RSA加密和解密实现

根据RSA一堆原理，写了个实现的代码，亲测可用，哈哈记录一下

#include 
#include 
#include 
using namespace std;
int exgcd(int a,int b,int & x,int & y){
	if(b == 0){
		x = 1;
		y = 0;
		return a;
	}
	int r = exgcd(b, a%b, x, y);
	int t = y;
	y = x - (a/b)*y;
	x = t;
	return r;
}
//快速幂
int PowerMod(int a, int b, int c)
{
  int ans = 1;
  a = a % c;
  while(b>0) {
    if(b % 2 == 1)
        ans = (ans * a) % c;
    b = b/2;
    a = (a * a) % c;
  }
  return ans;
}

long SKG(long p,long q,long e,long M)
{
    long N=p*q;
    long fN=(p-1)*(q-1);
    long C=1;
    C=PowerMod(M,e,N);
    return C;
}

long SKG_1(long p,long q,long e,long C)
{
    long N=p*q;
    long fN=(p-1)*(q-1);
    long M=1;
    int x,y;
    long d;
    exgcd(e,fN,x,y);
    d=x%fN;
    M=PowerMod(C,d,N);
    return M;
}



int main()
{
    long p,q,e,d,M,C;
    char i;
    printf("请选择加密或解密:加密请选择1，解密请选择2\n");
    i=getchar();
    if(i=='1')
    {
        printf("请依次输入p,q,e,M\n");
        scanf("%d%d%d%d",&p,&q,&e,&M);
        printf("%d\n",SKG(p,q,e,M));
    }

     if(i=='2')
    {
        printf("请依次输入p,q,e,C\n");
        scanf("%d%d%d%d",&p,&q,&e,&C);
        printf("%\d\n",SKG_1(p,q,e,C));
    }
    return 0;
}