] and 64 > 0); C[39] := Ord(Key[5] and 4 > 0);
C[12] := Ord(Key[4] and 64 > 0); C[40] := Ord(Key[4] and 4 > 0);
C[13] := Ord(Key[3] and 64 > 0); C[41] := Ord(Key[3] and 4 > 0);
C[14] := Ord(Key[2] and 64 > 0); C[42] := Ord(Key[2] and 4 > 0);
C[15] := Ord(Key[1] and 64 > 0); C[43] := Ord(Key[1] and 4 > 0);
C[16] := Ord(Key[0] and 64 > 0); C[44] := Ord(Key[0] and 4 > 0);

C[17] := Ord(Key[7] and 32 > 0); C[45] := Ord(Key[7] and 8 > 0);
C[18] := Ord(Key[6] and 32 > 0); C[46] := Ord(Key[6] and 8 > 0);
C[19] := Ord(Key[5] and 32 > 0); C[47] := Ord(Key[5] and 8 > 0);
C[20] := Ord(Key[4] and 32 > 0); C[48] := Ord(Key[4] and 8 > 0);
C[21] := Ord(Key[3] and 32 > 0); C[49] := Ord(Key[3] and 8 > 0);
C[22] := Ord(Key[2] and 32 > 0); C[50] := Ord(Key[2] and 8 > 0);
C[23] := Ord(Key[1] and 32 > 0); C[51] := Ord(Key[1] and 8 > 0);
C[24] := Ord(Key[0] and 32 > 0); C[52] := Ord(Key[0] and 8 > 0);

C[25] := Ord(Key[7] and 16 > 0); C[53] := Ord(Key[3] and 16 > 0);
C[26] := Ord(Key[6] and 16 > 0); C[54] := Ord(Key[2] and 16 > 0);
C[27] := Ord(Key[5] and 16 > 0); C[55] := Ord(Key[1] and 16 > 0);
C[28] := Ord(Key[4] and 16 > 0); C[56] := Ord(Key[0] and 16 > 0);

if FCode then
begin
for n := 1 to 16 do
begin
for h := 1 to 48 do
begin
G[n, h] := C[Sc[n, h]];
end;
end;
end
else
begin
for n := 1 to 16 do
begin
for h := 1 to 48 do
begin
G[17 - n, h] := C[Sc[n, h]];
end;
end;
end;
end;

procedure DES_Code(Input: TBlock; var Output: TBlock);
var
n: Byte;
z: Word;
begin
L[1] := Ord(Input[7] and 64 > 0); R[1] := Ord(Input[7] and 128 > 0);
L[2] := Ord(Input[6] and 64 > 0); R[2] := Ord(Input[6] and 128 > 0);
L[3] := Ord(Input[5] and 64 > 0); R[3] := Ord(Input[5] and 128 > 0);
L[4] := Ord(Input[4] and 64 > 0); R[4] := Ord(Input[4] and 128 > 0);
L[5] := Ord(Input[3] and 64 > 0); R[5] := Ord(Input[3] and 128 > 0);
L[6] := Ord(Input[2] and 64 > 0); R[6] := Ord(Input[2] and 128 > 0);
L[7] := Ord(Input[1] and 64 > 0); R[7] := Ord(Input[1] and 128 > 0);
L[8] := Ord(Input[0] and 64 > 0); R[8] := Ord(Input[0] and 128 > 0);
L[9] := Ord(Input[7] and 16 > 0); R[9] := Ord(Input[7] and 32 > 0);
L[10] := Ord(Input[6] and 16 > 0); R[10] := Ord(Input[6] and 32 > 0);
L[11] := Ord(Input[5] and 16 > 0); R[11] := Ord(Input[5] and 32 > 0);
L[12] := Ord(Input[4] and 16 > 0); R[12] := Ord(Input[4] and 32 > 0);
L[13] := Ord(Input[3] and 16 > 0); R[13] := Ord(Input[3] and 32 > 0);
L[14] := Ord(Input[2] and 16 > 0); R[14] := Ord(Input[2] and 32 > 0);
L[15] := Ord(Input[1] and 16 > 0); R[15] := Ord(Input[1] and 32 > 0);
L[16] := Ord(Input[0] and 16 > 0); R[16] := Ord(Input[0] and 32 > 0);
L[17] := Ord(Input[7] and 4 > 0); R[17] := Ord(Input[7] and 8 > 0);
L[18] := Ord(Input[6] and 4 > 0); R[18] := Ord(Input[6] and 8 > 0);
L[19] := Ord(Input[5] and 4 > 0); R[19] := Ord(Input[5] and 8 > 0);
L[20] := Ord(Input[4] and 4 > 0); R[20] := Ord(Input[4] and 8 > 0);
L[21] := Ord(Input[3] and 4 > 0); R[21] := Ord(Input[3] and 8 > 0);
L[22] := Ord(Input[2] and 4 > 0); R[22] := Ord(Input[2] and 8 > 0);
L[23] := Ord(Input[1] and 4 > 0); R[23] := Ord(Input[1] and 8 > 0);
L[24] := Ord(Input[0] and 4 > 0); R[24] := Ord(Input[0] and 8 > 0);
L[25] := Input[7] and 1; R[25] := Ord(Input[7] and 2 > 0);
L[26] := Input[6] and 1; R[26] := Ord(Input[6] and 2 > 0);
L[27] := Input[5] and 1; R[27] := Ord(Input[5] and 2 > 0);
L[28] := Input[4] and 1; R[28] := Ord(Input[4] and 2 > 0);
L[29] := Input[3] and 1; R[29] := Ord(Input[3] and 2 > 0);
L[30] := Input[2] and 1; R[30] := Ord(Input[2] and 2 > 0);
L[31] := Input[1] and 1; R[31] := Ord(Input[1] and 2 > 0);
L[32] := Input[0] and 1; R[32] := Ord(Input[0] and 2 > 0);

for n := 1 to 16 do
begin
z := ((R[32] xor G[n, 1]) shl 5) or ((R[5] xor G[n, 6]) shl 4)
or ((R[ 1] xor G[n, 2]) shl 3) or ((R[2] xor G[n, 3]) shl 2)
or ((R[ 3] xor G[n, 4]) shl 1) or ( R[4] xor G[n, 5]);
F[ 9] := L[ 9] xor SA1[z];
F[17] := L[17] xor SB1[z];
F[23] := L[23] xor SC1[z];
F[31] := L[31] xor SD1[z];

z := ((R[4] xor G[n, 7]) shl 5) or ((R[9] xor G[n, 12]) shl 4)
or ((R[5] xor G[n, 8]) shl 3) or ((R[6] xor G[n, 9]) shl 2)
or ((R[7] xor G[n, 10]) shl 1) or ( R[8] xor G[n, 11]);
F[13] := L[13] xor SA2[z];
F[28] := L[28] xor SB2[z];
F[ 2] := L[ 2] xor SC2[z];
F[18] := L[18] xor SD2[z];

z := ((R[ 8] xor G[n, 13]) shl 5) or ((R[13] xor G[n, 18]) shl 4)
or ((R[ 9] xor G[n, 14]) shl 3) or ((R[10] xor G[n, 15]) shl 2)
or ((R[11] xor G[n, 16]) shl 1) or ( R[12] xor G[n, 17]);
F[24] := L[24] xor SA3[z];
F[16] := L[16] xor SB3[z];
F[30] := L[30] xor SC3[z];
F[ 6] := L[ 6] xor SD3[z];

z := ((R[12] xor G[n, 19]) shl 5) or ((R[17] xor G[n, 24]) shl 4)
or ((R[13] xor G[n, 20]) shl 3) or ((R[14] xor G[n, 21]) shl 2)
or ((R[15] xor G[n, 22]) shl 1) or ( R[16] xor G[n, 23]);
F[26] := L[26] xor SA4[z];
F[20] := L[20] xor SB4[z];
F[10] := L[10] xor SC4[z];
F[ 1] := L[ 1] xor SD4[z];

z := ((R[16] xor G[n, 25]) shl 5) or ((R[21] xor G[n, 30]) shl 4)
or ((R[17] xor G[n, 26]) shl 3) or ((R[18] xor G[n, 27]) shl 2)
or ((R[19] xor G[n, 28]) shl 1) or ( R[20] xor G[n, 29]);
F[ 8] := L[ 8] xor SA5[z];
F[14] := L[14] xor SB5[z];
F[25] := L[25] xor SC5[z];
F[ 3] := L[ 3] xor SD5[z];

z := ((R[20] xor G[n, 31]) shl 5) or ((R[25] xor G[n, 36]) shl 4)
or ((R[21] xor G[n, 32]) shl 3) or ((R[22] xor G[n, 33]) shl 2)
or ((R[23] xor G[n, 34]) shl 1) or ( R[24] xor G[n, 35]);
F[ 4] := L[ 4] xor SA6[z];
F[29] := L[29] xor SB6[z];
F[11] := L[11] xor SC6[z];
F[19] := L[19] xor SD6[z];

z := ((R[24] xor G[n, 37]) shl 5) or ((R[29] xor G[n, 42]) shl 4)
or ((R[25] xor G[n, 38]) shl 3) or ((R[26] xor G[n, 39]) shl 2)
or ((R[27] xor G[n, 40]) shl 1) or ( R[28] xor G[n, 41]);
F[32] := L[32] xor SA7[z];
F[12] := L[12] xor SB7[z];
F[22] := L[22] xor SC7[z];
F[ 7] := L[ 7] xor SD7[z];

z := ((R[28] xor G[n, 43]) shl 5) or ((R[ 1] xor G[n, 48]) shl 4)
or ((R[29] xor G[n, 44]) shl 3) or ((R[30] xor G[n, 45]) shl 2)
or ((R[31] xor G[n, 46]) shl 1) or ( R[32] xor G[n, 47]);
F[ 5] := L[ 5] xor SA8[z];
F[27] := L[27] xor SB8[z];
F[15] := L[15] xor SC8[z];
F[21] := L[21] xor SD8[z];

L := R;
R := F;
end;

Output[0] := (L[8] shl 7) or (R[8] shl 6) or (L[16] shl 5) or (R[16] shl 4)
or (L[24] shl 3) or (R[24] shl 2) or (L[32] shl 1) or R[32];
Output[1] := (L[7] shl 7) or (R[7] shl 6) or (L[15] shl 5) or (R[15] shl 4)
or (L[23] shl 3) or (R[23] shl 2) or (L[31] shl 1) or R[31];
Output[2] := (L[6] shl 7) or (R[6] shl 6) or (L[14] shl 5) or (R[14] shl 4)
or (L[22] shl 3) or (R[22] shl 2) or (L[30] shl 1) or R[30];
Output[3] := (L[5] shl 7) or (R[5] shl 6) or (L[13] shl 5) or (R[13] shl 4)
or (L[21] shl 3) or (R[21] shl 2) or (L[29] shl 1) or R[29];
Output[4] := (L[4] shl 7) or (R[4] shl 6) or (L[12] shl 5) or (R[12] shl 4)
or (L[20] shl 3) or (R[20] shl 2) or (L[28] shl 1) or R[28];
Output[5] := (L[3] shl 7) or (R[3] shl 6) or (L[11] shl 5) or (R[11] shl 4)
or (L[19] shl 3) or (R[19] shl 2) or (L[27] shl 1) or R[27];
Output[6] := (L[2] shl 7) or (R[2] shl 6) or (L[10] shl 5) or (R[10] shl 4)
or (L[18] shl 3) or (R[18] shl 2) or (L[26] shl 1) or R[26];
Output[7] := (L[1] shl 7) or (R[1] shl 6) or (L[9] shl 5) or (R[9] shl 4)
or (L[17] shl 3) or (R[17] shl 2) or (L[25] shl 1) or R[25];
end;

function StrToKey(aKey: string): TBlock;
var
Key : TBlock;
I : Integer;
begin
FillChar(Key, SizeOf(TBlock), 0);
for I := 1 to Length(aKey) do
begin
Key[I mod SizeOf(TBlock)] := Key[I mod SizeOf(TBlock)] + Ord(aKey[I]);
end;

result := Key;
end;

function EnCrypt(aStr: string; acKey: string ): string;
var
ReadBuf : TBlock;
WriteBuf: TBlock;
Key : TBlock;
Count : Integer;
Offset : Integer;

I : Integer;
S : string;
begin
result := '';

Key := StrToKey(acKey);
Des_Init(Key, True);

Offset := 1;
Count := Length(aStr);
repeat
S := Copy(aStr, Offset, 8);
FillChar(ReadBuf, 8, 0);
Move(S[1], ReadBuf, Length(S));
Des_Code(ReadBuf, WriteBuf);

for I := 0 to 7 do
begin
result := result + IntToHex(WriteBuf[I], 2);
end;

Offset := Offset + 8;
until Offset > ((Count+7) div 8) * 8;
end;

function DeCrypt(aStr: string; acKey: string ): string;
var
ReadBuf,
WriteBuf : TBlock;
Key : TBlock;
Offset : Integer;
Count : Integer;
I : Integer;
S : string;
begin
try
Key := StrToKey(acKey);
Des_Init(Key, False);

S := '';
I := 1;
repeat
S := S + Chr(StrToInt('$'+Copy(aStr, I, 2)));
Inc(I, 2);
until I > Length(aStr);

Offset := 1;
Count := Length(S);
while Offset < ((Count+7) div 8 * 8) do
begin
FillChar(ReadBuf, 8, 0);
Move(S[Offset], ReadBuf, 8);
Des_Code(ReadBuf, WriteBuf);

for I := 0 to 7 do
begin
result := result + Chr(WriteBuf[I]);
end;

Offset := Offset + 8;
end;

result := StrPas(PChar(result));
except
result := '';
end;
end;

end.