用java实现基于cs模式的sm4算法加解密软件实现

好的，以下是Java实现的基于cs模式的sm4算法加解密软件实现：

服务端代码：

import cn.com.sgcc.crypto.SM4;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.charset.StandardCharsets;

public class SM4Server {

    private static final int PORT = 8888;
    private static final String KEY = "1234567890abcdef";

    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(PORT);
        System.out.println("Server started, waiting for client connection...");
        while (true) {
            Socket socket = serverSocket.accept();
            System.out.println("Client connected: " + socket.getInetAddress().getHostAddress());
            new Thread(() -> {
                try {
                    DataInputStream dis = new DataInputStream(socket.getInputStream());
                    DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
                    while (true) {
                        int type = dis.readInt();
                        if (type == 0) {  // 加密
                            int length = dis.readInt();
                            byte[] data = new byte[length];
                            dis.readFully(data);
                            byte[] encryptedData = SM4.encrypt_ECB(data, KEY.getBytes(StandardCharsets.UTF_8));
                            dos.writeInt(encryptedData.length);
                            dos.write(encryptedData);
                            dos.flush();
                        } else if (type == 1) {  // 解密
                            int length = dis.readInt();
                            byte[] data = new byte[length];
                            dis.readFully(data);
                            byte[] decryptedData = SM4.decrypt_ECB(data, KEY.getBytes(StandardCharsets.UTF_8));
                            dos.writeInt(decryptedData.length);
                            dos.write(decryptedData);
                            dos.flush();
                        } else {
                            break;
                        }
                    }
                    dis.close();
                    dos.close();
                    socket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }).start();
        }
    }
}

客户端代码：

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.Socket;
import java.nio.charset.StandardCharsets;

public class SM4Client {

    private static final String HOST = "127.0.0.1";
    private static final int PORT = 8888;

    public static void main(String[] args) throws IOException {
        Socket socket = new Socket(HOST, PORT);
        System.out.println("Connected to server: " + socket.getInetAddress().getHostAddress());
        DataInputStream dis = new DataInputStream(socket.getInputStream());
        DataOutputStream dos = new DataOutputStream(socket.getOutputStream());

        String input = "这是一段测试字符串。";
        byte[] inputData = input.getBytes(StandardCharsets.UTF_8);

        // 加密
        dos.writeInt(0);  // 指定为加密操作
        dos.writeInt(inputData.length);
        dos.write(inputData);
        dos.flush();

        int encryptedLength = dis.readInt();
        byte[] encryptedData = new byte[encryptedLength];
        dis.readFully(encryptedData);
        String encryptedText = new String(encryptedData, StandardCharsets.UTF_8);
        System.out.println("Encrypted text: " + encryptedText);

        // 解密
        dos.writeInt(1);  // 指定为解密操作
        dos.writeInt(encryptedLength);
        dos.write(encryptedData);
        dos.flush();

        int decryptedLength = dis.readInt();
        byte[] decryptedData = new byte[decryptedLength];
        dis.readFully(decryptedData);
        String decryptedText = new String(decryptedData, StandardCharsets.UTF_8);
        System.out.println("Decrypted text: " + decryptedText);

        dis.close();
        dos.close();
        socket.close();
    }
}

需要注意的是，在这里我们使用了SM4算法的ECB模式进行加解密，因此需要保证每次加密的明文长度和密钥长度是一致的。在实际应用中，可以考虑使用SM4算法的CBC或CTR模式，以提高加密的安全性。同时，在实际应用中还需要考虑对数据进行完整性校验，防止数据被篡改。