Question

我收到此警告：

javax.crypto.BadPaddingException：给定最后一个块，未正确填充。如果在解密过程中使用了错误的密钥，则会出现此类问题。

任何想法是什么原因造成的？这是我的加密和解密代码。我在StackOverflow上查看了各种不同的答案，但找不到实际可行的答案。

    private static Cipher ecipher;
private static Cipher dcipher;

private static SecretKey key;

public static void Menu() {
    try {

        // generate secret key using DES algorithm
        key = KeyGenerator.getInstance("DES").generateKey();

        ecipher = Cipher.getInstance("DES");
        dcipher = Cipher.getInstance("DES");

        // initialize the ciphers with the given key
        ecipher.init(Cipher.ENCRYPT_MODE, key);

        dcipher.init(Cipher.DECRYPT_MODE, key);

    } catch (NoSuchAlgorithmException e) {
        System.out.println("No Such Algorithm:" + e.getMessage());
        return;
    } catch (NoSuchPaddingException e) {
        System.out.println("No Such Padding:" + e.getMessage());
        return;
    } catch (InvalidKeyException e) {
        System.out.println("Invalid Key:" + e.getMessage());
        return;
    }
}

public static String encrypt(String WordToEncrypt) {

    Menu();
    try {

        // encode the string into a sequence of bytes using the named charset
        // storing the result into a new byte array. 
        byte[] utf8 = WordToEncrypt.getBytes("UTF8");

        byte[] enc = ecipher.doFinal(utf8);

        // encode to base64
        enc = BASE64EncoderStream.encode(enc);
        System.out.println(new String(enc));

        return new String(enc);

    } catch (Exception e) {

        e.printStackTrace();

    }
    return null;
}

public static String decrypt(String WordToDecrypt) {
    Menu();
    try {
        // decode with base64 to get bytes
        byte[] dec = BASE64DecoderStream.decode(WordToDecrypt.getBytes());
        byte[] utf8 = dcipher.doFinal(dec);
        return new String(utf8, "UTF8");
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;

}

}

Answer 1

您分别在加密代码和解密代码中调用Menu。由于您随机生成用于加密和解密的密钥，因此密钥将有所不同，并且代码将失败。

不要保持Cipher实例在周围，最好甚至不在字段中，但肯定不在类字段中。 DES很旧；太太老了。使用AES-使用DES并不比AES容易。

Java-解密：javax.crypto.BadPaddingException

1 个答案: