用C++编写文件的加密和解密

#include "stdio.h"
#include "stdlib.h"
#include "time.h"
#include "string.h"
#include "define.h"
#include "unistd.h"

/* This function is used to show the instruction. */
void vInstruction(void)
{
printf("This program can produce a 512 byte key-file");
printf(" and/or protect the selected file.\n");
printf("Copyright 2006-2007 (C) Northeastern University at Qinhuangdao\n");
printf(" All Rights Reserved\n\n");
printf("CODETEST [-P] [-U] [-C] [-K:keyfile] [-S:source]/[-D:destination]\n\n");
printf(" -s:source Specifies the file to be coded or decoded.\n");
printf(" [-p] Use this parameter to protect your file.\n");
printf(" [-u] Use this parameter to unprotect your file.\n");
printf(" [-c] Use this parameter to creat your key file.\n");
printf(" -k:keyfile Specifies the directory and/or filename of the key file.\n");
printf(" -d:destination Specifies the directory and/or filename for the new file.\n\n");
printf("The switch -p may be preset in the program ,so I advise you that before ");
printf("you use this program , make sure that you did know what you are doing.");
printf("The producter \nrefuse to take any clear or potential responsibility for");
printf(" the correct or uncorre-ct use of this program.Have Fun and Good Luck.\n\n");
system("pause");
exit(0);
}

/* This function is used to creat the key string */
void vCreatKey(char sTemp[])
{
int iNum,iTemp;
srand( (unsigned)time(NULL));
for (iNum = 0; iNum <= 511; iNum++)
while((iTemp = (char)(rand()%10))!=0x00)
sTemp[iNum] = iTemp;
}

/* This function is used to creat the key file in ascii mode */
int iSaveFile(char sFilePath[],char sKey[])
{
FILE *fpTemp;
int iNum=0;
if( ( fpTemp=fopen(sFilePath,"wb+") )==NULL)
{
printf("File Creat Error!");
return 0;
}
else
while(iNum<512)
{
putc(sKey[iNum],fpTemp);
iNum++;
}
fclose(fpTemp);
printf("Key File Has Been Created\n");
return 1;
}

/* This function is used to find the path of the orginal file. */
void vFindPath(char sTemp[])
{
int iNum;
for (iNum=strlen(sTemp);iNum>=0;iNum--)
{
if (sTemp[iNum]=='\\') break;
sTemp[iNum]='\0';
}
}

/* This function is used to find the real file name whitout path */
void vFindFileName(char sPath[],char sFilePreName[],char sFileLstName[])
{
char sOri[50];
int iNum,iNumB;
strcpy(sOri,sPath);
vFindPath(sPath);
for (iNum = strlen(sPath);iNum <= 50;iNum++)
{
if(sOri[iNum]=='.')
{
sFilePreName[iNum-strlen(sPath)] = '\0';
break;
}
sFilePreName[iNum-strlen(sPath)] = sOri[iNum];
};
iNumB=iNum+1;
for (iNum=iNum+1;iNum <= 50;iNum++)
{
sFileLstName[iNum-iNumB] = sOri[iNum];
if(sOri[iNum]=='\0')break;
};
}

/* This function is used to read file and save it to a string */
void vReadKeyFile(char sTemp[],char sKeyFilePath[])
{
FILE *fpTemp;
int iNum=0;
if( ( fpTemp=fopen(sKeyFilePath,"rb") )==NULL)
{
printf("File Read Error!");
}
else
{
for(iNum=0;iNum<=511;iNum++)
sTemp[iNum]=fgetc(fpTemp);
}
}

/* This function is used to protect or unprotect the file */
void vProtectFile(char sSrcFile[],char sDstFile[],char sKeyFile[])
{
FILE *fpTempA,*fpTempB;
int iNum;
char sTemp[512],cTemp;
vReadKeyFile(sTemp,sKeyFile);
if( (fpTempA = fopen(sSrcFile,"rb"))==NULL )
{
printf("Open Source File Error!");
exit(0);
}
else if( (fpTempB = fopen(sDstFile,"wb"))==NULL )
{
printf("Open Destination File Error!");
exit(0);
}
else
{
for(iNum=0;iNum<=511;iNum++)
{
cTemp=fgetc(fpTempA);
if(feof(fpTempA))
{
break;
}
fputc( (cTemp^sTemp[iNum]),fpTempB );
if(iNum==511)iNum=0;
}
fclose(fpTempA);
fclose(fpTempB);
}
}

/* This function is used to copy one file to a temp file */
void vCopyFile(char sSrcPath[],char sDstPath[])
{
FILE *fpTempA,*fpTempB;
char cTemp;
if ( (fpTempA=fopen(sSrcPath,"rb"))==NULL )
{
printf("Source File Open Error!");
exit(0);
}
else if ( (fpTempB=fopen(sDstPath,"wb"))==NULL )
{
printf("Temp File Creat Error!");
exit(0);
}
else
{
while(1)
{
cTemp=fgetc(fpTempA);
if(feof(fpTempA))break;
fputc(cTemp,fpTempB);
}
fclose(fpTempA);
fclose(fpTempB);
}
}

/* This is the Entry Point of the program */
int main(int argc, char **argv)
{
char cParameter,sSrcPath[50],sDstPath[50],sKeyPath[50];
char sTemp[512],sFilePreName[20],sFileLstName[6],sFileName[20];
char sSrcPathA[50],sSrcPathB[50],sFilePreNameA[50],sFileLstNameA[50];
int iCheck=0,iNum;
if (argc==1)vInstruction();
while( ( cParameter = getopt(argc,argv,"s:d:k:ucp") ) != -1 )
switch(cParameter)
{
case 's':
strcpy(sSrcPath,optarg);iCheck |= P_SRC; break;

case 'd':
strcpy(sDstPath,optarg);iCheck |= P_DST; break;

case 'k':
strcpy(sKeyPath,optarg);iCheck |= P_KEY; break;

case 'u':
iCheck |= P_UP; break;

case 'c':
iCheck |= P_CKEY; break;

case 'p':
iCheck |= P_PROTECT; break;

default:
iCheck = 0;
}

switch(iCheck)
{
case (P_CKEY):
vCreatKey(sTemp);
iSaveFile("key.sys",sTemp);
break;

case (P_CKEY|P_DST):
vCreatKey(sTemp);
iSaveFile(sDstPath,sTemp);
break;

case (P_SRC):
case (P_SRC|P_PROTECT):
vCreatKey(sTemp);
strcpy(sSrcPathA,sSrcPath);
vFindFileName(sSrcPath,sFilePreName,sFileLstName);
strcpy(sSrcPathB,sSrcPath);
strcpy(sFilePreNameA,sFilePreName);
strcpy(sKeyPath,strcat(sSrcPath,strcat(sFilePreName,".key")));
iSaveFile(sKeyPath,sTemp);
strcpy(sDstPath,sSrcPathA);
strcpy(sFilePreName,sFilePreNameA);
strcpy(sSrcPath,sSrcPathB);
strcpy(sFileName,strcat(sSrcPath,strcat(sFilePreName,".bak")));
vCopyFile(sSrcPathA,sFileName);
vProtectFile(sFileName,sDstPath,sKeyPath);
printf("Operation Down");
break;

case (P_SRC|P_UP|P_DST):
case (P_SRC|P_DST):
case (P_SRC|P_PROTECT|P_DST):
vCreatKey(sTemp);
strcpy(sSrcPathA,sSrcPath);
vFindFileName(sSrcPath,sFilePreName,sFileLstName);
strcpy(sSrcPathB,sSrcPath);
strcpy(sFilePreNameA,sFilePreName);
strcpy(sKeyPath,strcat(sSrcPath,strcat(sFilePreName,".key")));
iSaveFile(sKeyPath,sTemp);
strcpy(sFilePreName,sFilePreNameA);
strcpy(sSrcPath,sSrcPathB);
strcpy(sFileName,strcat(sSrcPath,strcat(sFilePreName,".bak")));
vCopyFile(sSrcPathA,sFileName);
vProtectFile(sFileName,sDstPath,sKeyPath);
printf("Operation Down");
break;

case (P_SRC|P_DST|P_KEY):
case (P_SRC|P_DST|P_KEY|P_UP):
case (P_SRC|P_DST|P_KEY|P_PROTECT):
strcpy(sSrcPathA,sSrcPath);
vFindFileName(sSrcPath,sFilePreName,sFileLstName);
strcpy(sFileName,strcat(sSrcPath,strcat(sFilePreName,".bak")));
vCopyFile(sSrcPathA,sFileName);
vProtectFile(sFileName,sDstPath,sKeyPath);
printf("Operation Down");
break;

case (P_SRC|P_KEY):
case (P_SRC|P_UP|P_KEY):
case (P_SRC|P_PROTECT|P_KEY):
strcpy(sSrcPathA,sSrcPath);
vFindFileName(sSrcPath,sFilePreName,sFileLstName);
strcpy(sDstPath,sSrcPathA);
strcpy(sFileName,strcat(sSrcPath,strcat(sFilePreName,".bak")));
vCopyFile(sSrcPathA,sFileName);
vProtectFile(sFileName,sDstPath,sKeyPath);
printf("Operation Down");
break;

default:
vInstruction();
}
return 0;
}