protected byte[] decrypt(RSAPrivateKey rsaPrivateKey, byte[] obj){
		if (rsaPrivateKey != null) {
			try {
				Cipher cipher = Cipher.getInstance("RSA");
				cipher.init(Cipher.DECRYPT_MODE, rsaPrivateKey);
				return cipher.doFinal(obj);
			} catch (NoSuchAlgorithmException e) {
				e.printStackTrace();
			} catch (NoSuchPaddingException e) {
				e.printStackTrace();
			} catch (InvalidKeyException e) {
				e.printStackTrace();
			} catch (IllegalBlockSizeException e) {
				e.printStackTrace();
			} catch (BadPaddingException e) {
				e.printStackTrace();
			}
		}
		return null;
	}