code: protected function generateCaptcha()
  	{
  		if ($this->arrCaptcha)
  		{
  			return;
  		}
  
  		$int1 = random_int(1, 9);
  		$int2 = random_int(1, 9);
  
  		$this->arrCaptcha = array
  		(
  			'int1' => $int1,
  			'int2' => $int2,
  			'sum' => $int1 + $int2,
  			'key' => $this->strCaptchaKey,
  			'hashes' => $this->generateHashes($int1 + $int2)
  		);
  	}
docs: Generate the captcha values