linux 加密解密文件小程序

代码见下面，编译之后就可以用；建议放在bash下，或者添加环境变量。

使用方法：encrypt <文件名>。两次输入密码。加密密码与解密密码不一致解码后就不是原文件了！

#include <stdio.h>   
#include <stdlib.h>   
#include <string.h>   

int decrypt(FILE *in,FILE *out);  
int encrypt(FILE *in,FILE *out);  
int passlen;
char pass[105],passa[105];

int main(int argc,char **argv)  
{  
    if(argc != 2)  
    {  
        printf("
请输入文件名进行加密或者解密!
");  
        printf("    encrypt <inputfile>

");  
        exit(0);  
    }  
    while(1)
    {
        printf("Enter password:");
        system("stty -icanon");
        system("stty -echo");   
        scanf("%s",pass);
        system("stty icanon");
        system("stty echo");
        printf("
Enter password again:");
        system("stty -icanon");
        system("stty -echo");   
        scanf("%s",passa);
        system("stty icanon");
        system("stty echo");
        if(strcmp(pass,passa)==0) break;
        printf("
Password is inconsistent
");
    }
    printf("
");
    FILE *in = fopen(argv[1],"rb");  
    FILE *out = fopen("encrypt-tmp","w");  
    passlen=strlen(pass);
    char code=0xAA;
    for(int i=0;i<passlen;i++) pass[i]=pass[i]^code;
    if(in == NULL || out == NULL)  
    {  
        fprintf(stderr,"%s
","open file error!");  
        exit(1);  
    }  
    encrypt(in,out);  
    fclose(in);  
    fclose(out);
    remove(argv[1]);
    rename("encrypt-tmp",argv[1]);
    return 0;  
}  
int encrypt(FILE *in,FILE *out)  
{  
    if(in == NULL || out == NULL)  
    {  
        fprintf(stderr,"%s
","file error!
");  
        return -1;  
    }  
  
    char hex;  
    int i=0;
    while(fread(&hex,1,1,in))  
    {  
        char s=pass[i];
        hex = hex^s;  
        fwrite(&hex,1,1,out);  
        i++;
        i%=passlen;
    }  
    return 0;  
}