public static function generate($mixed=null) {
		// create a sha1 signature of the array with a salt
		$hash = hash(
			Config::get('keys', 'algo'),
			json_encode(array($mixed, Config::get('keys', 'salt')), JSON_NUMERIC_CHECK)
		);
		// get last 10 and first 10 chars together, convert to uppercase, return the key
		return(strtoupper(substr($hash, -10) . substr($hash, 0, 10)));
	}