Hi,
Have a ble server on esp32 with arduino. When connecting with nrfconnect, I get a pop up window to enter a passkey for pairing/authentication. How can I get this pop up to show in my mit app inventor app?
I use the Bluetooth le extension.
Thank you
Regards
Ludo
You simply make your own Ludo. Pop-up a Notification Block that the User has to enter a pass key to. The Arduino doesn't need to know about it, just the App.
Hi John,
Thanks for your quick feedback.
But it needs to take the arduino passkey request to reply to... Isn't it?
I understood from chatgpt that android stack is normally taking care of that, but since it works with nrfconnect, and not with mit app, I would assume something should be done in mit app... But what? Any help is welcome
Regards
Ludo
Well, how would the Arduino retain a passkey? You could implement a key in the Sketch, but that would then require a connection first. Better then to use my suggestion - have the pass key in the App. If the User fails to enter the correct key, the App can be closed.
Chris,
I really need to implement a secure link according ble secure specification.
I have on my server a passkey, that immediately changes after first use, and that is transmitted in an encrypted way, so I am trying to find a solution.
Regards
Ludo
does anyone know how to initiate a bonding with the arduino app, it looks as ESP_GAP_BLE_PASSKEY_REQ_EVT: in GAPeventhandler must be triggered to start the bonding. With nrfconnect, it works, with MIT app , I am not sure how to initiate. Does anyone know where to find specifications on bluetoothLE extension, so I can check if it may be in there ?
BLE is secure by design, without pass keys.
Where did you find: "ESP_GAP_BLE_PASSKEY_REQ_EVT" - that looks like it is from a script?
There is a BLE Security study guide:
... and here is someone trying to do what you want to do:
Chris,
Thank you for your reply.
You mentioned : BLE is secure by design, without pass keys....yes, but first you must authenticate with a passkey, which is done when using nrfConnect, but cannot find how to do this with the MIT app.
Thank you for the attached guides, but I am looking for the manual/guide on the BluetoothLE extension , used in mit app inventor, to see if there is a way to initiate pairing/bonding.
ESP_GAP_BLE_PASSKEY_REQ_EVT is in the esp_gap_ble_api.h from espressif for the Arduino. Gapeventhandler is used in Arduino ESP32 program.
I have passed your Topic to the developer of the MIT BLE extension, Evan.
I think that is only because your Sketch/Script includes that method of authentication?
Hi Chris,
You can delete this request, I finally got it to work by arduino code. I am still trying to figure out which lines did it, as I just added several lines of param settings at once, and just tried... It then asked if I accepted paring and could give in the passkey by android popup...
Amazing that a pop up can make you happy 
. Thank you for helping out.
Note : I still do not understand why android pops up when using nrfconnect with less arduino parameters set up, and needs more parameters with mit app... I still assume they invoke it.... So, if mit people would find out why, I am still interested to understand...
Regards
Ludo
We would love to see what worked for you.
Could you post the working code and blocks?
1 Like
// Security parameters :
I had following 2 lines :
////esp_ble_auth_req_t auth_req = ESP_LE_AUTH_REQ_SC_MITM_BOND; // Secure Connections, MITM, Bonding
////esp_ble_io_cap_t iocap = ESP_IO_CAP_KBDISP; // Passkey entry (display on device)
and changed to :
esp_ble_auth_req_t auth_req = ESP_LE_AUTH_REQ_SC_MITM_BOND;
esp_ble_io_cap_t iocap = ESP_IO_CAP_OUT;
uint8_t key_size = 16;
uint8_t init_key = ESP_BLE_ENC_KEY_MASK | ESP_BLE_ID_KEY_MASK;
uint8_t rsp_key = ESP_BLE_ENC_KEY_MASK | ESP_BLE_ID_KEY_MASK;
uint32_t passkey = fixedPasskey;
uint8_t auth_option = ESP_BLE_ONLY_ACCEPT_SPECIFIED_AUTH_DISABLE;
and in setup, from the //// lines to the next :
////esp_ble_gap_set_security_param(ESP_BLE_SM_AUTHEN_REQ_MODE, &auth_req, sizeof(auth_req)); // SC + MITM + BOND
////esp_ble_gap_set_security_param(ESP_BLE_SM_IOCAP_MODE, &iocap, sizeof(iocap)); // IO capabilities
////esp_ble_gap_set_security_param(ESP_BLE_SM_SET_STATIC_PASSKEY, &fixedPasskey, sizeof(fixedPasskey)); // Fixed passkey
esp_ble_gap_set_security_param(ESP_BLE_SM_SET_STATIC_PASSKEY, &passkey, sizeof(uint32_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_AUTHEN_REQ_MODE, &auth_req, sizeof(uint8_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_IOCAP_MODE, &iocap, sizeof(uint8_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_MAX_KEY_SIZE, &key_size, sizeof(uint8_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_ONLY_ACCEPT_SPECIFIED_SEC_AUTH, &auth_option, sizeof(uint8_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_SET_INIT_KEY, &init_key, sizeof(uint8_t));
esp_ble_gap_set_security_param(ESP_BLE_SM_SET_RSP_KEY, &rsp_key, sizeof(uint8_t));
I assume, but could not check further in detail that SET_INIT_KEY and SET_RSP_KEY were missing from my previous settings. ...and it is not the MIT app code/blocks that excecute, but it is android stack that takes care of the authentication procedure.