#include "Encryption.h"

//从机加密表
const unsigned char EPT_Table[32][6] = {
	{1, 6, 4, 2, 3, 5}, {2, 4, 6, 3, 5, 1}, {3, 5, 6, 2, 1, 4}, {5, 3, 2, 1, 4, 6},
	{4, 2, 3, 1, 5, 6}, {6, 3, 5, 1, 4, 2}, {3, 5, 2, 6, 4, 1}, {2, 5, 4, 3, 1, 6},
	{2, 4, 1, 5, 3, 6}, {4, 6, 1, 3, 2, 5}, {4, 2, 1, 5, 6, 3}, {3, 2, 6, 5, 1, 4},
	{2, 6, 5, 1, 4, 3}, {6, 4, 3, 1, 2, 5}, {1, 6, 3, 2, 4, 5}, {5, 3, 4, 6, 2, 1},
	{5, 3, 1, 2, 6, 4}, {1, 4, 2, 6, 5, 3}, {3, 5, 2, 1, 4, 6}, {6, 1, 4, 2, 3, 5},
	{4, 1, 2, 5, 3, 6}, {4, 2, 6, 3, 5, 1}, {2, 6, 1, 4, 3, 5}, {4, 3, 1, 5, 6, 2},
	{5, 1, 2, 4, 6, 3}, {6, 5, 1, 3, 4, 2}, {2, 1, 6, 3, 5, 4}, {1, 5, 6, 3, 4, 2},
	{3, 6, 5, 4, 2, 1}, {1, 2, 6, 3, 5, 4}, {4, 6, 5, 3, 2, 1}, {5, 3, 4, 2, 6, 1}
};

//从机解密表：
const unsigned char DPT_Table[32][5] ={
	{1, 4, 2, 3, 5}, {2, 4, 3, 5, 1}, {3, 5, 2, 1, 4}, {5, 3, 2, 1, 4},
	{4, 2, 3, 1, 5}, {3, 5, 1, 4, 2}, {3, 5, 2, 4, 1}, {2, 5, 4, 3, 1},
	{2, 4, 1, 5, 3}, {4, 1, 3, 2, 5}, {4, 2, 1, 5, 3}, {3, 2, 5, 1, 4},
	{2, 5, 1, 4, 3}, {4, 3, 1, 2, 5}, {1, 3, 2, 4, 5}, {5, 3, 4, 2, 1},
	{5, 3, 1, 2, 4}, {1, 4, 2, 5, 3}, {3, 2, 1, 4, 5}, {1, 4, 5, 2, 3},
	{4, 1, 2, 5, 3}, {4, 2, 3, 5, 1}, {2, 1, 4, 3, 5}, {4, 3, 1, 5, 2},
	{5, 1, 2, 4, 3}, {5, 1, 3, 4, 2}, {2, 1, 3, 5, 4}, {1, 5, 3, 4, 2},
	{3, 5, 4, 2, 1}, {1, 2, 3, 5, 4}, {4, 5, 3, 2, 1}, {5, 3, 4, 2, 1}
};

//数据位加密表：
const unsigned char EPT_D[32] = {
	0x23, 0x4c, 0x92, 0x38, 0x52, 0xa4, 0x9a, 0x61, 
	0x86, 0xc8, 0x70, 0x16, 0x32, 0x58, 0x62, 0x83, 
	0xa5, 0x16, 0x1c, 0x49, 0x48, 0xc1, 0x8c, 0x91, 
	0xd0, 0x2c, 0x49, 0x42, 0xc1, 0x8c, 0x98, 0xd0
};

/****************************************************************/
/*			加密函数										*/
/*																	*/
/*函数入口:	*data,未加密的普通协议数据					*/
/*																*/
/*函数出口:	*EPT_data，生成的加密协议				*/
/****************************************************************/
void Encrypt_Code(unsigned char *data, unsigned char *EPT_data) {
	unsigned char Edata[6];
	unsigned char i = 0;
	unsigned char check;
	unsigned char ept_byte;

	check = (data[0]+data[1]+data[2]+data[3]+data[4]+data[5]) % 0xff;
	ept_byte = check % 32;

	for (i = 0; i < 6; i++) {
		Edata[i] = ((~(data[i] & EPT_D[ept_byte])) & EPT_D[ept_byte]) | (data[i] & (~EPT_D[ept_byte]));
	}

	for (i = 0; i < 6; i++) {
		EPT_data[i] = Edata[EPT_Table[ept_byte][i]-1];
	}

	EPT_data[6] = ((~(check & 0xaa)) & 0xaa) | (check & 0x55);
}

/****************************************************************/
/*						解密函数							*/
/*																*/
/*函数入口：	*EPT_data，需要解密的加密协议	*/
/*																*/	
/*函数出口：	*DPT_data，生成的普通协议			*/
/****************************************************************/
void Decrypt_Code(unsigned char *EPT_data,unsigned char *DPT_data) {
	unsigned char data[5];
	unsigned char i = 0;
	unsigned char check;
	unsigned char ept_byte;

	check = ((~(EPT_data[5]&0xaa))&0xaa)|(EPT_data[5]&0x55);
	ept_byte = check % 32;

	for(i=0;i<5;i++) {
		data[i] = ((~(EPT_data[i]&EPT_D[ept_byte]))&EPT_D[ept_byte])|(EPT_data[i]&(~EPT_D[ept_byte]));
	}
	for(i=0;i<5;i++) {
		DPT_data[DPT_Table[ept_byte][i]-1] = data[i];
	}
	DPT_data[5] = check;
}