C++实现仿射加密法

创建Crypt.h头文件

#include <string>
#include <string.h>
using   namespace   std;

const   string  SYMBOL="ABCDEFGHIJKLMNOPQRSTUVWXYZ";

string  affineEncrypt(const char *data,int keyA,int keyB);//声明函数



string  affineEncrypt(const char *data,int keyA,int keyB)//实习函数
{
    string  result;
    int     len = strlen(data);
    for(int i=0;i<len;i++)
    {
        int pos = SYMBOL.find(data[i]);
        if(pos!=-1)
        {
            int offset = (keyA*pos+keyB)%26;
            result+=SYMBOL[offset];

        }else{
            result+=data[i];
        }
    }
    return result;
}

主程序“

#include <iostream>
#include <string>
#include "Crypt.h"
int main()
{
    char    data[]="THE NATIONAL SECURITY AGENCY";//明文

    string ret = affineEncrypt(data,11,23);//加密明文

    cout << ret << endl;//输出密文

    return 0;  
}