byte[] iv = new byte[GCM_IV_SIZE];
            secureRandom.nextBytes(iv);

            // Setup cipher
            Cipher cipher = Cipher.getInstance(ENCRYPTION_ALGORITHM);
            GCMParameterSpec gcmSpec = new GCMParameterSpec(GCM_TAG_SIZE, iv);
            cipher.init(Cipher.ENCRYPT_MODE, masterKey, gcmSpec);

            // Encrypt
            byte[] ciphertext = cipher.doFinal(plaintextBytes);

            final SecretKeySpec keySpec = new SecretKeySpec(keyCopy, "AES");
            final Cipher cipher = Cipher.getInstance(transformation);
            final GCMParameterSpec gcmSpec = new GCMParameterSpec(getAuthTagLength() * 8, nonce);

            cipher.init(encrypt ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE, keySpec, gcmSpec);
            return cipher;
        } finally {