java - Rijndael AES、addRoundKey、异或十六进制字符串并将它们存储为字节

Question

/*keyArray contains a line of cipherkey, and inputArray contains a text that is being encrypted.*/
public static void addRoundKey() {
        String keyEle = "";
        String inputEle = "";
        String result = "";
        for(int col=0; col<4; col++) {
            for(int row = 0; row<4; row++) {                
                keyEle = Integer.toHexString(keyArray[row][col] & 0xff);
                inputEle = Integer.toHexString(inputArray[row][col] & 0xff);
                if(keyEle.equals("0")) {
                    keyEle = "00";
                }
                if(inputEle.equals("0")) {
                    inputEle = "00";
                }
                BigInteger keyNum = new BigInteger(keyEle,16);
                BigInteger inputNum = new BigInteger(inputEle, 16);
                result = keyNum.xor(inputNum).toString();
                System.out.println("result = " + result);
                keyArray[row][col] = Byte.valueOf(result, 16); 
                //The above line causes Exception in thread "main" java.lang.NumberFormatException: Value out of range. Value:"99" Radix:16`

                //keyArray[row][col]  = (byte) (Integer.parseInt(result) & 0xff);           
            }
        }
    }

我认为 addRoundKey 步骤从我尝试加密的每个 key 和文本中获取一列，然后对它们进行异或，对吧？

所以，这就是我的实现，我明白为什么会出现“值超出范围”错误，这是因为 byte 接受的数字范围是 -128 到 127，对吗？

但我不太确定如何解决它。我无法更改 keyArray 的类型，即 Byte。

Answer 1

换行

keyArray[row][col] = Byte.valueOf(result, 16);

到

keyArray[row][col] = (byte) Integer.valueOf(result, 16).intValue();

编辑
甚至更短，正如 Bohemian 的答案中正确所述:

keyArray[row][col] = (byte) Integer.parseInt(result, 16);