Is there an API that can get the authentication method?

[sdi_kei]

Hello.
I am developing using nrf52832 (S132 v7.0.1, SDK v17.0.0) as a peripheral device.

I want to know the authentication method of the central device when the connection is established.
Is there an API that can get the authentication method?

Also, when BLE_GAP_EVT_CONNECTED of ble_evt_handler is called, you can see the security parameters by checking "p_ble_evt-> evt-> gap_evt-> params-> sec_params_request-> peer_params".
Is it possible to know the authentication method of the central device by comparing it with the value on the following site and checking the authentication method?

Best regards.

[Sigurd]

Hi,

You can get the getting the security status of a connection using pm_conn_sec_status_get()

You also have the BLE_GAP_EVT_AUTH_STATUS event (Authentication procedure completed event)

         case BLE_GAP_EVT_AUTH_STATUS:
             NRF_LOG_INFO("BLE_GAP_EVT_AUTH_STATUS: status=0x%x bond=0x%x lv4: %d kdist_own:0x%x kdist_peer:0x%x",
                          p_ble_evt->evt.gap_evt.params.auth_status.auth_status,
                          p_ble_evt->evt.gap_evt.params.auth_status.bonded,
                          p_ble_evt->evt.gap_evt.params.auth_status.sm1_levels.lv4,
                          *((uint8_t *)&p_ble_evt->evt.gap_evt.params.auth_status.kdist_own),
                          *((uint8_t *)&p_ble_evt->evt.gap_evt.params.auth_status.kdist_peer));

[sdi_kei]

Hello.

thank you for your answer.
I know I can get the status of the connection, but looking at that information doesn't tell me which authentication method to use.
The authentication methods I would like to know are "Numeric Comparison" and "Passkey Entry".
Is it possible to obtain information like the site below?

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fsdk_nrf5_v17.0.0%2Flib_pm_usage.html

Best regards.

[Sigurd]

Hi,

I could not find a API for that. But in BLE_GAP_EVT_SEC_PARAMS_REQUEST you get the I/O capabilities of the other device.

Depending on the method used, you will get different events. See these Message Sequence Charts:

Bonding: Numeric Comparison:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s112.api.v7.3.0/group___b_l_e___g_a_p___p_e_r_i_p_h___l_e_s_c___b_o_n_d_i_n_g___n_c___m_s_c.html

Bonding: Passkey Entry, User Inputs on Peripheral:

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s112.api.v7.3.0/group___b_l_e___g_a_p___p_e_r_i_p_h___l_e_s_c___b_o_n_d_i_n_g___p_k_e___c_d___m_s_c.html

[sdi_kei]

Hello.

BLE_GAP_EVT_SEC_PARAMS_REQUEST, but this event occurs late. This is because it is confirmed that pairing will be performed when this event occurs. I want to know how to authenticate to determine if it's a pairing device.

Is there any good way?

Best regards.

[Sigurd]

sdi_kei said:

BLE_GAP_EVT_SEC_PARAMS_REQUEST, but this event occurs late. This is because it is confirmed that pairing will be performed when this event occurs

No, you can use sd_ble_gap_sec_params_reply() to reply with a error-code and the paring will fail.

If you look at the IO capabilities(BLE_GAP_EVT_SEC_PARAMS_REQUEST, ble_gap_sec_params_t ble_gap_sec_params_t::io_caps and ::lesc), you should be able to determine the authentication method. See the table at step 4 here: https://www.bluetooth.com/blog/bluetooth-pairing-part-2-key-generation-methods/