此篇部落格，僅此紀念國慶七天長假的折磨。。。

///DES
#include<stdio.h>
#include<string.h>
#include<string>
using namespace std;
int IP_Table[64] = {                                     //IP置換矩陣
	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] = {                                    //擴充套件矩陣
	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置換矩陣
	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] = {                               //金鑰第一次置換矩陣
	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] = {                          // 金鑰第二次置換矩陣
	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個S盒   三維陣列
											// 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轉換為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轉換為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)//異或操作
{
	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置換
{
	int i;
	for (i = 0; i<64; i++)
	{
		output[i] = input[table[i] - 1];//減1操作不可少！！
	}
};
static  void E(const int input[32], int output[48], int table[48])//E擴充套件
{
	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置換
{
	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盒壓縮
{
	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演算法輪變換
{
	int len = 48;
	int temp[48] = { 0 };
	int temp_1[32] = { 0 };
	E(input, temp, E_Table);//E擴充套件
	Xor(temp, subkey, len);//異或操作
	S(temp, temp_1, S_Box);//s盒置換
	P(temp_1, output, P_Table);//p盒置換
};
static void RotateL(const int input[28], int output[28], int leftCount)//祕鑰迴圈左移
{
	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])//子金鑰生成
{
	int loop = 1, loop_2 = 2;
	int i, j;
	int c[28], d[28];
	int pc_1[56] = { 0 };//儲存金鑰的初級置換
	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++)     //金鑰分組
	{
		c[i] = pc_1[i];
		d[i] = pc_1[i + 28];
	}
	int leftCount = 0;
	for (i = 1; i<17; i++)     //16金鑰迴圈位移
	{
		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++)     //金鑰合併
	{
		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++)//金鑰第二次置換
	{
		PC_2(pc_2[i], Subkey[i], PC2_Table);
	}
};
static void  DES_Efun(char input[8], char key_in[8], char output[64])
{
	int Ip[64] = { 0 };//儲存初始置換後的矩陣
	int output_1[64] = { 0 },output_3[64] = { 0 };
	int subkeys[16][48];//置換後的金鑰
	int chartobit[64] = { 0 };//儲存明文的二進位制
	int key[64]={0};//儲存金鑰的二進位制
	int l[17][32], r[17][32];
	CharToBit(input, chartobit, 8);//轉換為64個二進位制數的操作正確！
	IP(chartobit, Ip, IP_Table);//IP初始置換！
	CharToBit(key_in, key, 8);//正確！金鑰轉換二進位制
	subKey_fun(key, subkeys);//正確！金鑰置換
	for (int i = 0; i<32; i++)   //明文分組
	{
		l[0][i] = Ip[i];
		r[0][i] = Ip[32 + i];
	}
	for (int j = 1; j<16; j++)//前15輪的操作
	{
		for (int k = 0; k<32; k++)
		{
			l[j][k] = r[j - 1][k];
		}
		F_func(r[j - 1], r[j], subkeys[j - 1]);//DES混淆轉換操作
		Xor(r[j], l[j - 1], 32);//異或運算
	}
	int t = 0;
	for (t = 0; t<32; t++)//最後一輪的操作
	{
		r[16][t] = r[15][t];
	}
	F_func(r[15], l[16], subkeys[15]);//DES置換操作
	Xor(l[16], l[15], 32);//異或運算
	for (t = 0; t<32; t++)//合併陣列
	{
		output_1[t] = l[16][t];
		output_1[32 + t] = r[16][t];
	}
	IP_In(output_1, output_3, IPR_Table);//逆運算IP
	BitToChar(output_3, output, 8);//將位元組轉換為字元
};
static void  DES_Dfun(int input[64], char key_in[8], char output[8])//解密過程
{
	int Ip[64] = { 0 };//儲存初始置換後的矩陣
	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);//正確，IP初始置換！
	CharToBit(key_in, key, 8);//正確！
	subKey_fun(key, subkeys);//正確！
	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輪的操作
	{
		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);//異或運算
	}
	int t = 0;
	for (t = 0; t<32; t++)//最後一輪的操作
	{
		r[16][t] = r[15][t];
	}
	F_func(r[15], l[16], subkeys[0]);
	Xor(l[16], l[15], 32);//異或運算
	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()
{
	char output[8] = { 0 };//儲存密文
	int output_4[64]={0};
	char MIN[9] = { 0 };//存入明文
	char MI[9] = { 0 };//存入金鑰
	printf("請輸入明文(8位元組)\n");
	gets(MIN);
	printf("請輸入祕鑰(8位元組)\n");
	gets(MI);
	DES_Efun(MIN, MI, output);//加密操作
	printf("密文如下:\n");
    for (int i = 0; i<8; i++)
	{
		printf("%c", output[i]);
	}
	printf("\n");
	printf("解密功能\n");
	CharToBit(output,output_4,8);//字元轉換
	DES_Dfun(output_4, MI, MIN);//解密操作
	printf("明文如下:\n");
	for (int i = 0; i<8; i++)
	{
		printf("%c", MIN[i]);
	}
	printf("\n\n");
	return 0;
}