cpp1.cpp

这是我用c++实现的一个DES加密算法！应该可以适合那些对加密感兴趣的人看。

#include <iostream.h> 
#include <stdlib.h>  
#include <string.h> 

typedef bool (*PSubKey)[16][48];  //16个子密钥

const static char Table_IP[64] =  //初始置换IP表
{ 
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 
}; 

const static char Table_InverseIP[64] =  //初始置换的逆置换表（用于解密）
{ 
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 
}; 

static const char Table_E[48] =  //扩展置换E表
{ 
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 
}; 

const static char Table_PC1[56] = {  // 密钥初始置换 表（PC-1）
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 
}; 

const static char Table_Moveleft[16] =  //密钥每轮移动的位数
{ 
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1 
}; 

 
const static char Table_PC2[48] =  // 密钥压缩置换表 PC-2
{ 
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 
}; 


const static char Box_S[8][4][16] =  // S盒 
{ 
// 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 
}; 


const static char Table_P[32] = // P盒置换 
{ 
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 
}; 

static bool SubKey[16][48];//密钥的16轮子密钥 
static char Tmp[256], deskey[16]; 

#define ENCRYPT 0 //加密参数
#define DECRYPT 1 //解密参数


void Transform(bool *Out, bool *In, const char *Table, int len) //通用置换函数 
{ 
	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) //异或运算 
{ 
	for(int i = 0; i < len; ++ i) 
		InA[i] ^= InB[i]; 
} 


void MoveLeft(bool *In, int len, int loop) //循环左移 
{ 
	memcpy(Tmp, In, loop); 
	memcpy(In, In + loop, len - loop); 
	memcpy(In + len - loop, Tmp, loop); 
} 


void Byte2Bit(bool *Out, const char *In, int bits) //字节转换成位 
{ 
	for(int i = 0; i < bits; ++ i) 
		Out[i] = (In[i >> 3] >> (i & 7)) & 1; 
} 


void Bit2Byte(char *Out, const bool *In, int bits) //位转换字节 
{ 
	memset(Out, 0, bits >> 3); 
	for(int i = 0; i < bits; ++ i) 
		Out[i >> 3] |= In[i] << (i & 7); 
} 


void funS(bool Out[32], const bool In[48]) //S 盒置换 
{ 
	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]; 
		Byte2Bit(Out, &Box_S[i][j][k], 4); 
	} 
} 


void funF(bool In[32], const bool Ki[48]) //F 函数 
{ 
	static bool MR[48]; 
	Transform(MR, In, Table_E, 48); 
	Xor(MR, Ki, 48); 
	funS(In, MR); 
	Transform(In, In, Table_P, 32); 
} 

 
void MakeSubKey(PSubKey pSubKey, const char Key[8]) //生成子密钥
{ 
	static bool K[64], *KL = &K[0], *KR = &K[28]; 
	Byte2Bit(K, Key, 64); 
	Transform(K, K, Table_PC1, 56); 
	for(int i = 0; i < 16; ++ i) 
	{ 
		MoveLeft(KL, 28, Table_Moveleft[i]); 
		MoveLeft(KR, 28, Table_Moveleft[i]); 
		Transform((*pSubKey)[i], K, Table_PC2, 48); 
	} 
} 


void MakeKey(const char* Key, int len) //生成密钥 
{ 
	memcpy(deskey, Key, len > 8 ? 8 : len); //把八位密钥考入到deskey中
	MakeSubKey(&SubKey, &deskey[0]); 
} 

void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type) //DES加密解密
{ 
	static bool M[64], tmp[32], *Li = &M[0], *Ri = &M[32]; 
	Byte2Bit(M, In, 64); 
	Transform(M, M, Table_IP, 64); 
	if( Type == ENCRYPT )
	{ 
		for(int i = 0; i < 16; ++ i) 
		{ 
			memcpy(tmp, Ri, 32); 
			funF(Ri, (*pSubKey)[i]); 
			Xor(Ri, Li, 32); 
			memcpy(Li, tmp, 32); 
		} 
	} 
	
	else 
	{ 
		for(int i = 15; i >= 0; -- i) 
		{ 
			memcpy(tmp, Li, 32); 
			funF(Li, (*pSubKey)[i]); 
			Xor(Li, Ri, 32); 
			memcpy(Ri, tmp, 32); 
		} 
	
	} 
	
	Transform(M, M, Table_InverseIP, 64); 
	Bit2Byte(Out, M, 64); 
} 

bool DoDES(char *Out, char *In, long datalen, const char *Key, int keylen, bool Type) 
{ 
	if( !( Out && In && Key && (datalen=((datalen + (8 - 1)) & ~(8 - 1) ) ) ))
		//datalen=((datalen + (8 - 1)) & ~(8 - 1) ) )作用是把数据对齐
		return false; 
	MakeKey(Key, keylen); 
	for(long i = 0, j = datalen >> 3; i < j; ++ i, Out += 8, In += 8) 
	{
		DES(Out, In,  &SubKey, Type); 
	}
	return true; 
} 

void  main() 
{ 
	char key[255]; //密钥
	char buf[255]; //缓冲数组
	char str[255]; //要加密的字符串
	cout<<"请输入要加密的字符串: \n"; 
	cin.getline(str,255); 
	do 
	{ 
		cout<<"请输入密码(8位): \n"; 
		cin>>key; 
	} while (strlen(key) != 8); //key1为8个字符 
	
	memset(buf, 0, sizeof(buf)); //设置缓冲区为一个指定的字符
	strcpy(buf, str); 
	cout<<"\n加密前的字符串：\n"; 
	cout<<buf<<endl; 
	
	DoDES(buf, buf, sizeof(str), key, sizeof(key), ENCRYPT); 
	cout<<"\n加密后的字符串：\n"; 
	cout<<buf<<endl; 
	
	DoDES(buf, buf, sizeof(str), key, sizeof(key), DECRYPT); 
	cout<<"\n解密后的字符串：\n"; 
	cout<<buf<<endl; 
}