function validateCaptcha($fieldName, $params){
		$caseInsensitive = true;
		
		$val = $this->data[$this->name][$fieldName];
		
		if ($caseInsensitive) {
            $val = strtoupper($val);
        }
        
        //php-captcha.inc.php
        if(!defined('CAPTCHA_SESSION_ID'))
        	define('CAPTCHA_SESSION_ID', 'php_captcha');
         
         if (!empty($_SESSION[CAPTCHA_SESSION_ID]) && $val == $_SESSION[CAPTCHA_SESSION_ID]) {
            // clear to prevent re-use
            unset($_SESSION[CAPTCHA_SESSION_ID]);
            
            return true;
         }
         
         return false;
	}