uggest change for security concern

[YYTVicky]

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[YYTVicky]

Hi,
we commend the key should be random generated for security reason, we have a recommend code patch:
SecureRandom random = new SecureRandom();
String key= String.valueOf(random.nextInt());
byte[] key = defaultKey.getBytes();
key = Arrays.copyOf(keyBytes,24);
Hope it can helps and looking forward to hearing any feedback from you!