private function _create_captcha()
 {
     $fonts = array(public_path() . '/fonts/VeraBd.ttf', public_path() . '/fonts/VeraIt.ttf', public_path() . '/fonts/Vera.ttf');
     $cap = new Util_Captcha($fonts, 130, 30);
     $cap->setNumChars(4);
     $cap->Create();
     Session::put('myCaptchaCode', $cap->sCode);
     Session::put('myCaptchaCodeTime', time());
 }