Question

我正在编写一个代码，用于加密和解密消息（使用DES算法），这两条消息都将显示在对话框中。但是当我运行代码时，我得到了nullPointerException。在调试代码后，我意识到空数据被存储为'iv'。这是我的代码： -

import javax.crypto.spec.*;
import javax.crypto.*;
import javax.swing.*;
public class des 
{
    public static void main(String ar[]) throws Exception
    {
        KeyGenerator keygen=KeyGenerator.getInstance("DES");
        SecretKey secretkey=keygen.generateKey();
        Cipher cip=Cipher.getInstance("DES");

        String inputText=JOptionPane.showInputDialog("Give input:");

        byte[] iv=cip.getIV();
        IvParameterSpec ps=new IvParameterSpec(iv);

        cip.init(Cipher.ENCRYPT_MODE,secretkey);
        byte[] encrypted=cip.doFinal(inputText.getBytes());

        cip.init(Cipher.DECRYPT_MODE,secretkey,ps);
        byte[] decrypted=cip.doFinal(encrypted);

        JOptionPane.showMessageDialog(null,"Encrypted :"+new String(encrypted)+"\n Decrypted :"+new String(decrypted));
        System.exit(0);
    }
}

Answer 1

您不需要IvParameterSpec来解密密钥。

工作代码：

public class des {

    public static void main(String[] args) throws Exception {
        KeyGenerator keygen=KeyGenerator.getInstance("DES");
        SecretKey secretkey=keygen.generateKey();
        Cipher encrypter=Cipher.getInstance("DES");
        Cipher decrypter=Cipher.getInstance("DES");

        String inputText=JOptionPane.showInputDialog("Give input:");

        encrypter.init(Cipher.ENCRYPT_MODE,secretkey);
        byte[] encrypted=encrypter.doFinal(inputText.getBytes());

        decrypter.init(Cipher.DECRYPT_MODE,secretkey);
        byte[] decrypted=decrypter.doFinal(encrypted);

        JOptionPane.showMessageDialog(null,"Encrypted :"+new String(encrypted)+"\n Decrypted :"+new String(decrypted));
        System.exit(0);

    }

}

bytes [] getIV（）方法返回null值

1 个答案: