#include <ctime>

#include <iostream>
#include <cstdlib>

using namespace std;
struct public_key
{
	int  n;
	int  x;
};
struct private_key
{
	int p;
	int q;
};
int  power(int x,int y,int m)//cal x^y%m
{
	if(y==0)return 1%m;
	int  ret=x%m;
	for(int i=0;i<y-1;i++)
		ret=(ret*x)%m;
	return ret;
}
int get_x(int p,int q)
{
	for(int i=1;i<p*q;i++)
	{
		if (power(i,(p-1)/2,p)==p-1&&power(i,(q-1)/2,q)==q-1)
		{
			cout<<"get x:"<<i<<endl;
			return i;
		}
	}
}
void get_key(public_key* bk,private_key* rk,int p,int q)
{
	bk->n=p*q;
	bk->x=get_x(p,q);
	rk->p=p;
	rk->q=q;
}
int get_random(int n)
{
	srand(unsigned(time(0)));
	int ret=rand()%1000;
	int max,min;
	if(ret>=n)
	{
		max=ret;
		min=n;
	}
	else 
	{
		max=n;
		min=ret;
	}
	while(min)
	{
		int tmp=max%min;
		if(tmp==1)return  ret;
		max=min;
		min=tmp;
	}
}
int encrypt(int src,int n,int x)
{
	int y=get_random(n);
	cout<<"get y:"<<y<<endl;
	return (power(y,2,n)*power(x,src,n))%n;
}
int decode(int src,int p,int q)
{
	int cp=power(src,(p-1)/2,p);
	int cq=power(src,(q-1)/2,q);
	cout<<"c/p="<<cp<<endl;
	cout<<"c/q="<<cq<<endl;
	if(cp==1&&cq==1) 
		return 0;
	else 
		return 1;
}

int main()
{
	public_key* bk=new public_key;
	private_key* rk=new private_key;
	int p=613,q=827;
	get_key(bk,rk,p,q);
	int src=1;
	cout<<"1:\n";
	int enc=encrypt(src,bk->n,bk->x);
	cout<<"encrypt:"<<enc<<endl;
	cout<<"m':"<<decode(enc,rk->p,rk->q)<<endl;
	src=0;
	cout<<"0:\n";
	enc=encrypt(src,bk->n,bk->x);
	cout<<"encrypt:"<<enc<<endl;
	cout<<"m':"<<decode(enc,rk->p,rk->q)<<endl;
	return 0;
}