#include <iostream>
#include <fstream>
//讀取緩沖區(qū)的指定位.
#define GET_BIT(p_array, bit_index)  \
			((p_array[(bit_index) >> 3] >> (7 - ((bit_index) & 0x07))) & 0x01)

//設(shè)置緩沖區(qū)的指定位.
#define SET_BIT(p_array, bit_index, bit_val) \
			if (1 == (bit_val)) \
			{\
				p_array[(bit_index) >> 3] |= 0x01 << (7 - ((bit_index) & 0x07));\
			}\
			else\
			{\
				p_array[(bit_index) >> 3] &= ~(0x01 << (7 - ((bit_index) & 0x07)));\
			}
using namespace std;


// 初始置換 
const unsigned char Table_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 
}; 

// 逆初始置換 
const unsigned char Table_InverseIP[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 
}; 

// 擴沖置換
const unsigned char Table_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 
}; 

// 密鑰初始置換 
const unsigned char Table_PC1[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 
}; 

// 左右移運算 
const signed char Table_Move[2][16] = 
{ 
	//加密左移
	{1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1},

	//解密右移
	{0, -1, -2, -2, -2, -2, -2, -2, -1, -2, -2, -2, -2, -2, -2, -1}
}; 

// 密鑰壓縮置換 
const unsigned char Table_PC2[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 
}; 

// S盒 
const unsigned char Table_SBOX[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盒置換 
const unsigned char Table_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 
}; 

//對兩塊大小相同的內(nèi)存區(qū)進行異或
//異或結(jié)果保存到第一塊內(nèi)存
//unsigned char * p_buf_1		內(nèi)存區(qū)1
//const unsigned char * p_buf_2	內(nèi)存區(qū)2
//unsigned char bytes			內(nèi)存區(qū)大小(單位：字節(jié))
void Xor(unsigned char * p_buf_1, const unsigned char * p_buf_2, unsigned char bytes)
{
	while(bytes > 0)
	{
		bytes--;

		p_buf_1[bytes] ^= p_buf_2[bytes];
	}
}

//將緩沖區(qū)從第bit_start位到第bit_end進行循環(huán)左移
//offset只能是1，2
//本段代碼還可以優(yōu)化。
void move_left(unsigned char * p_input, unsigned char bit_start, unsigned char bit_end, unsigned char offset) 
{ 
	unsigned char b_val = 0;
	unsigned char b_tmp1 = 0;
	unsigned char b_tmp2 = 0;

	//讀取bit_start位
	b_tmp1 = GET_BIT(p_input, bit_start);
	b_tmp2 = GET_BIT(p_input, bit_start + 1);

	//循環(huán)左移offset位
	for(; bit_start <= (bit_end - offset); bit_start++)
	{
		b_val = GET_BIT(p_input, bit_start + offset);
		SET_BIT(p_input, bit_start, b_val);
	}

	//將bit_start開始的offset位移到bit_end后頭來
	if (1 == offset)
	{
		SET_BIT(p_input, bit_end, b_tmp1);
	}
	else
	{
		SET_BIT(p_input, bit_end, b_tmp2);
		SET_BIT(p_input, bit_end - 1, b_tmp1);
	}
} 

//將緩沖區(qū)從第bit_start位到第bit_end進行循環(huán)右移
//offset只能是1，2
//本段代碼在性能上還可以優(yōu)化。
void move_right(unsigned char * p_input, unsigned char bit_start, unsigned char bit_end, unsigned char offset) 
{ 
	unsigned char b_val = 0;
	unsigned char b_tmp1 = 0;
	unsigned char b_tmp2 = 0;

	//讀取bit_end位
	b_tmp1 = GET_BIT(p_input, bit_end);
	b_tmp2 = GET_BIT(p_input, bit_end - 1);

	//循環(huán)左移offset位
	for(; bit_end >= (bit_start + offset); bit_end--)
	{
		b_val = GET_BIT(p_input, bit_end - offset);
		SET_BIT(p_input, bit_end, b_val);
	}

	//將bit_end倒數(shù)的offset位移到bit_start來
	if (1 == offset)
	{
		SET_BIT(p_input, bit_start, b_tmp1);
	}
	else
	{
		SET_BIT(p_input, bit_start, b_tmp2);
		SET_BIT(p_input, bit_start + 1, b_tmp1);
	}
} 

//緩沖區(qū)移位
//offset大于0時左移
//offset小于0時右移
void move_bits(unsigned char * p_input, unsigned char bit_start, unsigned char bit_end, char offset)
{
	if(0 < offset)	//左移
	{
		move_left(p_input, bit_start, bit_end, offset);	
	}	
	else if(0 > offset)	//右移
	{
		move_right(p_input, bit_start, bit_end, -offset);
	}
}

//通用置換函數(shù), bits <= 64
//p_input與p_output不能指向同一個地址，否則置換會出錯。
void Permutation(const unsigned char * p_input, unsigned char * p_output, const unsigned char * Table, unsigned char bits) 
{ 
	unsigned char b_val = 0;
	unsigned char bit_index = 0;

	for(bit_index = 0; bit_index < bits; bit_index++) 
	{
		b_val = GET_BIT(p_input, Table[bit_index] - 1);
		
		SET_BIT(p_output, bit_index, b_val);
	}
} 

//獲取從bit_s為起始的第1, 6 位組成行
unsigned char S_GetLine(unsigned char * p_data_ext, unsigned char bit_s)
{
	return (GET_BIT(p_data_ext, bit_s + 0) << 1) + GET_BIT(p_data_ext, bit_s + 5);
}

//獲取從bit_s為起始的第2,3,4,5位組成列
unsigned char S_GetRow(unsigned char * p_data_ext, unsigned char bit_s)
{
	unsigned char row;

	//2,3,4,5位組成列
	row = GET_BIT(p_data_ext, bit_s + 1);
	row <<= 1; 
	row += GET_BIT(p_data_ext, bit_s + 2);
	row <<= 1; 
	row += GET_BIT(p_data_ext, bit_s + 3);
	row <<= 1; 
	row += GET_BIT(p_data_ext, bit_s + 4);

	return row;
}


void des(const unsigned char * p_data, const unsigned char * p_key,  unsigned char * p_output, unsigned char mode)
{
	unsigned char loop = 0;		//16輪運算的循環(huán)計數(shù)器
	unsigned char key_tmp[8];	//密鑰運算時存儲中間結(jié)果
	unsigned char sub_key[6];	//用于存儲子密鑰

	unsigned char * p_left;
	unsigned char * p_right;

	unsigned char p_right_ext[8];	//R[i]經(jīng)過擴展置換生成的48位數(shù)據(jù)(6字節(jié)), 及最終結(jié)果的存儲
	unsigned char p_right_s[4];		//經(jīng)過S_BOX置換后的32位數(shù)據(jù)(4字節(jié))

	unsigned char s_loop = 0;		//S_BOX置換的循環(huán)計數(shù)器

	Permutation(p_key, key_tmp, Table_PC1, 56);
	Permutation(p_data, p_output, Table_IP, 64);

	p_left  = p_output;		//L0
	p_right = &p_output[4];	//R0

	for(loop = 0; loop < 16; loop++)
	{
		move_bits(key_tmp, 0, 27, Table_Move[mode][loop]);
		move_bits(key_tmp, 28, 55, Table_Move[mode][loop]);
		Permutation(key_tmp, sub_key, Table_PC2, 48);
		Permutation(p_right, p_right_ext, Table_E, 48);
		Xor(p_right_ext, sub_key, 6);

		//S_BOX置換
		for(s_loop = 0; s_loop < 4; s_loop++)
		{
			unsigned char s_line = 0;
			unsigned char s_row = 0;
			unsigned char s_bit = s_loop * 12;

			s_line = S_GetLine(p_right_ext, s_bit);
			s_row  = S_GetRow(p_right_ext,	s_bit);
			
			p_right_s[s_loop] = Table_SBOX[s_loop * 2][s_line][s_row];

			s_bit += 6;
			
			s_line = S_GetLine(p_right_ext, s_bit);
			s_row  = S_GetRow(p_right_ext,	s_bit);
			
			p_right_s[s_loop] <<= 4;
			p_right_s[s_loop] += Table_SBOX[(s_loop * 2) + 1][s_line][s_row];
		}

		//P置換
		Permutation(p_right_s, p_right_ext, Table_P, 32);

		Xor(p_right_ext, p_left, 4);

		memcpy(p_left, p_right, 4);
		memcpy(p_right, p_right_ext, 4);
	}

	memcpy(&p_right_ext[4], p_left, 4);
	memcpy(p_right_ext,	p_right, 4);

	Permutation(p_right_ext, p_output, Table_InverseIP, 64);		
}

void Encode(ifstream &in,ofstream &out){
	char c;
	int i=0;
	unsigned char key[9] = "12345678";
	unsigned char en_data[8];
	unsigned char en_out_put[8];
	for(int k=0;k<8;k++){
		en_out_put[k]='\0';
	}

	while(in.get(c)){
		if(i<8){
			en_data[i]=c;
			i++;
		}
		else{
			Xor(en_data,en_out_put,8);
			des(en_data, key, en_out_put,0);
			for(int j=0;j<8;j++){
				out << en_out_put[j];
			}
			en_data[0]=c;
			i=1;
		}
	}
	
	if(i==8){
		Xor(en_data,en_out_put,8);
		des(en_data, key, en_out_put,0);
		for(int j=0;j<8;j++){
			out << en_out_put[j];
		}
	}
	else{		
		Xor(en_data,key,8);
		for(int j=0;j<i;j++){
			out << en_data[j];
		}
	}
}

void Decode(ifstream &in,ofstream &out){
	char c;
	int i=0;
	unsigned char key[9] = "12345678";
	unsigned char en_data[8];
	unsigned char en_out_put[8];
	unsigned char en_out_pre[8];
	for(int k=0;k<8;k++){
		en_out_pre[k]='\0';
	}

	while(in.get(c)){
		if(i<8){
			en_data[i]=c;
			i++;
		}
		else{
			des(en_data, key, en_out_put,1);
			Xor(en_out_put,en_out_pre,8);
			memcpy(en_out_pre,en_data,8);
			for(int j=0;j<8;j++){
				out << en_out_put[j];
			}
			en_data[0]=c;
			i=1;
		}
	}
	
	if(i==8){
		des(en_data, key, en_out_put,1);
		Xor(en_out_put,en_out_pre,8);
		for(int j=0;j<8;j++){
			out << en_out_put[j];
		}
	}
	else{		
		Xor(en_data,key,8);
		for(int j=0;j<i;j++){
			out << en_data[j];
		}
	}
}


void print(){
	cout << "*******************DES加密軟件*************************" << endl;
	cout << "1.加密" << endl;
	cout << "2.解密" << endl;
	cout << "*******************************************************" << endl;
	cout << "輸入你的選擇（1或2）:";
}

int main()
{
	char inpath[80];
	char outpath[80];
	int choice;
	ifstream inFile;
	ofstream outFile;

	print();

	cin >> choice;
	cin.get();
	switch(choice){
		case 1:
			cout << "輸入加密文件路徑(包括文件名）：" << endl;
			cin.getline(inpath,80,'\n');
			inFile.open(inpath,ios::binary|ios::in);
			if(!inFile){
				cerr << "inFile could not be opened!" << endl;
				exit(1);
			}
			cout << "輸入加密后文件保存的路徑（包括文件名):" << endl;
			cin.getline(outpath,80,'\n');
			outFile.open(outpath,ios::binary|ios::out);
			if(!outFile){
				cerr << "outFile could not be opened!" << endl;
				exit(1);
			}
			cout << "加密中。。。。。請稍后。。。。。" << endl;
			Encode(inFile,outFile);
			cout << "加密完成！" << endl;
			inFile.close();
			outFile.close();
			break;
		case 2:
			cout << "輸入解密文件路徑(包括文件名）：" << endl;
			cin.getline(inpath,80,'\n');
			inFile.open(inpath,ios::binary|ios::in);
			if(!inFile){
				cerr << "inFile could not be opened!" << endl;
				exit(1);
			}
			cout << "輸入解密后文件保存的路徑（包括文件名):" << endl;
			cin.getline(outpath,80,'\n');
			outFile.open(outpath,ios::binary|ios::out);
			if(!outFile){
				cerr << "outFile could not be opened!" << endl;
				exit(1);
			}
			cout << "解密中。。。。。請稍后。。。。。" << endl;
			Decode(inFile,outFile);
			cout << "解密完成！" << endl;
			inFile.close();
			outFile.close();
			break;
	}
	
	cout << "謝謝使用~ ~" << endl;

	return 0;
}