DES 实现
原理
加密
置换：
IP逆置换：
迭代：
PC-1置换：
PC-2置换：
子秘钥的生成：
加密函数f：
解密
代码
// C语言实现
#include<stdio.h>
#include<string.h>
/*
参考链接：https://blog.csdn.net/zidane_2014/article/details/37988657
*/
int IP_Table[64] = { //IP置换矩阵
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 };
int E_Table[48] = { //扩展矩阵
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 };
int P_Table[32] = { // P 盒
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 };
int IPR_Table[64] = { //逆IP置换矩阵
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 };
int PC1_Table[56] = { //密钥第一次置换矩阵
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 };
int PC2_Table[48] = { // 密钥第二次置换矩阵
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 };
int S_Box[8][4][16] = { //8个S盒 三维数组
// 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 void CharToBit(const char input[], int output[], int bits)//把CHAR转换为INT
{
int i, j;
for (j = 0; j < 8; j++)
{
for (i = 0; i < 8; i++)
{
output[7 * (j + 1) - i + j] = (input[j] >> i) & 1;
}
}
};
static void BitToChar(const int intput[], char output[], int bits)//把INT转换为CHAR
{
int i, j;
for (j = 0; j < 8; j++)
{
for (i = 0; i < 8; i++)
{
output[j] = output[j] * 2 + intput[i + 8 * j];
}
}
};
static void Xor(int* INA, int* INB, int len)//异或操作
{
int i;
for (i = 0; i < len; i++)
{
*(INA + i) = *(INA + i) ^ *(INB + i);
}
};
static void IP(const int input[64], int output[64], int table[64])//初始IP置换
{
int i;
for (i = 0; i < 64; i++)
{
output[i] = input[table[i] - 1];//减1操作不可少！！
}
};
static void E(const int input[32], int output[48], int table[48])//E扩展
{
int i;
for (i = 0; i < 48; i++)
{
output[i] = input[table[i] - 1];
}
};
static void P(const int input[32], int output[32], int table[32])//P置换
{
int i;
for (i = 0; i < 32; i++)
{
output[i] = input[table[i] - 1];
}
};
static void IP_In(const int input[64], int output[64], int table[64])//逆IP
{
int i;
for (i = 0; i < 64; i++)
{
output[i] = input[table[i] - 1];
}
};
static void PC_1(const int input[64], int output[56], int table[56])//PC_1
{
int i;
for (i = 0; i < 56; i++)
{
output[i] = input[table[i] - 1];
}
};
static void PC_2(const int input[56], int output[48], int table[48])//PC_2
{
int i;
for (i = 0; i < 48; i++)
{
output[i] = input[table[i] - 1];
}
};
static void S(const int input[48], int output[32], int table[8][4][16])//S盒压缩
{
int i = 0;
int j = 0;
int INT[8];
for (; i < 48; i = i + 6)
{
INT[j] = table[j][(input[i] << 1) + (input[i + 5])][(input[i + 1] << 3) + (input[i + 2] << 2) + (input[i + 3] << 1) + (input[i + 4])];
j++;
}
for (j = 0; j < 8; j++)
{
for (i = 0; i < 4; i++)
{
output[3 * (j + 1) - i + j] = (INT[j] >> i) & 1;
}
}
};
static void F_func(int input[32], int output[32], int subkey[48])//完成DES算法轮变换
{
int len = 48;
int temp[48] = { 0 };
int temp_1[32] = { 0 };
E(input, temp, E_Table);
Xor(temp, subkey, len);
S(temp, temp_1, S_Box);
P(temp_1, output, P_Table);
};
static void RotateL(const int input[28], int output[28], int leftCount)//完成子密钥扩展的循环左移
{
int i;
int len = 28;
for (i = 0; i < len; i++)
{
output[i] = input[(i + leftCount) % len];
}
};
static void subKey_fun(const int input[64], int Subkey[16][48])//完成16轮子密钥生成
{
int loop = 1, loop_2 = 2;
int i, j;
int c[28], d[28];
int pc_1[56] = { 0 };
int pc_2[16][56] = { 0 };
int rotatel_c[16][28] = { 0 };
int rotatel_d[16][28] = { 0 };
PC_1(input, pc_1, PC1_Table);
for (i = 0; i < 28; i++)
{
c[i] = pc_1[i];
d[i] = pc_1[i + 28];
}
int leftCount = 0;
for (i = 1; i < 17; i++)
{
if (i == 1 || i == 2 || i == 9 || i == 16)
{
leftCount += loop;
RotateL(c, rotatel_c[i - 1], leftCount);
RotateL(d, rotatel_d[i - 1], leftCount);
}
else
{
leftCount += loop_2;
RotateL(c, rotatel_c[i - 1], leftCount);
RotateL(d, rotatel_d[i - 1], leftCount);
}
}
for (i = 0; i < 16; i++)
{
for (j = 0; j < 28; j++)
{
pc_2[i][j] = rotatel_c[i][j];
pc_2[i][j + 28] = rotatel_d[i][j];
}
}
for (i = 0; i < 16; i++)
{
PC_2(pc_2[i], Subkey[i], PC2_Table);
}
};
//DES加密运算
static void DES_Efun(char input[8], char key_in[8], int output[64])
{
int Ip[64] = { 0 };//存储初始置换后的矩阵
int output_1[64] = { 0 };
int subkeys[16][48];
int chartobit[64] = { 0 };
int key[64];
int l[17][32], r[17][32];
CharToBit(input, chartobit, 8);//正确,转换为64个二进制数的操作正确！
IP(chartobit, Ip, IP_Table);//正确，IP初始置换！
CharToBit(key_in, key, 8);//正确！
subKey_fun(key, subkeys);//正确！
for (int i = 0; i < 32; i++)
{
l[0][i] = Ip[i];
r[0][i] = Ip[32 + i];
}
for (int j = 1; j < 16; j++)//前15轮的操作
{
for (int k = 0; k < 32; k++)
{
l[j][k] = r[j - 1][k];
}
F_func(r[j - 1], r[j], subkeys[j - 1]);
Xor(r[j], l[j - 1], 32);
}
int t = 0;
for (t = 0; t < 32; t++)//最后一轮的操作
{
r[16][t] = r[15][t];
}
F_func(r[15], l[16], subkeys[15]);
Xor(l[16], l[15], 32);
for (t = 0; t < 32; t++)
{
output_1[t] = l[16][t];
output_1[32 + t] = r[16][t];
}
IP_In(output_1, output, IPR_Table);
};
//完成DES解密运算
static void DES_Dfun(int input[64], char key_in[8], char output[8])
{
int Ip[64] = { 0 };//存储初始置换后的矩阵
int output_1[64] = { 0 };
int output_2[64] = { 0 };
int subkeys[16][48];
int chartobit[64] = { 0 };
int key[64];
int l[17][32], r[17][32];
IP(input, Ip, IP_Table);//正确，IP初始置换！
CharToBit(key_in, key, 8);//正确！
subKey_fun(key, subkeys);//正确！
for (int i = 0; i < 32; i++)
{
l[0][i] = Ip[i];
r[0][i] = Ip[32 + i];
}
for (int j = 1; j < 16; j++)//前15轮的操作
{
for (int k = 0; k < 32; k++)
{
l[j][k] = r[j - 1][k];
}
F_func(r[j - 1], r[j], subkeys[16 - j]);
Xor(r[j], l[j - 1], 32);
}
int t = 0;
for (t = 0; t < 32; t++)//最后一轮的操作
{
r[16][t] = r[15][t];
}
F_func(r[15], l[16], subkeys[0]);
Xor(l[16], l[15], 32);
for (t = 0; t < 32; t++)
{
output_1[t] = l[16][t];
output_1[32 + t] = r[16][t];
}
IP_In(output_1, output_2, IPR_Table);
BitToChar(output_2, output, 8);
};
int main()
{
int output[64] = { 0 };
char MIN[9] = { 0 }; // 明文
char MI[9] = { 0 }; //秘钥
printf("请输入明文（8个字符）：");
gets(MIN);
printf("请输入秘钥（8个字符）：");
gets(MI);
DES_Efun(MIN, MI, output);
printf("密文如下:\n");
for (int i = 0; i < 64; i++)
{
printf("%d", output[i]);
if ((i + 1) % 4 == 0)
printf("\n");
}
printf("\n");
printf("解密功能\n");
DES_Dfun(output, MI, MIN);
printf("明文如下:\n");
for (int i = 0; i < 8; i++)
{
printf("%c", MIN[i]);
}
printf("\n");
system("pause");
return 0;
}
