code: static SecretKey unwrap(SecretKey kek, byte[] wrappedKey, String wrappedKeyAlgorithm, int wrappedKeyType) throws InvalidKeyException {
  		final Cipher cipher = CipherSupplier.RFC3394_KEYWRAP.forUnwrapping(kek);
  		try {
  			return (SecretKey) cipher.unwrap(wrappedKey, wrappedKeyAlgorithm, wrappedKeyType);
  		} catch (NoSuchAlgorithmException e) {
  			throw new IllegalArgumentException("Invalid algorithm: " + wrappedKeyAlgorithm, e);
  		}
  	}
docs: visible for testing