将 Key 转换为 String 并转换回 Key Java

Posted 2023-02-22

【中文标题】将 Key 转换为 String 并转换回 Key Java

【英文标题】：Converting Key to String and back to Key Java

【发布时间】：2012-09-06 03:00:11

【问题描述】：

所以我正在尝试将 Key 转换为字符串，以便可以使用 System.out 显示它，然后我想将其转换回 Key。我可以使用 BASE64Encoder 将其转换为字符串，但在将其转换回来时遇到问题。这是我的源代码：

    public class Encryption extends Applet 
    Key keyOrig;
    BASE64Decoder decoder = new BASE64Decoder();
    BASE64Encoder encoder = new BASE64Encoder();

    public void init() 
        try 
            keyOrig = generateKey();

            String keyString = encoder.encode(keyOrig.getEncoded());
            System.out.println("Key: "+keyString);

            Key key = new SecretKeySpec(keyString.getBytes(),0,keyString.getBytes().length, "DES");     

            String message = "This is hacker proof!";
            System.out.println("Message is: "+message);

            String encryptedMessage = encrypt(message,key);
            System.out.println("Message encrypted: "+ encryptedMessage);

            String decryptedMessage = decrypt(encryptedMessage,key);
            System.out.println("Message decrypted: "+ decryptedMessage);



         catch (Exception e) 
            e.printStackTrace();
        
    

    public Key generateKey() throws NoSuchAlgorithmException 
        KeyGenerator generator;
        generator = KeyGenerator.getInstance("DES");
        generator.init(new SecureRandom());
        return keyOrig = generator.generateKey();
    

    @SuppressWarnings("unused")
    public String encrypt(String message, Key key)
            throws IllegalBlockSizeException, BadPaddingException,
            NoSuchAlgorithmException, NoSuchPaddingException,
            InvalidKeyException, UnsupportedEncodingException 
        // Get a cipher object.
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, key);

        // Gets the raw bytes to encrypt, UTF8 is needed for
        // having a standard character set
        byte[] stringBytes = message.getBytes("UTF8");

        // encrypt using the cypher
        byte[] raw = cipher.doFinal(stringBytes);

        // converts to base64 for easier display.
        @SuppressWarnings("restriction")
        BASE64Encoder encoder = new BASE64Encoder();
        String base64 = encoder.encode(raw);

        return base64;
    

    public String decrypt(String encrypted, Key key) throws InvalidKeyException,
            NoSuchAlgorithmException, NoSuchPaddingException,
            IllegalBlockSizeException, BadPaddingException, IOException 

        // Get a cipher object.
        Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, key);

        // decode the BASE64 coded message
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] raw = decoder.decodeBuffer(encrypted);

        // decode the message
        byte[] stringBytes = cipher.doFinal(raw);

        // converts the decoded message to a String
        String clear = new String(stringBytes, "UTF8");
        return clear;
    

【参考方案1】：

您永远不会使用您的BASE64Decoder 对您的字符串进行 un-base-64。

替换这个：

        Key key = new SecretKeySpec(keyString.getBytes(),0,keyString.getBytes().length, "DES");     

与

        byte[] encodedKey = decoder.decodeBuffer(keyString);
        Key key = new SecretKeySpec(encodedKey,0,encodedKey.length, "DES");