DES 加密解密

// DES.cpp : 定义控制台应用程序的入口点。
//


// DES.cpp : 定义控制台应用程序的入口点。
//


// DES.cpp : 定义控制台应用程序的入口点。
//


#include "stdafx.h"


#include "memory.h"
#include "stdio.h"
#include "string.h"
#include "stdlib.h"


enum { encrypt, decrypt };//ENCRYPT:加密，DECRYPT：解密
void des_run(char out[8], char in[8], bool type = encrypt);
//设置密钥
void des_setkey(const char key[8]);
static void f_func(bool in[32], const bool ki[48]);//f函数
static void s_func(bool out[32], const bool in[48]);//s盒代替
//变换
static void transform(bool *out, bool *in, const char *table, int len);
static void xor(bool *ina, const bool *inb, int len);//异或
static void rotatel(bool *in, int len, int loop);//循环左移
//字节组转换成位组
static void bytetobit(bool *out, const char *in, int bits);
//位组转换成字节组
static void bittobyte(char *out, const bool *in, int bits);
//置换IP表
const static char ip_table[64] = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8, 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 };
//逆置换IP-1表
const static char ipr_table[64] = { 40, 8, 48, 16, 56, 24, 64, 32, 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 };
//E 位选择表
static const char e_table[48] = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 };
//P换位表
const static char p_table[32] = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4, 25 };
//pc1选位表
const static char pc1_table[56] = {
57, 49, 41, 33, 25, 17, 9, 1,
58, 50, 42, 34, 26, 18, 10, 2,
59, 51, 43, 35, 27, 19, 11, 3,
60, 52, 44, 36, 63, 55, 47, 39,
31, 23, 15, 7, 62, 54, 46, 38,
30, 22, 14, 6, 61, 53, 45, 37,
29, 21, 13, 5, 28, 20, 12, 4
};
//pc2选位表
const static char pc2_table[48] = {
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
};
//左移位数表
const static char loop_table[16] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
//S盒
const static char s_box[8][4][16] = {
//s1
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,
//s2
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,
//s3
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,
//s4
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,
//s5
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,
//s6
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,
//s7
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,
//s8
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
};
static bool subkey[16][48];//16圈子密钥
void des_run(char out[8], char in[8], bool type)
{
static bool m[64], tmp[32], *li = &m[0], *ri = &m[32];
bytetobit(m, in, 64);
transform(m, m, ip_table, 64);
if (type == encrypt){
for (int i = 0; i < 16; i++){
memcpy(tmp, ri, 32);
f_func(ri, subkey[i]);
xor(ri, li, 32);
memcpy(li, tmp, 32);
}
}
else{
for (int i = 15; i >= 0; i--){
memcpy(tmp, li, 32);
f_func(li, subkey[i]);
xor(li, ri, 32);
memcpy(ri, tmp, 32);
}
}
transform(m, m, ipr_table, 64);
bittobyte(out, m, 64);
}
void des_setkey(const char key[8])
{
static bool k[64], *kl = &k[0], *kr = &k[28];
bytetobit(k, key, 64);
transform(k, k, pc1_table, 56);
for (int i = 0; i < 16; i++)
{
rotatel(kl, 28, loop_table[i]);
rotatel(kr, 28, loop_table[i]);
transform(subkey[i], k, pc2_table, 48);
}
}
void f_func(bool in[32], const bool ki[48])
{
static bool mr[48];
transform(mr, in, e_table, 48);
xor(mr, ki, 48);
s_func(in, mr);
transform(in, in, p_table, 32);
}
void s_func(bool out[32], const bool in[48])
{
for (char i = 0, j, k; i < 8; i++, in += 6, out += 4)
{
j = (in[0] << 1) + in[5];
k = (in[1] << 3) + (in[2] << 2) + (in[3] << 1) + in[4];
bytetobit(out, &s_box[i][j][k], 4);
}
}
void transform(bool *out, bool *in, const char *table, int len)
{
static bool tmp[256];
for (int i = 0; i < len; i++)
tmp[i] = in[table[i] - 1];
memcpy(out, tmp, len);
}
void xor(bool *ina, const bool *inb, int len)
{
for (int i = 0; i < len; i++)
ina[i] ^= inb[i];
}
void rotatel(bool *in, int len, int loop)
{
static bool tmp[256];
memcpy(tmp, in, loop);
memcpy(in, in + loop, len - loop);
memcpy(in + len - loop, tmp, loop);
}
void bytetobit(bool *out, const char *in, int bits)
{
for (int i = 0; i < bits; i++)
out[i] = (in[i / 8] >> (i % 8)) & 1;
}
void bittobyte(char *out, const bool *in, int bits)
{
memset(out, 0, (bits + 7) / 8);
for (int i = 0; i < bits; i++)
out[i / 8] |= in[i] << (i % 8);
}


int _tmain(int argc, _TCHAR* argv[])
{
//自定义密钥 通过此密钥可以将要加密的字符串生成加密字符串
char key[8] = { 'p', 'r', 'o', 'g', 'r', 'a', 'm' }, str[8];
puts("*****************DES***********************");
printf("\n");
printf("\n");
puts("please input your words");
gets_s(str);
printf("\n");
puts("****************************************");
des_setkey(key);
des_run(str, str, encrypt);
puts("after encrypting:");
puts(str);
printf("\n");
puts("****************************************");
puts("after decrypting:");
des_run(str, str, decrypt);
puts(str);
printf("\n");
puts("****************************************");
printf("\n");


return 0;
}