#include<conio.h>
char encrypt(char ch,int n)/*加密函数，把字符向右循环移位n*/
{
while(ch>='A'&&ch<='Z')
{
return ('A'+(ch-'A'+n)%26);
}
while(ch>='a'&&ch<='z')
{
return ('a'+(ch-'a'+n)%26);
}
return ch;
}
void menu()/*菜单，1.加密，2.解密，3.暴力破解，密码只能是数字*/
{
clrscr();
printf("/n===============================================================================");
printf("/n1.Encrypt the file");
printf("/n2.Decrypt the file");
printf("/n3.Force decrypt file");
printf("/n4.Quit/n");
printf("===============================================================================/n");
printf("Please select a item:");
return;
}
void logo()/*显示版权信息*/
{
printf("/nZhensoft Encryption [Version:1.0.0]");
printf("/nCopyright (C) 2004 Zhensoft Corp./n");
printf("/nhttp://www.zhensoft.com/n");
return;
}
main()
{
int i,n;
char ch0,ch1;
FILE *in,*out;
char infile[20],outfile[20];
textbackground(BLACK);
textcolor(LIGHTGREEN);
clrscr();
logo();
sleep(3);/*等待3秒*/
menu();
ch0=getch();
while(ch0!='4')
{
if(ch0=='1')
{
clrscr();
printf("/nPlease input the infile:");
scanf("%s",infile);/*输入需要加密的文件名*/
if((in=fopen(infile,"r"))==NULL)
{
printf("Can not open the infile!/n");
printf("Press any key to exit!/n");
getch();
exit(0);
}
printf("Please input the key:");
scanf("%d",&n);/*输入加密密码*/
printf("Please input the outfile:");
scanf("%s",outfile);/*输入加密后文件的文件名*/
if((out=fopen(outfile,"w"))==NULL)
{
printf("Can not open the outfile!/n");
printf("Press any key to exit!/n");
fclose(in);
getch();
exit(0);
}
while(!feof(in))/*加密*/
{
fputc(encrypt(fgetc(in),n),out);
}
printf("/nEncrypt is over!/n");
fclose(in);
fclose(out);
sleep(1);
}
if(ch0=='2')
{
clrscr();
printf("/nPlease input the infile:");
scanf("%s",infile);/*输入需要解密的文件名*/
if((in=fopen(infile,"r"))==NULL)
{
printf("Can not open the infile!/n");
printf("Press any key to exit!/n");
getch();
exit(0);
}
printf("Please input the key:");
scanf("%d",&n);/*输入解密密码（可以为加密时候的密码）*/
n=26-n;
printf("Please input the outfile:");
scanf("%s",outfile);/*输入解密后文件的文件名*/
if((out=fopen(outfile,"w"))==NULL)
{
printf("Can not open the outfile!/n");
printf("Press any key to exit!/n");
fclose(in);
getch();
exit(0);
}
while(!feof(in))
{
fputc(encrypt(fgetc(in),n),out);
}
printf("/nDecrypt is over!/n");
fclose(in);
fclose(out);
sleep(1);
}
if(ch0=='3')
{
clrscr();
printf("/nPlease input the infile:");
scanf("%s",infile);/*输入需要解密的文件名*/
if((in=fopen(infile,"r"))==NULL)
{
printf("Can not open the infile!/n");
printf("Press any key to exit!/n");
getch();
exit(0);
}
printf("Please input the outfile:");
scanf("%s",outfile);/*输入解密后文件的文件名*/
if((out=fopen(outfile,"w"))==NULL)
{
printf("Can not open the outfile!/n");
printf("Press any key to exit!/n");
fclose(in);
getch();
exit(0);
}
for(i=1;i<=25;i++)/*暴力破解过程，在察看信息正确后，可以按'Q'或者'q'退出*/
{
rewind(in);
rewind(out);
clrscr();
printf("===============================================================================/n");
printf("The outfile is:/n");
printf("===============================================================================/n");
while(!feof(in))
{
ch1=encrypt(fgetc(in),26-i);
putch(ch1);
fputc(ch1,out);
}
printf("/n===============================================================================/n");
printf("The current key is: %d /n",i);/*显示当前破解所用密码*/
printf("Press 'Q' to quit and other key to continue....../n");
printf("===============================================================================/n");
ch1=getch();
if(ch1=='q'||ch1=='Q')/*按'Q'或者'q'时退出*/
{
clrscr();
logo();
printf("/nGood Bye!/n");
fclose(in);
fclose(out);
sleep(3);
exit(0);
}
}
printf("/nForce decrypt is over!/n");
fclose(in);
fclose(out);
sleep(1);
}
menu();
ch0=getch();
}
clrscr();
logo();
printf("/nGood Bye!/n");
sleep(3);
getch();
}