public function isValidHash() : Bool
    {
        $hash   = $_POST['HASHPARAMS'];
        $hashEx = explode(':', $hash);
        $real   = NULL;

        foreach( $hashEx as $part )
        {
            if( ! empty($_POST[$part]) )
            {
                $real .= $_POST[$part];
            }
        }

        return $real === $_POST['HASHPARAMSVAL'] && $_POST['HASH'] === base64_encode(pack('H*',sha1($real . $_POST['storeKey'])));
    }