des.cpp

des加密算法 des加密算法 des加密算法 解密

		SReplace(r_bit[i - 1]); 

		//结果与L的上次迭代结果异或得到R的此次迭代结果 
		for(j = 0; j < 4; j++) 
		{
			r_bit[i][j] = l_bit[i-1][j] ^ r_bit[i-1][j];
		}  
	}  
	//组合最终迭代结果
	for(i = 0; i < 4; i++)
		e_bit[i] = r_bit[16][i], e_bit[i + 4] = l_bit[16][i];   

	ASCII2Bin(e_bit, e_byte); 
	//按照表IP-1进行位变换
	for(i = 0; i < 64; i++) 
		e_byte1[i] = e_byte[ip_1[i] - 1];  
	//得到最后的加密结果.  
	Bin2ASCII(e_byte1, e_bit); 
}

/* 
*   undes 函数说明： 
*     DES解密，与加密步骤完全相同，只是迭代顺序是从16到1 
*   返回： 
*     无  
*   参数：  
*     const BYTE m_bit[8] 输入的密文 
*     const BYTE k_bit[8] 输入的密钥 
*     BYTE e_bit[8] 输出解密后的原文  
*/ 
void DES::undes(const BYTE m_bit[8], const BYTE k_bit[8], BYTE e_bit[8]) 
{  
	//换位表IP
	int ip[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
	}; 
	//换位表IP_1 
	int ip_1[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 
	}; 
	//放大换位表 
	int e[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
	};
	BYTE m_bit1[8] = {0};
	BYTE m_byte[64] = {0}; 
	BYTE m_byte1[64] = {0}; 
	BYTE key_n[16][8] = {0}; 
	BYTE l_bit[17][8] = {0}; 
	BYTE r_bit[17][8] = {0};
	BYTE e_byte[64] = {0}; 
	BYTE e_byte1[64] = {0}; 
	BYTE l_byte[64] = {0}; 
	BYTE l_byte1[64] = {0}; 
	int i = 0, j = 0; 
	//根据密钥生成16个子密钥 
	GenSubKey(k_bit, key_n); 
	//将待加密字串变换成01串 
	ASCII2Bin(m_bit, m_byte); 
	//按照ip表对待加密字串进行位变换 
	for(i = 0; i < 64; i++) 
		m_byte1[i] = m_byte[ip[i] - 1];
	//位变换后的待加密字串 
	Bin2ASCII(m_byte1, m_bit1); 
	//将位变换后的待加密字串分成两组，分别为前4字节R和后4字节L，作为迭代的基础（第16次迭代） 
	for(i = 0; i < 4; i++) 
		r_bit[16][i] = m_bit1[i], l_bit[16][i] = m_bit1[i + 4]; 
	//16次迭代运算 
	for(i = 16; i > 0; i--)
	{ 
		//L的上一次的迭代结果作为R的当前次迭代结果 
		for(j = 0; j < 4; j++) 
			r_bit[i-1][j] = l_bit[i][j];

		ASCII2Bin(l_bit[i], l_byte); 
		//将L的上一次迭代结果按E表进行位扩展得到48位中间结果 
		for(j = 0; j < 48; j++)
			l_byte1[j] = l_byte[e[j] - 1]; 
		Bin2ASCII(l_byte1, l_bit[i]);

		//与第I-1个子密钥进行异或运算 
		for(j = 0; j < 6; j++) 
			l_bit[i][j] = l_bit[i][j] ^ key_n[i-1][j];

		//进行S选择，得到32位中间结果 
		SReplace(l_bit[i]); 

		//结果与R的上次迭代结果异或得到L的此次迭代结果
		for(j = 0; j < 4; j++) 
		{
			l_bit[i-1][j] = r_bit[i][j] ^ l_bit[i][j]; 
		} 
	} 
	//组合最终迭代结果 
	for(i = 0; i < 4; i++)  
		e_bit[i] = l_bit[0][i], e_bit[i + 4] = r_bit[0][i]; 

	ASCII2Bin(e_bit, e_byte);
	//按照表IP-1进行位变换
	for(i = 0; i < 64; i++) 
		e_byte1[i] = e_byte[ip_1[i] - 1]; 
	//得到最后的结果.  
	Bin2ASCII(e_byte1, e_bit);
} 

/* 
*   SReplace 函数说明： 
*     S选择 
*   返回：
*     无 
*   参数：  
*     BYTE s_bit[8] 输入暨选择后的输出 
*/ 
void DES::SReplace(BYTE s_bit[8]) 
{ 
	int p[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 
	}; 
	BYTE s[][4][16] ={ 
		{
			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 
		}, 
		{  
			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 
		},  
		{
			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
		},
		{ 
			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 
		}, 
		{
			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, 
		},
		{ 
			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 
		},
		{
			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 
		},   
		{ 
			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 
		}
	}; 
	BYTE s_byte[64] = {0}; 
	BYTE s_byte1[64] = {0};
	BYTE row = 0, col = 0;
	BYTE s_out_bit[8] = {0};

	//转成二进制字符串处理 
	ASCII2Bin(s_bit, s_byte); 
	for(i = 0; i < 8; i++) 
	{ 
		//0、5位为row，1、2、3、4位为col，在S表中选择一个八位的数 
		row = s_byte[i * 6] * 2 + s_byte[i * 6 + 5]; 
			col = s_byte[i * 6 + 1] * 8 + s_byte[i * 6 + 2] * 4 + s_byte[i * 6 + 3] * 2 + s_byte[i * 6 + 4]; 
		s_out_bit[i] = s[i][row][col];
	}
	//将八个选择的八位数据压缩表示
	s_out_bit[0] = (s_out_bit[0] << 4) + s_out_bit[1]; 
	s_out_bit[1] = (s_out_bit[2] << 4) + s_out_bit[3]; 
	s_out_bit[2] = (s_out_bit[4] << 4) + s_out_bit[5];
	s_out_bit[3] = (s_out_bit[6] << 4) + s_out_bit[7]; 
	//转成二进制字符串处理 
	ASCII2Bin(s_out_bit, s_byte); 
	//换位  
	for(i = 0; i < 32; i++) 
		s_byte1[i] = s_byte[p[i] - 1];
	//生成最后结果 
	Bin2ASCII(s_byte1, s_bit); 
}


/*
*	inputkey 输入16进制ASCII密钥转成BIN
*		in 输入ASCII
*		out 输出bin(8字节)
*/
void inputkey(char in[16], BYTE out[8])
{
	//memset(out,0,sizeof(BYTE)*8);
	int i;
	for(i=0;i<16;i+=2)
	{
		if(in[i]>='0' && in[i]<='9')
			out[i/2]=(in[i]-'0')<<4;
		else if(in[i]>='A' && in[i]<='F')
			out[i/2]=(in[i]-'A'+10)<<4;
	}
	for(i=1;i<16;i+=2)
	{
		if(in[i]>='0' && in[i]<='9')
			out[i/2]+=in[i]-'0';
		else if(in[i]>='A' && in[i]<='F')
			out[i/2]+=in[i]-'A'+10;
	}
}

/*
*	outputcipher 输入8字节转换成16char
*		in 输入8字节
*		out 输出16个char
*/
void outputcipher(BYTE in[8], char out[17])
{
	int i;
	unsigned char tmp;
	for(i=0;i<8;i++)
	{
		tmp=(0xf0 & in[i]) >> 4;
		if(tmp>=10)
			out[i*2]=tmp-10+'A';
		else
			out[i*2]=tmp+'0';
	}
	for(i=0;i<8;i++)
	{
		tmp=0x0f & in[i];
		if(tmp>=10)
			out[i*2+1]=tmp-10+'A';
		else
			out[i*2+1]=tmp+'0';
	}
}

int main()
{
	BYTE plain[100],cipher[100],key[100];
	char input_key[20],output_cipher[20],new_plain[20];
	DES des;
	printf("Input Key:");
	scanf(" %s",input_key);              //输入16个16进制数的密钥
	inputkey(input_key,key);             //输入16进制ASCII密钥转成BIN
	printf("Input PlainText:");
	scanf(" %s",plain);                  //输入8的字符的明文 
	printf("CipherText:");
	des.CDesEnter(plain,cipher,8,key,0); //调用加密函数
	outputcipher(cipher,output_cipher);  //输入8字节转换成16char
	output_cipher[16]=0;       
	printf("%s\n",output_cipher);        //输出密文
	printf("Decryption:");
	des.CDesEnter(cipher,(BYTE*)new_plain,8,key,1);//调用解密函数
	new_plain[8]=0;
	printf("%s\n",new_plain);             //输入解密后的明文
	return 0;
}