public class Element {
   public int id; // 4 byte
   
   public Element(int id) {
      this.id = id;
   }
}
// This would be a total of 12 bytes from my understanding (8 for header, 4 for int id)

// and then have another class
public class Unit {
   public int uid; // 4 byte
   public Element element; // ?? byte
}

package server.encryption;

import java.io.*;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.*;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public class KeyReader {

   public static PrivateKey getPrivateKey(InputStream in) throws Exception {
//      System.err.println(filename);
//      File f = new File(filename);
      //DataInputStream dis = new DataInputStream(is);
      ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(in));
      BigInteger m = (BigInteger) oin.readObject();
      BigInteger e = (BigInteger) oin.readObject();
      RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(m, e);
       KeyFactory fact = KeyFactory.getInstance("RSA");
       PrivateKey privateKey = fact.generatePrivate(keySpec);
       oin.close();
       return privateKey;
//      PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
//      KeyFactory kf = KeyFactory.getInstance("RSA");
//      return kf.generatePrivate(spec);
   }
   
   public static byte[] rsaDecrypt(byte[] data) throws Exception {
      System.err.println(KeyReader.class.getResourceAsStream("privatekey.der").toString());
      PrivateKey privateKey = getPrivateKey(KeyReader.class.getResourceAsStream("privatekey.der"));
      Cipher cipher = Cipher.getInstance("RSA");
      cipher.init(Cipher.DECRYPT_MODE, privateKey);
      byte[] cipherData = cipher.doFinal(data);
      return cipherData;
   }
   
   public static byte[] aesDecrypt(byte[]data, byte[]key) throws Exception {
      SecretKeySpec secretKeySpec = new SecretKeySpec(key, "AES");
      Cipher cipher = Cipher.getInstance("AES");
      cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, cipher.getParameters());
      byte[] cipherData = cipher.doFinal(data);
      return cipherData;
   }
   
}

      try {
         this.serverSocket = new ServerSocket(this.port);
         this.listening = true;
            while (listening) {
                Socket socket = this.serverSocket.accept();
                socket.setTcpNoDelay(true);
                DebugConsole.print("Client connection from " + socket.getRemoteSocketAddress(), "General");
                PacketAction socketConnection = new PacketAction(socket, this);
                socketConnection.start();
                this.clientConnections.add(socketConnection);
            };
        }
        catch (Exception e) {
            DebugConsole.print("Exception (run): " + e.getMessage(), "Error");
        }