30分
[code="c"]
#include "stdio.h"
#define u32 unsigned long int
#define u8 unsigned char
#define DES_KEY_SIZE 8
#define DES_EXPKEY_WORDS 32
#define DES_BLOCK_SIZE 8
#define DES3_EDE_KEY_SIZE (3 * DES_KEY_SIZE)
#define DES3_EDE_EXPKEY_WORDS (3 * DES_EXPKEY_WORDS)
#define DES3_EDE_BLOCK_SIZE DES_BLOCK_SIZE
static const u32 des_keymap[] = {
0x02080008, 0x02082000, 0x00002008, 0x00000000,
0x02002000, 0x00080008, 0x02080000, 0x02082008,
0x00000008, 0x02000000, 0x00082000, 0x00002008,
0x00082008, 0x02002008, 0x02000008, 0x02080000
};
static const u8 rotors[] = {
34, 13, 5, 46, 47, 18, 32, 41, 11, 53, 33, 20,
14, 36, 30, 24, 49, 2, 15, 37, 42, 50, 0, 21,
38, 48, 6, 26, 39, 4, 52, 25, 12, 27, 31, 40,
1, 17, 28, 29, 23, 51, 35, 7, 3, 22, 9, 43
};
static const u8 parity[] = {
8,1,0,8,0,8,8,0,0,8,8,0,8,0,2,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,3,
0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,
0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0,8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,
8,0,0,8,0,8,8,0,0,8,8,0,8,0,0,8,0,8,8,0,8,0,0,8,8,0,0,8,0,8,8,0
};
static void des_small_fips_decrypt(u32 *expkey, u8 *dst, const u8 *src)
{
u32 x, y, z;
x = src[7];
x <<= 8;
x |= src[6];
x <<= 8;
x |= src[5];
x <<= 8;
x |= src[4];
y = src[3];
y <<= 8;
y |= src[2];
y <<= 8;
y |= src[1];
y <<= 8;
y |= src[0];
z = ((x >> 004) ^ y) & 0x0F0F0F0FL;
x ^= z << 004;
y ^= z;
z = ((y >> 020) ^ x) & 0x0000FFFFL;
y ^= z << 020;
x ^= z;
z = ((x >> 002) ^ y) & 0x33333333L;
x ^= z << 002;
y ^= z;
z = ((y >> 010) ^ x) & 0x00FF00FFL;
y ^= z << 010;
x ^= z;
x = x >> 1 | x << 31;
z = (x ^ y) & 0x55555555L;
y ^= z;
x ^= z;
y = y >> 1 | y << 31;
z = expkey[31];
z ^= y;
z = z << 4 | z >> 28;
x ^= * (u32 *) ((u8 *) (des_keymap + 448) + (0xFC & z));
z >>= 8;
x ^= * (u32 *) ((u8 *) (des_keymap + 384) + (0xFC & z));
z >>= 8;
x ^= * (u32 *) ((u8 *) (des_keymap + 320) + (0xFC & z));
z >>= 8;
x ^= * (u32 *) ((u8 *) (des_keymap + 256) + (0xFC & z));
z = expkey[30];
z = (x ^ y) & 0x55555555L;
y ^= z;
x ^= z;
y = y << 1 | y >> 31;
z = ((x >> 010) ^ y) & 0x00FF00FFL;
x ^= z << 010;
y ^= z;
z = ((y >> 002) ^ x) & 0x33333333L;
y ^= z << 002;
x ^= z;
z = ((x >> 020) ^ y) & 0x0000FFFFL;
x ^= z << 020;
y ^= z;
z = ((y >> 004) ^ x) & 0x0F0F0F0FL;
y ^= z << 004;
x ^= z;
dst[0] = x;
x >>= 8;
dst[1] = x;
x >>= 8;
dst[2] = x;
x >>= 8;
dst[3] = x;
dst[4] = y;
y >>= 8;
dst[5] = y;
y >>= 8;
dst[6] = y;
y >>= 8;
dst[7] = y;
}
u32 key[DES3_EDE_EXPKEY_WORDS]={
0x02030008, 0x02080608, 0x02030008,
0x02080908, 0x02080508, 0x02080908,
0x02080808, 0x02080408, 0x02080808,
0x02080708, 0x02080308, 0x02080708
};
void DE( u8 *d, u8 *s)
{
des_small_fips_decrypt(&key[DES_EXPKEY_WORDS * 2], d, s);
}
[/code]
