*文件名:passwd.h
*创建者:ycj
*创建时间:2015-3-23
*文件说明:通过一种规则将字符串进行加密和解密
*************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *string_pass(char *password, char *string);
char *string_decode(char *pass_message, char *string_passwd);
/************************************************
*文件名:passwd.c
*创建者:ycj
*创建时间:2015-3-23
*文件说明:解密解密函数的实现
*************************************************/
#include "password.h"
//字符串加密
char *string_pass(char *pass_message, char *string_passwd)
{
int messagelength = strlen(pass_message);//获取加密信息的长度
int stringlength = strlen(string_passwd);//获取字符串长度(加密内容)
if (stringlength % messagelength == 0)//整除的情况
{
int count = stringlength / messagelength;//循环次数
for (int i = 0; i < count; i++)
{
for (int j = 0; j < messagelength; j++)
{
string_passwd[messagelength * i + j] ^= pass_message[j];
}
}
}
else
{
int count = stringlength / messagelength;//循环次数
for (int i = 0; i < count; i++)
{
for (int j = 0; j < messagelength; j++)
{
string_passwd[messagelength * i + j] ^= pass_message[j];
}
}
int lastlength = stringlength % messagelength;//剩下的长度
for (int i = 0; i < lastlength; i++)
{
string_passwd[(stringlength / messagelength) * messagelength + i] ^= pass_message[i];
}
}
return string_passwd;
}
//解密(与加密一样,异或两次得到本身)
char *string_decode(char *pass_message, char *string_passwd)
{
int messagelength = strlen(pass_message);//获取加密信息的长度
int stringlength = strlen(string_passwd);//获取字符串长度(加密内容)
if (stringlength % messagelength == 0)//整除的情况
{
int count = stringlength / messagelength;//循环次数
for (int i = 0; i < count; i++)
{
for (int j = 0; j < messagelength; j++)
{
string_passwd[messagelength * i + j] ^= pass_message[j];
}
}
}
else
{
int count = stringlength / messagelength;//循环次数
for (int i = 0; i < count; i++)
{
for (int j = 0; j < messagelength; j++)
{
string_passwd[messagelength * i + j] ^= pass_message[j];
}
}
int lastlength = stringlength % messagelength;//剩下的长度
for (int i = 0; i < lastlength; i++)
{
string_passwd[(stringlength / messagelength) * messagelength + i] ^= pass_message[i];
}
}
return string_passwd;
}
/************************************************
*文件名:test.c
*创建者:ycj
*创建时间:2015-3-23
*文件说明:测试
*************************************************/
#include "password.h"
void main()
{
char string[20] = "abcdefghi";
char *password = "123";
printf("%s\n", string_pass(password, string));
printf("%s\n", string_decode(password, string));
system("pause");
}