bos3_client

package com.example.bos3;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.EditText;
import android.widget.TextView;

import android.view.View;
import android.widget.Button;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.InputStream;
import java.io.PrintWriter;
import java.net.Socket;
import java.nio.*;
import java.nio.charset.Charset;
import java.security.*;
import java.security.spec.*;
import javax.crypto.spec.*;
import javax.crypto.*;

import android.util.Base64;

public class MainActivity extends AppCompatActivity {

    Thread Thread1 = null;
    EditText serverIP, serverPort;
    EditText userMessage;
    TextView chatMessages;
    Button btnSend;
    Thread ThreadConnect = null;

    String SERVER_IP;
    int SERVER_PORT;

    InputStream in_stream;
    OutputStream soc_out_stream;
    Cipher cipher;
    Cipher cipher_d;
    Cipher cipher_rsa;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        serverIP = findViewById(R.id.editIp);
        serverPort = findViewById(R.id.editPort);

        // Значения по умолчанию
        serverIP.setText("10.0.2.2"); // Вместо 127.0.0.1 используем этот адрес
        serverPort.setText("9001");


        chatMessages = findViewById(R.id.chatId);
        userMessage = findViewById(R.id.userMsg);
        btnSend = findViewById(R.id.btnSend);

        Button btnConnect = findViewById(R.id.btnConnect);
        btnConnect.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                chatMessages.setText("");
                SERVER_IP = serverIP.getText().toString().trim();
                SERVER_PORT = Integer.parseInt(serverPort.getText().toString().trim());
                Thread ThreadConnect = new Thread(new ThreadConnect());
                ThreadConnect.start();
            }
        });

        Button btnSend = findViewById(R.id.btnSend);
        btnSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String userMsg = userMessage.getText().toString().trim();
                if (!userMsg.isEmpty()) {
                    new Thread(new ThreadSendMsg(userMsg)).start();
                }
            }
        });
    }


    private PrintWriter output;
    private BufferedReader input;

    class ThreadConnect implements Runnable {
        @Override
        public void run() {
            Socket socket;
            try {
                socket = new Socket(SERVER_IP, SERVER_PORT);
                soc_out_stream = socket.getOutputStream();
                output = new PrintWriter(soc_out_stream);
                input = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                in_stream = socket.getInputStream();

                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        chatMessages.setText("Connected to server\n");
                    }
                });
                new Thread(new ChatThread()).start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    class ChatThread implements Runnable {
        @Override
        public void run() {
            //Handshake
            String keyBytes = "";
            try {
                String line = input.readLine();
                while (!line.equals("-----END PUBLIC KEY-----")) {
                    keyBytes += line + "\n";
                    line = input.readLine();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }


            String pubKeyPEM = keyBytes.replace("-----BEGIN PUBLIC KEY-----\n", "");
            pubKeyPEM = pubKeyPEM.replace("-----END PUBLIC KEY-----", "");
            byte[] encoded = Base64.decode(pubKeyPEM, android.util.Base64.DEFAULT);
            X509EncodedKeySpec spec =
                    new X509EncodedKeySpec(encoded);
            final PublicKey pub_key;
            try {
                cipher_rsa = Cipher.getInstance("RSA/ECB/OAEPWithSHA-1AndMGF1Padding");
            } catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
                e.printStackTrace();
            }
            try {
                KeyFactory kf = KeyFactory.getInstance("RSA");
                pub_key = kf.generatePublic(spec);

                cipher_rsa.init(Cipher.ENCRYPT_MODE, pub_key);
            } catch (NoSuchAlgorithmException | InvalidKeySpecException | InvalidKeyException e) {
                System.err.println("");
            }


            byte[] iv = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
            IvParameterSpec ivspec = new IvParameterSpec(iv);

            try {
                SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");

                SecureRandom r = new SecureRandom();
                byte[] aesKey = new byte[16];
                r.nextBytes(aesKey);

                try {
                    cipher_rsa.update(aesKey);
                    try {
                        byte[] cipherText = cipher_rsa.doFinal();
                        soc_out_stream.write(cipherText);
                        soc_out_stream.flush();
                    } catch (BadPaddingException | IllegalBlockSizeException e) {
                        e.printStackTrace();
                    }

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

                SecretKey tmp = new SecretKeySpec(aesKey, "AES");
                cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
                cipher_d = Cipher.getInstance("AES/ECB/PKCS5Padding");
                cipher.init(Cipher.ENCRYPT_MODE, tmp);
                cipher_d.init(Cipher.DECRYPT_MODE, tmp);

                AlgorithmParameters params = cipher.getParameters();

            } catch (NoSuchAlgorithmException | NoSuchPaddingException
                    | InvalidKeyException e) {
                e.printStackTrace();
            }

            while (true) {
                try {
                    final byte[] message = new byte[4096];
                    final int recv = in_stream.read(message);
                    if (message != null) {
//                        cipher_d.update(Base64.decode(message, android.util.Base64.DEFAULT));
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                try {
                                    byte[] cyph = new byte[recv];
                                    System.arraycopy(message, 0, cyph, 0, recv);
                                    byte[] plain = cipher_d.doFinal(cyph);
                                    String msg = new String(plain, Charset.forName("UTF-8"));
                                    chatMessages.append("Server: " + msg + "\n");
                                } catch (BadPaddingException | IllegalBlockSizeException e) {
                                    e.printStackTrace();
                                }
                            }
                        });
                    } else {
                        ThreadConnect = new Thread(new ThreadConnect());
                        ThreadConnect.start();
                        return;
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    class ThreadSendMsg implements Runnable {
        private String message;

        ThreadSendMsg(String message) {
            this.message = message;
        }

        @Override
        public void run() {
            byte[] b = message.getBytes();
            cipher.update(b);
            try {
                byte[] cipher_text = cipher.doFinal();
                soc_out_stream.write(cipher_text);
                soc_out_stream.flush();
            } catch (BadPaddingException | IllegalBlockSizeException | IOException e) {
                e.printStackTrace();
            }
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    chatMessages.append("Сlient: " + message + "\n");
                    userMessage.setText("");
                }
            });
        }
    }
}