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📄 des.h

📁 该示例演示了DES的加解密全过程,代码精简,运算速度快
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//DES算法所使用的表
///////////////////////////////////////////////////////////////////
//IP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
};
//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
};
//S_Box表
const char 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
};
//P置换表
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
};
//子密钥生产器的PC1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
};
//子密钥生产器的PC2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
};
//循环左移变换表
const char LOOP_Table[16] = {
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
//////////////////////////////////////////////////////////////////

//DES算法所使用的函数
//////////////////////////////////////////////////////////////////
//字节串转换为位串
void ByteToBit(char *Byte, bool *Bit, int len);
//位串转换为字节串
void BitToByte(bool *Bit, char *Byte, int len);
//置换函数
void Transmit(bool *In, bool *Out, const int *Table, int len);
//IP置换
void IP_Transmit(bool *Mes, bool *Cry);
//E-运算
void E_function(bool *Mes, bool *Cry);
//S-盒运算
void S_function(bool *Mes, bool *Cry);
//P置换
void P_Transmit(bool *Mes, bool *Cry);
//左右交换变换
void Swap(bool *LMes, bool *RMes);
//IP逆置换
void IPR_Transmit(bool *Mes, bool *Cry);
//中间函数f
void Function(bool *Mes, bool *Cry, bool *K);
//PC1置换函数
void PC1_Transmit(bool *Key, bool *CDkey);
//PC2置换函数
void PC2_Transmit(bool *CDkey, bool *SubKey);
//循环左移变换函数LS
void LOOP_LS(bool *CDkey, int Turn);
//子密钥生成器
void CreateSubKey(bool *Key, bool **SubKey);
//DES加密函数
void DES_Encryption(bool *Mes, bool *Key, bool *Cry);
//DES解密函数
void DES_Decryption(bool *Cry, bool *Key, bool *Mes);
//////////////////////////////////////////////////////
//DES的基本运算所需的函数
void ByteToBit(char *Byte, bool *Bit, int len)
{
	for(int i = 0; i < len; i++)
		Bit[i] = (Byte[i/8]>>(7-i%8))&1;
}
void BitToByte(bool *Bit, char *Byte, int len)
{
	for(int i = 0; i < 8; i++)
	{
		Byte[i] = 0;
		for(int j = 0; j < 8; j++)
			Byte[i] = (Byte[i]<<1)|char(Bit[j+i*8]);
	}
}
void Transmit(bool *In, bool *Out, const int *Table, int len)
{
	for(int i = 0; i < len; i++)
		Out[i] = In[Table[i] - 1];
}
void IP_Transmit(bool *Mes, bool *Cry)
{
	Transmit(Mes, Cry, IP_Table, 64);
}
void E_function(bool *Mes, bool *Cry)
{   
	for(int i = 0; i < 48; i++)
		Cry[i] = Mes[(32+i-2*(i/6)-1)%32];
}
void S_function(bool *Mes, bool *Cry)
{
	int r, l;
	int c;
	for(int i=0, s=0, j=0; s<8; i+=6, s++, j+=4)
	{
		r = Mes[i]*2 + Mes[i+5];
		l = Mes[i+1]*8 + Mes[i+2]*4 + Mes[i+3]*2 + Mes[i+4];
		c = S_Box[s][r][l];
        Cry[j] = ((c&8)>>3 ? 1:0);
		Cry[j+1] = ((c&4)>>2 ? 1:0); 
		Cry[j+2] = ((c&2)>>1 ? 1:0);
		Cry[j+3] = ((c&1) ? 1:0);
	}
}
void P_Transmit(bool *Mes, bool *Cry)
{
	Transmit(Mes, Cry, P_Table, 32);
}
void Swap(bool *LMes, bool *RMes)
{
	bool *Ptemp = new bool[32];
	for(int i = 0; i < 32; i++)
		Ptemp[i] = LMes[i];
	for(i = 0; i < 32; i++)
		LMes[i] = RMes[i];
	for(i = 0; i < 32; i++)
		RMes[i] = Ptemp[i];
}
void IPR_Transmit(bool *Mes, bool *Cry)
{
	Transmit(Mes, Cry, IPR_Table, 64);
}
void Function(bool *Mes, bool *Cry, bool *K)
{
	bool *EBits = new bool[48];
	bool *SBits = new bool[32];
    E_function(Mes, EBits);
	for(int i = 0; i < 48; i++)
		EBits[i] = EBits[i] ^ K[i];
    S_function(EBits,SBits);
	P_Transmit(SBits, Cry);
}
///////////////////////////////////////////////////
//子密钥生成器所用函数
void PC1_Transmit(bool *Key, bool *CDkey)
{
	Transmit(Key, CDkey, PC1_Table, 56);
}
void PC2_Transmit(bool *CDkey, bool *SubKey)
{
	Transmit(CDkey, SubKey, PC2_Table, 48);
}
void LOOP_LS(bool *CDkey, int Turn)
{
	for(int t = 0; t < LOOP_Table[Turn]; t++)
	{
		bool bit = CDkey[0];
		for(int i =0; i < 27; i++)
			CDkey[i] = CDkey[i+1];
		CDkey[27] = bit;
	}
}
void CreateSubKey(bool *Key, bool **SubKey)
{
	bool *CDKey = new bool[56];
	bool *CKey = new bool[28];
	bool *DKey = new bool[28];
	PC1_Transmit(Key, CDKey);
	for(int i = 0; i < 28; i++)
	{
		CKey[i] = CDKey[i];
		DKey[i] = CDKey[i+28];
	}
	for(int turn = 0; turn < 16; turn++)
	{
		LOOP_LS(CKey, turn);
		LOOP_LS(DKey, turn);
		for(int i = 0; i < 56; i++)
			if(i < 28)
				CDKey[i] = CKey[i];
			else
				CDKey[i] = DKey[i-28];
		PC2_Transmit(CDKey, SubKey[turn]);
	}
}
/////////////////////////////////////////////////////
//加密函数
void DES_Encryption(bool *Mes, bool *Key, bool *Cry)
{
	bool *LRCry = new bool[64];
	bool *LCry = new bool[32];
	bool *RCry = new bool[32];
	bool *FCry = new bool[32];
	bool **SubKey = new bool*[16];
	for(int p = 0; p < 16; p++)
		SubKey[p] = new bool[48];
	CreateSubKey(Key, SubKey);
    IP_Transmit(Mes, LRCry);
    for(int i = 0; i < 32; i++)
	{
		LCry[i] = LRCry[i];
		RCry[i] = LRCry[i+32];
	}
	for(int turn = 0; turn < 16; turn++)
	{
		Function(RCry, FCry, SubKey[turn]);
		for(i = 0; i < 32; i++)
			LCry[i] = LCry[i] ^ FCry[i];
        Swap(LCry, RCry);
	}
	for(i = 0; i < 64; i++)
		if(i < 32)
			LRCry[i] = RCry[i];
		else
			LRCry[i] = LCry[i-32];
	IPR_Transmit(LRCry, Cry);
}
//解密函数
void DES_Decryption(bool *Cry, bool *Key, bool *Mes)
{
	bool *LRMes = new bool[64];
	bool *LMes = new bool[32];
	bool *RMes = new bool[32];
	bool *FMes = new bool[32];
	bool **SubKey = new bool*[16];
	for(int p = 0; p < 16; p++)
		SubKey[p] = new bool[48];
	CreateSubKey(Key, SubKey);
    IP_Transmit(Cry, LRMes);
    for(int i = 0; i < 32; i++)
	{
		LMes[i] = LRMes[i];
		RMes[i] = LRMes[i+32];
	}
	for(int turn = 0; turn < 16; turn++)
	{
		Function(RMes, FMes, SubKey[15-turn]);
		for(i = 0; i < 32; i++)
			LMes[i] = LMes[i] ^ FMes[i];
        Swap(LMes, RMes);
	}
	for(i = 0; i < 64; i++)
		if(i < 32)
			LRMes[i] = RMes[i];
		else
			LRMes[i] = LMes[i-32];
	IPR_Transmit(LRMes, Mes);
}
/////////////////////////////////////////////////////

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