int prga(int *S, int *numbers, int len) {
  int i = -1, j = 0;
  int t;
  char out;
  int keys[len];
  cout << "Start PRGA" << endl;
  int count = 0;
  while(count < len) {
    i = (i + 1) % 256;
    j = (j + *(S + i)) % 256;
    swap(S, i, j);
    t = *(S + j) + *(S + i) % 256;
    keys[count] = *(S + t) % 256;
    count++;
  }
  for(i = 0; i < len; i++) {
    printf("%d", keys[i] ^ *(numbers + i));
  }
}