Bluetooth pairing in "client" mode

[deepakt]

Experts!

In my project, I'm using BT SPP to communicate between ESP32 and an Android device. I'm using the Arduino IDE and currently works fine. When the ESP32 comes up, I connect the Android device to the already paired ESP32 over BT. I use a Bluetooth Serial Terminal app on the Android. Data is sent and received on both devices - no issues.
Code that we're using effectively is this:

Code: Select all

#include "BluetoothSerial.h"

#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
#endif

BluetoothSerial SerialBT;

void setup() {
  Serial.begin(115200);
  SerialBT.begin("ESP32test"); //Bluetooth device name
  Serial.println("The device started, now you can pair it with bluetooth!");
}

void loop() {
  if (Serial.available()) {
    SerialBT.write(Serial.read());
  }
  if (SerialBT.available()) {
    Serial.write(SerialBT.read());
  }
  delay(20);
}

The problem I see is this: Any other device could just pair and connect to the ESP32 and send/receive data. In my project, security is needed and this issue leaves my design exposed.

What I'm looking for is:
1. How could I possibly setup the ESP32 as "client" and Android as "server". Once paired, the Android device will be in hidden/invisible/non-discoverable mode to new devices. Only the paired ESP32 "client" will be able to connect to the ANdroid device when it restarts.
2. Any "PIN" that I could set up on the ESP32 to provide some level of security?
3. Any other means by which I could make the design "intrusion" proof?

We've built quite a good system with our project using ESP32 and it has been performing very well, but this last bit is troubling us. Any help would be truly appreciated.

Regards,
Deepak

[deepakt]

Going through the file arduino-esp32/tools/sdk/include/bt/esp_spp_api.h, I came across this piece of code. Would this help me achieve what I am looking for?

Code: Select all

typedef enum {
    ESP_SPP_ROLE_MASTER     = 0,          /*!< Role: master */
    ESP_SPP_ROLE_SLAVE      = 1,          /*!< Role: slave */
} esp_spp_role_t;

[deepakt]

Hi,

Anyone out there who could help?

[vinots]

Hi,

sorry I'm not an expert.

As told viewtopic.php?t=5537 at the end, can use pairing. Maybe encrypt packets for ethereal?

good luck!

toni

[deepakt]

Thankyou Toni for replying.

The link you referred to was for BLE, while we're using BT Classic. Moving to BLE would take a lot of effort for us at this stage.

I'm not even sure if BT Classic on Arduino supports master/socket server configuration currently. The library does not have any examples for a master/server configuration, and hence call for help here. Hopefully I can get some information on this soon.

Thanks again.

Regards,
Deepak

[bilalchaudry9]

Hi,
Did you find any solution to this?

Regards,
Bilal Chaudry,