DES-加解密C语言实现

/*
create by fanchenyang at 2021 
*/ 

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
/*
	初始置换与终止置换
 	置换的type决定使用的置换方式 
 	type -> 0 初始置换
	type -> 1 终止置换
	
	将原始64位数据进行排列  
*/
void pBoxChange(int * node,int type,int *resu){ 
	int boxInit[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};
	int  boxEnd [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};
	int var;
	int * box;
	if(type == 0){
		box = boxInit;
	}else if(type == 1){
		box = boxEnd;
	}else{
		printf("传入类型有误，请重
");
		return;
	}
	for(int i = 0; i < 64; i++){
		*(resu + i) = node[*(box + i) - 1];
	}
}

// p盒置换 
void pBoxCh(int * node,int * res){
	int box[] = {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
				};
	for(int i = 0; i < 32; i++){
		*(res + i) = node[*(box + i) - 1];
	}
} 
// 位选择函数 
// pri 32
// tar 48
// 将32位明文扩展为48位 
void fun_e(int * pri,int * tar){
	int box_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
					};
	for(int i = 0 ; i < 48 ; i++){
		*(tar + i) = *(pri + *(box_e + i) - 1);
	}
	
}
/*
S盒压缩
将48位压缩为32位 
*/ 
void SBoxChange(int  *right,int * res){
	int box [8][64]  = {	
						{
						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
						}
			};
			int vv = 0;
		for(int i = 0 ; i < 8; i++){
			// 拿到行列值
			int hang  = *(right + i * 6 + 0) * 2 + *(right + i * 6 + 5); 
			int lie = 0;
			for(int j = 4 ; j > 0 ; j--){
				lie += *(right + i * 6 + j) * pow(2,4-j); 
			}
			int var[4] = {0,0,0,0};
//			printf("行 %d列%d 值
",hang,lie); 
			int value = *(*(box + i) + (hang* 16) + lie);
//			printf("value=%d",value);
			// 将value分解为二进制
			for(int j = 0 ; j < 4 ; j++){
				var[3 - j] = value % 2;
				value /= 2;
			}
			for(int j = 0 ; j < 4 ; j++)
				*(res + vv++) = var[j]; 
		}				 
}

void getMiYao(int key[64],int keyi[][48]){
	int pc_1 [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
					};
	int pc_2[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
					};
	int pp [56] ;
	for(int i = 0 ; i < 56 ; i++){
		*(pp + i) = key[*(pc_1 + i) - 1];
	}
	for(int i = 0 ; i < 16 ; i++){
		if(i == 0 ||i == 1|| i == 8||i == 15){
			// 循环左移一位 
			int var = *(pp);
			for(int j = 1 ; j < 28 ; j++){
				*(pp + j - 1) =*(pp + j);
			} 
			*(pp + 27) = var;
			var = *(pp + 28);
			for(int j = 29 ; j < 56 ; j++){
				*(pp + j -1) = *(pp + j);
			}
			*(pp + 55) = var;
		}else{
			//循环左移两位 
			int var1 = *(pp);
			int var2 = *(pp+1);
			for(int j = 2 ; j < 28 ; j++){
				*(pp + j - 1) =*(pp + j);
			} 
			*(pp + 26) = var1;
			*(pp + 27) = var2;
			var1 = *(pp + 28);
			var2 = *(pp + 29);
			for(int j = 30 ; j < 56 ; j++){
				*(pp + j -1) = *(pp + j);
			}
			*(pp + 54) = var1;
			*(pp + 55) = var2;
		}
		for(int j = 0 ; j < 48 ; j++){
			*(keyi[i]+j) = *(pp + (*(pc_2 + j) - 1));
		}
	}
	
}
// primary 明文 加密后的结果仍放其中 
void DESEncode(int * primary,int miyao[][48]){
	// 将明文经过p盒置换的结果放在result中 
	int result [64] = {};
	pBoxChange(primary,0,result);
	

	for(int i = 0 ; i < 16 ; i++){
		int asd[48];
		
		// 对r0做备份 
		int ee[32];
		for(int j = 0 ; j < 32 ;j++){
			ee[j] = *(result + j + 32);
		}
		
		// 存放48位扩展明文 
		int e[48];
		//扩展明文  
		fun_e(result + 32,e);
		
//		printf("扩展明文完成
");
		// 存放32位Sbox转换后的数据 
		int ss[32]; 
		
		for(int j = 0 ; j < 48 ; j++){
			*(asd + j) = *(e + j) ^ *(*(miyao + i) + j);
//			printf("%d",*(asd + j));
		}
		
//		printf("sbox开始
");
		SBoxChange(asd,ss); 
//		printf("sbox完成
");
		
		int p_result[32];
		pBoxCh(ss,p_result);
//		printf("
");
//		for(int i = 0 ; i < 32 ; i++){
//			if(i % 6 == 0)
//				printf("
");
//				
//			printf("%d ",ss[i]);
//		}
//		printf("===
");
//			
//		
		for(int j = 0  ; j < 32 ; j++){
			result[32 + j] = result[j] ^ p_result[j];// r1 = l0 ^ p_result
			result[j] = ee[j];							// l1 = r0
		}
		
//		for(int i = 0 ; i < 64 ; i++){
//			
//			if(i % 8 == 0)
//				printf("
");
//				
//			printf("%d ",result[i]);
//			
//		}
				
//		printf("
");	
	}
	//逆置换
	pBoxChange(result,1,primary);	
} 
// DES解密 
void Decode(int * primary,int miyao[][48]){
// 将明文经过p盒置换的结果放在result中 
	int result [64] = {};
	pBoxChange(primary,0,result);
	

	for(int i = 0 ; i < 16 ; i++){
		int asd[48];
		
		// 对l0做备份 
		int ee[32];
		for(int j = 0 ; j < 32 ;j++){
			ee[j] = *(result + j);
		}
		
		// 存放48位扩展明文 
		int e[48];
		//扩展明文  
		fun_e(result,e);
		
//		printf("扩展明文完成 %d
",i);
		// 存放32位Sbox转换后的数据 
		int ss[32]; 
		
		for(int j = 0 ; j < 48 ; j++){
			*(asd + j) = *(e + j) ^ *(*(miyao + 15 - i) + j);
		}
		
//		printf("sbox开始
");
		SBoxChange(asd,ss); 
//		printf("sbox完成
");
		
		int p_result[32];
		pBoxCh(ss,p_result);
//		printf("
");
//		for(int i = 0 ; i < 32 ; i++){
//			if(i % 6 == 0)
//				printf("
");
//				
//			printf("%d ",ss[i]);
//		}
//		printf("===
");
			
		
		for(int j = 0  ; j < 32 ; j++){
			result[j] = result[j + 32] ^ p_result[j];// r1 = l0 ^ p_result
			result[j + 32] = ee[j];							// l1 = r0
		}
		
	}
	//逆置换
	pBoxChange(result,1,primary);
}
// 测试 
//void test(){
//	int key[64] = {0}; 
//	int x[64] = {0};
//	printf("

");
//	DESEncode(x,key);
//		for(int i = 0 ; i < 64 ; i++){
//			if(i % 8 == 0){
//				printf("
");
//			}
//			printf("%d",*(x+i));
//		}
//	Decode(x,key);
//	for(int i = 0 ; i < 64 ; i++){
//			if(i % 8 == 0){
//				printf("
");
//			}
//			printf("%d",*(x+i));
//	}
//}
// 将字符串转化为二进制数组 
void changeStringToarray(char * s,int * array){
//	for(int i = 0 ; i < size i ++){
		// 每8个字符封装为一个64位二进制字符串，剩余的补零 
//	}

	for(int i = 0 ; i < 8 ; i++){
		for(int j = 0 ; j < 8 ;j ++){
			*(array + 8 * i + j) = (*(s+i) >> (7 - j)) & 1;
		}
	}
	
}
void changeArrayToString(int * array,char * s){
	for(int i = 0 ; i < 8 ; i++)
		*(s + i) = 0;
	for(int i = 0 ; i < 64 ; i++){
		*(s + i / 8) += *(array + i) * pow(2,7 - i % 8);	
	}
//	printf("
");
//	for(int i = 0 ; i < 8 ; i++)
//		printf("%c
",*(s+i));
}
// 输入 密文 输入 秘钥 
void input(){
	printf("加密请输入E解密输入D
");
	char pp;
	int type;
	scanf("%c",&pp);
	char s[100] = {''};
	char d[100] = {''};
	if(pp == 'D' || pp == 'd'){
		type = 1;
		printf("请输入要解密的文件路径
");
		scanf("%s",s);
		printf("加密后文件存放路径
");
		scanf("%s",d);
	}	
	else if(pp == 'E' || pp == 'e'){
		type = 0;
		printf("请输入要加密的文件路径
");
		scanf("%s",s);
		printf("加密后文件存放路径
");
		scanf("%s",d);
	}
	else {
		printf("输入异常
");
		return ;
	}		
 char key[8];
 printf("请先输入 8 位 字符 秘钥 
");
 for(int i = 0 ; i < 8 ; i++){
  scanf("%c",key + i);
 }
 int keybit [64];
 changeStringToarray(key,keybit);
 //	//初始化16轮迭代密钥 
	int miyao [16][48] = {{0}};
	getMiYao(keybit,miyao);
 char miwen[9] = {''};
 //读取明文文件 每8位 分为一组
 FILE * fs;
	
// fs = fopen("D:\DES\明文.txt","r");
	fs = fopen(s,"r");
 FILE * fo = fopen(d,"w");
 // 读取8位
 char c;
 int curIndex = 0;
 char container [8]; 
 if(fs == NULL)
 	printf("asda
");
 while((c = fgetc(fs)) != EOF){
//  printf("%d
",curIndex);
  container[curIndex] = c;
  if(curIndex == 7){
   // size等于8说明集齐一组 数据
   // 调用函数 得到加密 密文
   //  TODO 将密文 写在 输出流中
   	int a[64];
  	changeStringToarray(container,a);
  	if(type == 0)
  		DESEncode(a,miyao);
  		
  	else
  		Decode(a,miyao);
	changeArrayToString(a,miwen);
   	fputs(miwen,fo);
//   	printf("asdasd
");
  }
  	curIndex = (++curIndex) % 8;
 }
 // 如果剩余数据凑不够8个字符即64位二进制，默认按照高位补 “空格 ”
 // 如果 curIndex == 0 说明 每组8位刚刚好 直接return
 if(curIndex != 0){
  // 补位并计算
  for(int  i = curIndex; i < 8 ; i++){
   container[i] = ' ';
  }
  //TODO 调用函数 转为 密文 并写到输出流
 	int a[64];
  	changeStringToarray(container,a);
  		if(type == 0)
  		DESEncode(a,miyao);
  	else
  		Decode(a,miyao);
  	changeArrayToString(a,miwen);
  	fputs(miwen,fo);
 }
 fclose(fo);
 fclose(fs); 
}
int main(){
	input(); 
	return 0;
}