public static String decode(X509Certificate x509) {
		List<String> result = new ArrayList<>();
		boolean[] usage = x509.getKeyUsage();
		if (usage == null) { return "<missing>"; }
		
		for (int i = 0; i < NAMES.length; i++) {
			if (i >= usage.length) break;
			if (usage[i]) {
				result.add(NAMES[i]);
			}
		}
		return result.toString();
	}