【加密解密】对字符串的加密解密

来源：互联网发布：进销存软件免费版app 编辑：程序博客网时间：2024/05/01 05:16

</pre><pre code_snippet_id="1666199" snippet_file_name="blog_20160429_2_7838133" name="code" class="cpp"><span style="font-size:24px;">字符串 加密解密的入门练习，</span>

#include<stdio.h>#include<stdlib.h>//按照密码加密//文件加密//字符串加密char *stringEncrypt(char *password, char *string);char *stringDecode(char *password, char *string);#include "passw.h"//异或的加密解密函数是一样的//字符串加密char *stringEncrypt(char *password, char *string){int passLength = strlen(password);//获取加密长度int stringLength = strlen(string);//获取字符串长度if (stringLength%passLength == 0)//字符串长度是密码长度的整数倍{int times = stringLength/passLength;for (int i = 0; i < times; i++){for (int j = 0; j < passLength; j++){string[i*passLength+j] ^= password[j];//这里的下标计算画图很容易理解}}}else{int times = stringLength / passLength;for (int i = 0; i < times; i++){for (int j = 0; j < passLength; j++){string[i*passLength + j] ^= password[j];}}int lastLength = stringLength%passLength;//不能整除的，也就是余数长度for (int i = 0; i < lastLength; i++){string[passLength*(stringLength / passLength) + i] ^= password[i];//这里的解密要从前边已经整除完成的后一个位置开始，//假如说stringLength = 10,passLength = 4;那么除不尽的加密就从下标8开始，//(10 / 4)*4 = 8.}}return string;}//字符串解密char *stringDecode(char *password, char *string){int passLength = strlen(password);//获取加密长度int stringLength = strlen(string);//获取字符串长度if (stringLength % passLength == 0)//字符串长度是密码长度的整数倍{int times = stringLength/passLength;for (int i = 0; i < times; i++){for (int j = 0; j < passLength; j++){string[i*passLength + j] ^= password[j];}}}else{int times = stringLength / passLength;for (int i = 0; i < times; i++){for (int j = 0; j < passLength; j++){string[i*passLength + j] ^= password[j];}}int lastLength = stringLength%passLength;//不能整除的，也就是余数长度for (int i = 0; i < lastLength; i++){string[passLength*(stringLength / passLength) + i] ^= password[i];//这里的解密要从前边已经整除完成的后一个位置开始，//假如说stringLength = 10,passLength = 4;那么除不尽的加密就从下标8开始，//(10 / 4)*4 = 8.}}return string;}//测试代码#include<stdio.h>#include<stdlib.h>#include "passw.h"void main(){char str[20] = "abcdefghijk";char *password = "123";printf("%s\n", stringEncrypt(password, str));printf("%s\n", stringDecode(password, str));system("pause");}

0 0