文件加密的简单实现(C语言)
需求:以DWORD为单位对文件进行加密,将每个DWORD与0xfcba0000做异或,写入另一个文件
解答:
心得:
char*转DWORD:dwData = *(DWORD*)pbBuffer;
DWORD转char*:pbBuffer = (char *) &dwData;
解答:
#include <stdio.h>
#include <stdlib.h>
#define DWORD unsigned long
#define BYTE unsigned char
#define false 0
#define true 1
int main(int argc, char *argv[])
{
FILE *hSource;
FILE *hDestination;
DWORD dwKey=0xfcba0000;
char* pbBuffer;
DWORD dwBufferLen=sizeof(DWORD);
DWORD dwCount;
DWORD dwData;
if(argv[1]==0||argv[2]==0)
{
printf("missing argument!\n");
return false;
}
char* szSource=argv[1];
char* szDestination=argv[2];
hSource = fopen(szSource,"rb");// 打开源文件.
hDestination = fopen(szDestination,"wb"); //打开目标文件
if (hSource==NULL) {printf("open Source File error !"); return false ;}
if (hDestination==NULL){ printf("open Destination File error !"); return false ;}
//分配缓冲区
pbBuffer=(char* )malloc(dwBufferLen);
do {
// 从源文件中读出dwBlockLen个字节
dwCount = fread(pbBuffer, 1, dwBufferLen, hSource);
//加密数据
dwData = *(DWORD*)pbBuffer; //char* TO dword
dwData^=dwKey; //xor operation
pbBuffer = (char *) &dwData;
// 将加密过的数据写入目标文件
fwrite(pbBuffer, 1, dwCount, hDestination);
} while(!feof(hSource));
//关闭文件、释放内存
fclose(hSource);
fclose(hDestination);
printf("%s is encrypted to %s\n",szSource,szDestination);
return 0;
}
#include <stdlib.h>
#define DWORD unsigned long
#define BYTE unsigned char
#define false 0
#define true 1
int main(int argc, char *argv[])
{
FILE *hSource;
FILE *hDestination;
DWORD dwKey=0xfcba0000;
char* pbBuffer;
DWORD dwBufferLen=sizeof(DWORD);
DWORD dwCount;
DWORD dwData;
if(argv[1]==0||argv[2]==0)
{
printf("missing argument!\n");
return false;
}
char* szSource=argv[1];
char* szDestination=argv[2];
hSource = fopen(szSource,"rb");// 打开源文件.
hDestination = fopen(szDestination,"wb"); //打开目标文件
if (hSource==NULL) {printf("open Source File error !"); return false ;}
if (hDestination==NULL){ printf("open Destination File error !"); return false ;}
//分配缓冲区
pbBuffer=(char* )malloc(dwBufferLen);
do {
// 从源文件中读出dwBlockLen个字节
dwCount = fread(pbBuffer, 1, dwBufferLen, hSource);
//加密数据
dwData = *(DWORD*)pbBuffer; //char* TO dword
dwData^=dwKey; //xor operation
pbBuffer = (char *) &dwData;
// 将加密过的数据写入目标文件
fwrite(pbBuffer, 1, dwCount, hDestination);
} while(!feof(hSource));
//关闭文件、释放内存
fclose(hSource);
fclose(hDestination);
printf("%s is encrypted to %s\n",szSource,szDestination);
return 0;
}
心得:
char*转DWORD:dwData = *(DWORD*)pbBuffer;
DWORD转char*:pbBuffer = (char *) &dwData;
版权声明:本文由作者Tony Qu原创, 未经作者同意必须保留此段声明,且在文章页面明显位置给出原文连接,否则视为侵权。