Thread: XOR encryption problem

Im wanting to learn basic encryption to stop editing of .txt files for my game. But I have run into a problem my program crashes ! I just can't find the problem

Code:

#include <iostream>
#include <cstring>
#include <windows.h>
using namespace std;

void Encode_m(char message[256],char key [256])
{
	for (int i=0;i<strlen(message);i++)
	{
		message[i] = message[i]^key[i];
		cout << message[i];
	}
}
int main()
{
	Encode_m("This is a test","ABCDEFG");
	system("pause");
}