main.java

import java.util.*;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
import java.nio.ByteOrder;
import java.nio.ByteBuffer;

public class Main {
  static class Barista {
    public byte[] encryptedMachinePassword = "0000000000000000".getBytes();
    public byte[] encryptedToken = "0000000000000000".getBytes();
    public byte[] encryptionKey = "0000000000000000".getBytes();

    private byte[] encdec(byte[] data, int param) {
      Cipher instance = Cipher.getInstance(data.length == 16 ? "AES/ECB/NOPADDING" : "AES/ECB/PKCS5Padding");
      instance.init(param, new SecretKeySpec(this.encryptionKey, "AES"));
      return instance.doFinal(data);
    }

    public byte[] decrypt(byte[] data) {
      return encdec(data, 2);
    }

    public byte[] encrypt(byte[] data) {
      return encdec(data, 1);
    }

    public byte[] getHibun() {
      byte[] machinePassword = decrypt(this.encryptedMachinePassword);
      byte[] decryptedToken = decrypt(this.encryptedToken);
      byte[] haisyo = new byte[16];
      for (int i = 0; i < 16; i++) {
          haisyo[i] = (byte) ((machinePassword[i] ^ decryptedToken[i]) & 0xFF);
      }
      return haisyo;
    }

    public byte[] str2hex(String str) {
      return DatatypeConverter.parseHexBinary(str.replaceAll(" ",""));
    }

    public String hex2str(byte[] data) {
      return DatatypeConverter.printHexBinary(data);
    }

    public byte[] getTime() {
      byte[] rand = new byte[4];
      new Random().nextBytes(rand);

      int time = (int)(new Date().getTime() / 1000);
      byte[] data = ByteBuffer.allocate(4).order(ByteOrder.BIG_ENDIAN).putInt(time).array();
      return (encrypt(new byte[]{data[0], data[1], data[2], data[3], rand[0], rand[1], rand[2], rand[3]}));
    }

    public byte[] getButtonCmd(int button) {
      byte[] rand = new byte[4];
      new Random().nextBytes(rand);
      return encrypt(new byte[]{(byte)((button >> 8) & 0xFF), (byte)(button & 0xFF), rand[0], rand[1], rand[2], rand[3]});
    }
  }

  public static void main(String[] args) throws Exception {
    Scanner scan = new Scanner(System.in);
    Barista barista = new Barista();

    // lightpairing
    System.out.println("char-read-hnd 0x0028");
    System.out.println("char-read-hnd 0x0030");
    System.out.print("Return Value> ");
    barista.encryptedToken = barista.str2hex(scan.nextLine());
    System.out.println("char-write-req 0x0030 " + barista.hex2str(barista.encrypt(barista.getHibun())));

    System.out.println("char-write-req 0x0030 " + barista.hex2str("WE START PAIRING".getBytes("US-ASCII")));
    System.out.println("char-read-hnd 0x0030");
    System.out.println("touch LED");
    System.out.print("Return Value> ");
    barista.encryptedMachinePassword = barista.str2hex(scan.nextLine());

    System.out.println("char-read-hnd 0x0030");
    System.out.print("Return Value> ");
    barista.encryptionKey = barista.str2hex(scan.nextLine());
    System.out.println("char-write-req 0x0030 " + barista.hex2str(barista.encrypt(barista.getHibun())));

    // payload
    while (true) {
      System.out.println("---");
      int[] buttons = {1, 2, 4, 8, 16, 32, 64, 256};
      for (int button: buttons) {
        byte[] payload = barista.getButtonCmd(button);
        System.out.println("button " + button + ": char-write-req 0x002e " + barista.hex2str(payload));
      }

      System.out.print("re-Generate?");
      scan.nextLine();
    }
  }
}