#include <cstdio>
#include <cstring>
// IP 初始置换表
const int 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
};
// E 扩展表
const int 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 盒
const int 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
};
// IP逆置换表
const int 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
};
// 密钥第一次置换表
const int 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
};
// 密钥第二次置换表
const int 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
};
// S盒
const int 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
};
/*
* 类型转换函数 I
* 将 char 型转化为二进制形式
* 8 * sizeof(char) = 8(位) 8 个字符 64 位
*/
void CharToBit(const char input[], int output[], int bits)
{
for (int j = 0; j < 8; j++)
{
for (int i = 0; i < 8; i++)
{
output[7 * (j + 1) - i + j] = (input[j] >> i) & 1;
}
}
}
/*
* 类型转换函数 II
* 将二进制形式转化为 char 型
*/
void BitToChar(const int intput[], char output[], int bits)
{
for (int j = 0; j < 8; j++)
{
for (int i = 0; i < 8; i++)
{
output[j] = output[j] * 2 + intput[i + 8 * j];
}
}
}
/*
* 异或函数
* 将数组 INA 和 INB 进行异或操作，并且保存在 INA 中
*/
void Xor(int *INA, int *INB, int len)
{
for (int i = 0; i<len; i++)
{
*(INA + i) = *(INA + i) ^ *(INB + i);
}
}
/*
* IP 初始置换函数
* IP 根据 IP 初始置换表进行初始置换
*/
void IP_Init_Rep(const int input[64], int output[64], const int table[64])
{
for (int i = 0; i < 64; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* E 扩展置换函数
* 根据 E 扩展表进行扩展
*/
void E_Extend(const int input[32], int output[48], const int table[48])
{
for (int i = 0; i < 48; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* P 置换函数
* 根据 P 盒进行置换
*/
void P_Rep(int input[32], int output[32], const int table[32])
{
for (int i = 0; i < 32; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* IP 逆置换函数
* IP 根据 IP 逆置换表进行置换
*/
void IP_Inv_Rep(int input[64], int output[64], const int table[64])
{
for (int i = 0; i < 64; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* 密匙第一次置换函数
* 根据密匙第一次置换表进行置换
*/
void PC_1(int input[64], int output[56], const int table[56])
{
for (int i = 0; i < 56; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* 密匙第二次置换函数
* 根据密匙第二次置换表进行置换
*/
void PC_2(int input[56], int output[48], const int table[48])
{
for (int i = 0; i < 48; i++)
{
output[i] = input[table[i] - 1];
}
}
/*
* S 盒压缩函数
* 根据 8 个 S 盒进行压缩
*/
void S_Comp(int input[48], int output[32], const int table[8][4][16])
{
int INT[8];
for (int i = 0, j = 0; 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 (int j = 0; j < 8; j++)
{
for (int i = 0; i < 4; i++)
{
output[3 * (j + 1) - i + j] = (INT[j] >> i) & 1;
}
}
}
/*
* 轮迭代函数
* DES 核心迭代部分
*/
static void F_func(int input[32], int output[32], int subKey[48])
{
int len = 48;
int temp0[48] = {0};
int temp1[32] = {0};
E_Extend(input, temp0, E_Table);
Xor(temp0, subKey, len);
S_Comp(temp0, temp1, S_Box);
P_Rep(temp1, output, P_Table);
};
/*
* 密匙循环左移函数
* 密匙在不同轮数都要进行不同的左移操作
*/
void RotateL(int input[28], int output[28], int leftCount)
{
int len = 28;
for (int i = 0; i < len; i++)
{
output[i] = input[(i + leftCount) % len];
}
}
/*
* 子密匙生成函数
* 生成 subKey，在第 1、2、9、16 轮循环左移 1 位，其他轮循环左移 2 位
*/
void subKey_fun(int input[64], int Subkey[16][48])
{
int loop0 = 1, loop1 = 2;
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 (int i = 0; i < 28; i++)
{
c[i] = pc_1[i];
d[i] = pc_1[i + 28];
}
int leftCount = 0;
for (int i = 1; i < 17; i++)
{
if (i == 1 || i == 2 || i == 9 || i == 16)
{
leftCount += loop0;
RotateL(c, rotatel_c[i - 1], leftCount);
RotateL(d, rotatel_d[i - 1], leftCount);
}
else
{
leftCount += loop1;
RotateL(c, rotatel_c[i - 1], leftCount);
RotateL(d, rotatel_d[i - 1], leftCount);
}
}
for (int i = 0; i < 16; i++)
{
for (int j = 0; j < 28; j++)
{
pc_2[i][j] = rotatel_c[i][j];
pc_2[i][j + 28] = rotatel_d[i][j];
}
}
for (int i = 0; i < 16; i++)
{
PC_2(pc_2[i], Subkey[i], PC2_Table);
}
}
/*
* DES 加密函数
* 传入明文 input 和密匙 inKey，获取 64 位二进制密文 output
*/
void DES_Efun(char input[8], char inKey[8], int output[64])
{
int ip[64] = {0};
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);
IP_Init_Rep(chartobit, ip, IP_Table);
CharToBit(inKey, key, 8);
subKey_fun(key, subKeys);
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++) // 15 轮迭代
{
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++) // 第 16 轮迭代
{
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_Inv_Rep(output_1, output, IPR_Table);
}
/*
* DES 解密函数
* 传入 64 位二进制密文 input 和密匙 inKey 获取明文 output
*/
void DES_Dfun(int input[64], char inKey[8], char output[8])
{
int ip[64] = {0};
int output_1[64] = {0};
int output_2[64] = {0};
int subKeys[16][48];
int key[64];
int l[17][32], r[17][32];
IP_Init_Rep(input, ip, IP_Table);
CharToBit(inKey, key, 8);
subKey_fun(key, subKeys);
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++) // 15 轮迭代
{
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++) // 第 16 轮迭代
{
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_Inv_Rep(output_1, output_2, IPR_Table);
BitToChar(output_2, output, 8);
}
int output[64] = {0};
char A[9] = {0};
char B[9] = {0};
int main()
{
printf("Please enter the plaintext(8 bytes):\n");
scanf("%s", A);
printf("Please enter the key(8 bytes):\n");
scanf("%s", B);
DES_Efun(A, B, output);
putchar(10);
printf("Encryption\n");
for (int i = 0; i < 64; i++)
{
printf("%d", output[i]);
if ((i + 1) % 8 == 0)
{
putchar(10);
}
else if ((i + 1) % 4 == 0)
{
putchar(' ');
}
}
putchar(10);
printf("Decryption\n");
DES_Dfun(output, B, A);
for (int i = 0; i < 8; i++)
{
printf("%c", A[i]);
}
putchar(10);
return 0;
}
