[置顶] c语言实现记事本文件的 DES加密 解密

#include "stdio.h"

#include "memory.h"

#include "time.h"

#include "stdlib.h"

#define PLAIN_FILE_OPEN_ERROR -1

#define KEY_FILE_OPEN_ERROR -2

#define CIPHER_FILE_OPEN_ERROR -3

#define OK 1    

typedef char ElemType;

//初始置换表IP

int IP_Table[64] = {  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,

                                 56,48,40,32,24,16,8,0,

                                 58,50,42,34,26,18,10,2,

                                 60,52,44,36,28,20,12,4,

                                 62,54,46,38,30,22,14,6}; 

//逆初始置换表IP^-1

int IP_1_Table[64] = {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,

   32,0,40,8,48,16,56,24};

//扩充置换表E

int E_Table[48] = {31, 0, 1, 2, 3, 4,

              3,  4, 5, 6, 7, 8,

              7,  8,9,10,11,12,

              11,12,13,14,15,16,

              15,16,17,18,19,20,

              19,20,21,22,23,24,

              23,24,25,26,27,28,

              27,28,29,30,31, 0};

//置换函数P

int P_Table[32] = {15,6,19,20,28,11,27,16,

  0,14,22,25,4,17,30,9,

  1,7,23,13,31,26,2,8,

  18,12,29,5,21,10,3,24};

//S盒

int S[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}}};

//置换选择1

int PC_1[56] = {56,48,40,32,24,16,8,

          0,57,49,41,33,25,17,

          9,1,58,50,42,34,26,

          18,10,2,59,51,43,35,

          62,54,46,38,30,22,14,

          6,61,53,45,37,29,21,

          13,5,60,52,44,36,28,

          20,12,4,27,19,11,3};

//置换选择2

int PC_2[48] = {13,16,10,23,0,4,2,27,

          14,5,20,9,22,18,11,3,

          25,7,15,6,26,19,12,1,

          40,51,30,36,46,54,29,39,

          50,44,32,46,43,48,38,55,

          33,52,45,41,49,35,28,31};

//对左移次数的规定

int MOVE_TIMES[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};

int ByteToBit(ElemType ch,ElemType bit[8]);

int BitToByte(ElemType bit[8],ElemType *ch);

int Char8ToBit64(ElemType ch[8],ElemType bit[64]);

int Bit64ToChar8(ElemType bit[64],ElemType ch[8]);

int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]);

int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]);

int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]);

int DES_ROL(ElemType data[56], int time);

int DES_IP_Transform(ElemType data[64]);

int DES_IP_1_Transform(ElemType data[64]);

int DES_E_Transform(ElemType data[48]);

int DES_P_Transform(ElemType data[32]);

int DES_SBOX(ElemType data[48]);

int DES_XOR(ElemType R[48], ElemType L[48],int count);

int DES_Swap(ElemType left[32],ElemType right[32]);

int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]);

int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48], ElemType plainBlock[8]);

int DES_Encrypt(char *plainFile, char *keyStr,char *cipherFile);

int DES_Decrypt(char *cipherFile, char *keyStr,char *plainFile);

    

//字节转换成二进制

int ByteToBit(ElemType ch, ElemType bit[8]){

int cnt;

for(cnt = 0;cnt < 8; cnt++){

*(bit+cnt) = (ch>>cnt)&1;

}

return 0;

}

//二进制转换成字节

int BitToByte(ElemType bit[8],ElemType *ch){

int cnt;

for(cnt = 0;cnt < 8; cnt++){

*ch |= *(bit + cnt)<<cnt;

}

return 0;

}

//将长度为8的字符串转为二进制位串

int Char8ToBit64(ElemType ch[8],ElemType bit[64]){

int cnt;

for(cnt = 0; cnt < 8; cnt++){

ByteToBit(*(ch+cnt),bit+(cnt<<3));

}

return 0;

}

//将二进制位串转为长度为8的字符串

int Bit64ToChar8(ElemType bit[64],ElemType ch[8]){

int cnt;

memset(ch,0,8);

for(cnt = 0; cnt < 8; cnt++){

BitToByte(bit+(cnt<<3),ch+cnt);

}

return 0;

}

//生成子密钥

int DES_MakeSubKeys(ElemType key[64],ElemType subKeys[16][48]){

ElemType temp[56];

int cnt;

DES_PC1_Transform(key,temp);//PC1置换

for(cnt = 0; cnt < 16; cnt++){//16轮跌代，产生16个子密钥

DES_ROL(temp,MOVE_TIMES[cnt]);//循环左移

DES_PC2_Transform(temp,subKeys[cnt]);//PC2置换，产生子密钥

}

return 0;

}

//密钥置换1

int DES_PC1_Transform(ElemType key[64], ElemType tempbts[56]){

int cnt;

for(cnt = 0; cnt < 56; cnt++){

tempbts[cnt] = key[PC_1[cnt]];

}

return 0;

}

//密钥置换2

int DES_PC2_Transform(ElemType key[56], ElemType tempbts[48]){

int cnt;

for(cnt = 0; cnt < 48; cnt++){

tempbts[cnt] = key[PC_2[cnt]];

}

return 0;

}

//循环左移

int DES_ROL(ElemType data[56], int time){

ElemType temp[56];

//保存将要循环移动到右边的位

memcpy(temp,data,time);

memcpy(temp+time,data+28,time);

//前28位移动

memcpy(data,data+time,28-time);

memcpy(data+28-time,temp,time);

//后28位移动

memcpy(data+28,data+28+time,28-time);

memcpy(data+56-time,temp+time,time);

return 0;

}

//IP置换

int DES_IP_Transform(ElemType data[64]){

int cnt;

ElemType temp[64];

for(cnt = 0; cnt < 64; cnt++){

temp[cnt] = data[IP_Table[cnt]];

}

memcpy(data,temp,64);

return 0;

}

//IP逆置换

int DES_IP_1_Transform(ElemType data[64]){

int cnt;

ElemType temp[64];

for(cnt = 0; cnt < 64; cnt++){

temp[cnt] = data[IP_1_Table[cnt]];

}

memcpy(data,temp,64);

return 0;

}

//扩展置换

int DES_E_Transform(ElemType data[48]){

int cnt;

ElemType temp[48];

for(cnt = 0; cnt < 48; cnt++){

temp[cnt] = data[E_Table[cnt]];

}

memcpy(data,temp,48);

return 0;

}

//P置换

int DES_P_Transform(ElemType data[32]){

int cnt;

ElemType temp[32];

for(cnt = 0; cnt < 32; cnt++){

temp[cnt] = data[P_Table[cnt]];

}

memcpy(data,temp,32);

return 0;

}

//异或

int DES_XOR(ElemType R[48], ElemType L[48] ,int count){

int cnt;

for(cnt = 0; cnt < count; cnt++){

R[cnt] ^= L[cnt];

}

return 0;

}

//S盒置换

int DES_SBOX(ElemType data[48]){

int cnt;

int line,row,output;

int cur1,cur2;

for(cnt = 0; cnt < 8; cnt++){

cur1 = cnt*6;

cur2 = cnt<<2;

//计算在S盒中的行与列

line = (data[cur1]<<1) + data[cur1+5];

row = (data[cur1+1]<<3) + (data[cur1+2]<<2)

+ (data[cur1+3]<<1) + data[cur1+4];

output = S[cnt][line][row];

//化为2进制

data[cur2] = (output&0X08)>>3;

data[cur2+1] = (output&0X04)>>2;

data[cur2+2] = (output&0X02)>>1;

data[cur2+3] = output&0x01;

}

return 0;

}

//交换

int DES_Swap(ElemType left[32], ElemType right[32]){

ElemType temp[32];

memcpy(temp,left,32);

memcpy(left,right,32);

memcpy(right,temp,32);

return 0;

}

//加密单个分组

int DES_EncryptBlock(ElemType plainBlock[8], ElemType subKeys[16][48], ElemType cipherBlock[8]){

ElemType plainBits[64];

ElemType copyRight[48];

int cnt;

Char8ToBit64(plainBlock,plainBits);

//初始置换（IP置换）

DES_IP_Transform(plainBits);

//16轮迭代

for(cnt = 0; cnt < 16; cnt++){

memcpy(copyRight,plainBits+32,32);

//将右半部分进行扩展置换，从32位扩展到48位

DES_E_Transform(copyRight);

//将右半部分与子密钥进行异或操作

DES_XOR(copyRight,subKeys[cnt],48);

//异或结果进入S盒，输出32位结果

DES_SBOX(copyRight);

//P置换

DES_P_Transform(copyRight);

//将明文左半部分与右半部分进行异或

DES_XOR(plainBits,copyRight,32);

if(cnt != 15){

//最终完成左右部的交换

DES_Swap(plainBits,plainBits+32);

}

}

//逆初始置换（IP^1置换）

DES_IP_1_Transform(plainBits);

Bit64ToChar8(plainBits,cipherBlock);

return 0;

}

//解密单个分组

int DES_DecryptBlock(ElemType cipherBlock[8], ElemType subKeys[16][48],ElemType plainBlock[8]){

ElemType cipherBits[64];

ElemType copyRight[48];

int cnt;

Char8ToBit64(cipherBlock,cipherBits);

//初始置换（IP置换）

DES_IP_Transform(cipherBits);

//16轮迭代

for(cnt = 15; cnt >= 0; cnt--){

memcpy(copyRight,cipherBits+32,32);

//将右半部分进行扩展置换，从32位扩展到48位

DES_E_Transform(copyRight);

//将右半部分与子密钥进行异或操作

DES_XOR(copyRight,subKeys[cnt],48);

//异或结果进入S盒，输出32位结果

DES_SBOX(copyRight);

//P置换

DES_P_Transform(copyRight);

//将明文左半部分与右半部分进行异或

DES_XOR(cipherBits,copyRight,32);

if(cnt != 0){

//最终完成左右部的交换

DES_Swap(cipherBits,cipherBits+32);

}

}

//逆初始置换（IP^1置换）

DES_IP_1_Transform(cipherBits);

Bit64ToChar8(cipherBits,plainBlock);

return 0;

}

//加密文件

int DES_Encrypt(char *plainFile, char *keyStr,char *cipherFile){

FILE *plain,*cipher;

int count;

ElemType plainBlock[8],cipherBlock[8],keyBlock[8];

ElemType bKey[64];

ElemType subKeys[16][48];

if((plain = fopen(plainFile,"rb")) == NULL){

return PLAIN_FILE_OPEN_ERROR;

}

if((cipher = fopen(cipherFile,"wb")) == NULL){

return CIPHER_FILE_OPEN_ERROR;

}

//设置密钥

memcpy(keyBlock,keyStr,8);

//将密钥转换为二进制流

Char8ToBit64(keyBlock,bKey);

//生成子密钥

DES_MakeSubKeys(bKey,subKeys);

while(!feof(plain)){

//每次读8个字节，并返回成功读取的字节数

if((count = fread(plainBlock,sizeof(char),8,plain)) == 8){

DES_EncryptBlock(plainBlock,subKeys,cipherBlock);

fwrite(cipherBlock,sizeof(char),8,cipher);

}

}

if(count){

//填充

memset(plainBlock + count,'\0',7 - count);

//最后一个字符保存包括最后一个字符在内的所填充的字符数量

plainBlock[7] = 8 - count;

DES_EncryptBlock(plainBlock,subKeys,cipherBlock);

fwrite(cipherBlock,sizeof(char),8,cipher);

}

fclose(plain);

fclose(cipher);

return OK;

}

//解密文件

int DES_Decrypt(char *cipherFile, char *keyStr,char *plainFile){

FILE *plain, *cipher;

int count,times = 0;

long fileLen;

ElemType plainBlock[8],cipherBlock[8],keyBlock[8];

ElemType bKey[64];

ElemType subKeys[16][48];

if((cipher = fopen(cipherFile,"rb")) == NULL){

return CIPHER_FILE_OPEN_ERROR;

}

if((plain = fopen(plainFile,"wb")) == NULL){

return PLAIN_FILE_OPEN_ERROR;

}

//设置密钥

memcpy(keyBlock,keyStr,8);

//将密钥转换为二进制流

Char8ToBit64(keyBlock,bKey);

//生成子密钥

DES_MakeSubKeys(bKey,subKeys);

//取文件长度

fseek(cipher,0,SEEK_END);//将文件指针置尾

fileLen = ftell(cipher);//取文件指针当前位置

rewind(cipher);//将文件指针重指向文件头

while(1){

//密文的字节数一定是8的整数倍

fread(cipherBlock,sizeof(char),8,cipher);

DES_DecryptBlock(cipherBlock,subKeys,plainBlock);

times += 8;

if(times < fileLen){

fwrite(plainBlock,sizeof(char),8,plain);

}

else{

break;

}

}

//判断末尾是否被填充

if(plainBlock[7] < 8){

for(count = 8 - plainBlock[7]; count < 7; count++){

if(plainBlock[count] != '\0'){

break;

}

}

}

if(count == 7){//有填充

fwrite(plainBlock,sizeof(char),8 - plainBlock[7],plain);

}

else{//无填充

fwrite(plainBlock,sizeof(char),8,plain);

}

fclose(plain);

fclose(cipher);

return OK;

}

int main()

{

clock_t a,b;

a = clock();

DES_Encrypt("1.txt","key.txt","2.txt");

b = clock();

printf("加密消耗%d毫秒\n",b-a);

system("pause");

a = clock();

DES_Decrypt("2.txt","key.txt","3.txt");

b = clock();

printf("解密消耗%d毫秒\n",b-a);

getchar();

return 0;

}