java - 在 Java 中重用 SecretKey

Question

我试图简单地加密一些文本，将其保存在文本文件中，然后加载/解密它。

使用Java网站上的教程，我一直使用的代码:

public class MainClass {
  public static void main(String args[]) throws Exception {
    KeyGenerator kg = KeyGenerator.getInstance("DES");
    kg.init(new SecureRandom());
    SecretKey key = kg.generateKey();
    SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
    Class spec = Class.forName("javax.crypto.spec.DESKeySpec");
    DESKeySpec ks = (DESKeySpec) skf.getKeySpec(key, spec);
    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("keyfile"));
    oos.writeObject(ks.getKey());

    Cipher c = Cipher.getInstance("DES/CFB8/NoPadding");
    c.init(Cipher.ENCRYPT_MODE, key);
    CipherOutputStream cos = new CipherOutputStream(new FileOutputStream("ciphertext"), c);
    PrintWriter pw = new PrintWriter(new OutputStreamWriter(cos));
    pw.println("Stand and unfold yourself");
    pw.close();
    oos.writeObject(c.getIV());
    oos.close();
  }
}

保存加密的文本文件。

我一直在使用代码:

public class MainClass {
  public static void main(String args[]) throws Exception {
    ObjectInputStream ois = new ObjectInputStream(new FileInputStream("keyfile"));
    DESKeySpec ks = new DESKeySpec((byte[]) ois.readObject());
    SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
    SecretKey key = skf.generateSecret(ks);

    Cipher c = Cipher.getInstance("DES/CFB8/NoPadding");
    c.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec((byte[]) ois.readObject()));
    CipherInputStream cis = new CipherInputStream(new FileInputStream("ciphertext"), c);
    BufferedReader br = new BufferedReader(new InputStreamReader(cis));
    System.out.println(br.readLine());
  }
}

加载并解密文本文件。这给出了输出:

Stand and unfold yourself!

然后，我更改了第一个函数，以便它重新使用相同的 SecretKey，而不是生成新的 SecretKey。

   ObjectInputStream ois = new ObjectInputStream(new FileInputStream("keyfile"));
    DESKeySpec ks = new DESKeySpec((byte[]) ois.readObject());
    SecretKeyFactory skf = SecretKeyFactory.getInstance("DES");
    SecretKey key = skf.generateSecret(ks);

    Cipher c = Cipher.getInstance("DES/CFB8/NoPadding");
    c.init(Cipher.ENCRYPT_MODE, key);
    CipherOutputStream cos = new CipherOutputStream(new FileOutputStream("ciphertext"), c);
    PrintWriter pw = new PrintWriter(new OutputStreamWriter(cos));
    pw.println("Stand and unfold yourself");
    pw.close();

但是，当我运行该程序时 - 输出是困惑的!我得到以下输出，而不是上面的输出

F{�&;�d unfold yourself

Answer 1

您没有使用文件中的 IV 初始化加密密码。