網上看到兩種方法：
1.SecretKeySpec skeySpec = new SecretKeySpec(getRawKey(key), "AES");
private static byte[] getRawKey(byte[] seed) throws Exception {
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
sr.setSeed(seed);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
return raw;
}
紅色的部分為注意項，不能寫為SecureRandom sr = SecureRandom.getInstance("SHA1PRNG"）；
2.Cipher cipher = Cipher.getInstance("AES"); ---------4.3以上有bug
修改為
Cipher cipher = Cipher.getInstance("AES/ECB/ZeroBytePadding");