RSA加密算法的C语言实现

////  main.cpp//  RSA////  Created by liujan on 10/21/14.//  Copyright (c) 2014 liujan. All rights reserved.//#include <iostream>#include "cmath"using namespace std;long long p = 1949, q = 3413;long long N = p * q;long long e = 13007, d = 511;//对a的b次幂取模 m（大数取模）long long Mod(long long a, long long  b, long long m){    long long r = 1;    for (long long j = 0; j < b; j++){        r = (r * a) % m;            }    return r;}//对输入信息进行rsa编码long long * rsaEncode(string message){    size_t length = message.length();    long long *ascii = new long long[length]; //存储信息的每个字符    long long *code = new long long[length];  //存储每个字符的rsa编码    for (size_t i = 0; i < length; i++){        ascii[i] = message[i];    }     for (size_t i = 0; i < length; i++){        code[i] = Mod(ascii[i], e, N ); //C=M^e (modN)    }        return code;}//根据rsa编码得到原来的信息string rsaDecode(long long code[], size_t n){    long long  *ascii = new long long[n];    string message = "";    for (size_t i = 0; i < n; i++){        ascii[i] = Mod(code[i], d, N); //M=C^d (modN)        message += ((char)(ascii[i]));    }    return message;}int main(int argc, const char * argv[]) {    string message = "Hello World!";    size_t length = message.length();    long long *a = rsaEncode(message);            string newmessage = rsaDecode(a, length);    cout << newmessage << endl;        return 0;}