public static NormalKey createRandom(EncryptionAlgorithmPB algorithm) {
        byte[] plainKey;
        if (algorithm == EncryptionAlgorithmPB.AES_128) {
            plainKey = EncryptionUtil.genRandomKey(16);
        } else {
            throw new IllegalArgumentException("Unsupported algorithm: " + algorithm);
        }
        return new NormalKey(algorithm, plainKey, null);
    }
@Test
    public void testCreateRandom() {
        NormalKey key = NormalKey.createRandom();
        assertNotNull(key);
        assertNotNull(key.getPlainKey());
        assertEquals(EncryptionAlgorithmPB.AES_128, key.getAlgorithm());
    }