java - 在客户端-服务器应用程序中使用 RSA 时为 "UnsupportedEncodingException: SHA"

Question

我正在开发一个 Java 即时通讯应用程序。我尝试实现 Demonstrate the use of RSA Public-key system to exchange messages that achieve confidentiality and integrity/authentication 中讨论的 RSA 算法。提供了解决方案，但收到的消息未正确解密。

堆栈跟踪:

java.io.UnsupportedEncodingException: SHA
    at java.lang.StringCoding.decode(StringCoding.java:190)
    at java.lang.String.<init>(String.java:426)
    at java.lang.String.<init>(String.java:491)
    at mychatappp.networking.MessageListener.decryptMessage(MessageListener.java:87)
    at mychatappp.networking.MessageListener.run(MessageListener.java:115)

服务器端运行方法:

ServerSocket server;
int listenPort = 8877;
WritableGUI gui;
LoginScreen sc = new LoginScreen();

public MessageListener(WritableGUI gui, int port){
    this.listenPort = port;
    this.gui = gui;
    try {
        server = new ServerSocket(port);
    } catch (IOException ex) {
        Logger.getLogger(MessageListener.class.getName()).log(Level.SEVERE, null, ex);
    }
}
public void decryptMessage(InputStream inStream) throws IOException, NoSuchAlgorithmException
{
    try {

        //Create the Data input stream from the socket
        DataInputStream dis = new DataInputStream(inStream);

        //Get the key
        ObjectInputStream in = new ObjectInputStream(new FileInputStream("KeyFile.xx"));

        PrivateKey privatekey = (PrivateKey) in.readObject();
        System.out.println("Key Used: " + in.toString());
        in.close();

        //Initiate the cipher
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");                        
        cipher.init(Cipher.DECRYPT_MODE,privatekey);

        int len = dis.readInt();
        byte[] encryptedMsg = new byte[len];
        dis.readFully(encryptedMsg);         

        System.out.println("Server - Msg Length: " + len);
        System.out.println("Server - Encrypted: " + asHex(encryptedMsg));

        // -Print out the decrypt String to see if it matches the original message.
        byte[] plainText = cipher.doFinal(encryptedMsg);
        System.out.println("Decrypted Message: " + new String(plainText, "SHA"));


    } catch (Exception e) {
        e.printStackTrace();
    }
}

//Function to make the bytes printable (hex format)
public static String asHex(byte buf[]) {
    StringBuilder strbuf = new StringBuilder(buf.length * 2);
    int i;
    for (i = 0; i < buf.length; i++) {
        if (((int) buf[i] & 0xff) < 0x10) {
            strbuf.append("0");
        }
        strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
    }
    return strbuf.toString();
}

@Override
public void run() {
    Socket clientSocket;

    try {
        while((clientSocket = server.accept()) != null){
            InputStream is = clientSocket.getInputStream();
            decryptMessage(is);
            BufferedReader br = new BufferedReader(new InputStreamReader(is)); 
            String line = br.readLine();
            if(line != null){
                gui.write(line);
            }
        }

我哪里出错了？

Answer 1

问题出在这个代码段new String(plainText, "SHA")中。 SHA 不是字符编码。我不知道您的字符串是如何编码的(即字符如何转换为字节，反之亦然)，但您可能需要这里的 "UTF-8" 。