How to pair between central/peripheral in lesc mode?

[faithself]

Thanks in advanced. Both platforms are: nrf52832, sdk17.0.2. The peripheral is based on ble_app_gls and I set static passkey 123456, the central is based on ble_app_hrs_c, so both sides have peer manager mechanism, I set sec_param.lesc=1 on both sides. I've implemented nus on both sides, I can use cell phone to pair/bond with the peripheral. But with nrf52832 central, I get below traces:

0> <info> app_timer: RTC: initialized.
 0> <info> app: Heart Rate collector example started.
 0> <info> app: Starting scan.
 0> <info> app: Connecting to target F92A1B6369F4
 0> <info> app: Connected.
 0> <info> app: GATT ATT MTU on connection 0x0 changed to 247.
 0> <info> app: Data length for connection 0x0 updated to 251.
 0> <info> app: BLE_GAP_EVT_LESC_DHKEY_REQUEST
 0> <info> nrf_ble_lesc: Calling sd_ble_gap_lesc_dhkey_reply on conn_handle: 0
 0> <info> app: Discovery complete.
 0> <info> app: Connected to device with Nordic UART Service.
 0> <info> peer_manager_handler: Connection secured: role: Central, conn_handle: 0, procedure: Bonding
 0> <info> app: BLE_GAP_EVT_AUTH_STATUS: status=0x0 bond=0x1 lv4: 0 kdist_own:0x3 kdist_peer:0x2
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Bonding data, action: Update
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Peer rank, action: Update
 0> <info> app: Disconnected.
 0> <info> app: Starting scan.
 0> <info> app: Disconnected, reason 0x13.
 0> <info> app: Starting scan.
 0> <info> app: Connecting to target F92A1B6369F4
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Peer rank, action: Update, no change
 0> <info> app: Connected.
 0> <info> app: GATT ATT MTU on connection 0x0 changed to 247.
 0> <info> peer_manager_handler: Connection security failed: role: Central, conn_handle: 0x0, procedure: Encryption, error: 4352
 0> <info> app: Disconnected.
 0> <info> app: Starting scan.
 0> <info> app: Disconnected, reason 0x13.
 0> <info> app: Starting scan.
 0> <info> app: Connecting to target F92A1B6369F4
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Peer rank, action: Update, no change
 0> <info> app: Connected.
 0> <info> app: GATT ATT MTU on connection 0x0 changed to 247.
 0> <info> peer_manager_handler: Connection security failed: role: Central, conn_handle: 0x0, procedure: Encryption, error: 4352
 0> <info> app: Disconnected.
 0> <info> app: Starting scan.
 0> <info> app: Disconnected, reason 0x13.

 

I don't know how to input passkey in central, the central only has display capability by RTT Viewer. Would anyone tell me how to input passkey and get authority passed?

[faithself]

Add prints of peripheral when pairing/bonding:

0> <info> app_timer: RTC: initialized.
 0> <info> app: 6-axis sensor started.
 0> <info> app: Fast advertising
 0> <info> app: TWI device detected at address 0x69
 0> <info> app: MPU6050 init success.
 0> <info> app: MPU6050 reg MPU_REG_WHO_AM_I value: 0x68.
 0> <info> app: Health Thermometer Service is scanned out.
 0> <info> app: Tx power level service is scanned out.
 0> <info> app: Custom service is scanned out.
 0> <info> app: Connected
 0> <info> app: BLE_GAP_EVT_LESC_DHKEY_REQUEST
 0> <info> nrf_ble_lesc: Calling sd_ble_gap_lesc_dhkey_reply on conn_handle: 0
 0> <info> peer_manager_handler: Connection secured: role: Peripheral, conn_handle: 0, procedure: Bonding
 0> <info> app: Collector did not use MITM, disconnecting
 0> <info> app: BLE_GAP_EVT_AUTH_STATUS: status=0x0 bond=0x1 lv4: 0 kdist_own:0x3 kdist_peer:0x2
 0> <info> app: Pair success!
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Bonding data, action: Update
 0> <info> peer_manager_handler: Peer data updated in flash: peer_id: 0, data_id: Peer rank, action: Update
 0> <info> app: Fast advertising
 0> <info> app: Tx power level service disconnected.
 0> <info> app: Custom service disconnected.
 0> <info> app: Disconnected
 0> <error> peer_manager_handler: Peer deleted successfully: peer_id: 0
 0> <info> app: Health Thermometer Service is scanned out.
 0> <info> app: Tx power level service is scanned out.
 0> <info> app: Custom service is scanned out.
 0> <info> app: Connected
 0> <info> peer_manager_handler: Connection security failed: role: Peripheral, conn_handle: 0x0, procedure: Encryption, error: 4102
 0> <warning> peer_manager_handler: Disconnecting conn_handle 0.
 0> <info> app: Fast advertising
 0> <info> app: Disconnected
 ......

[Edvin]

faithself said:

About my custom central, I see this event:

  0> <info> nrf_ble_lesc: Calling sd_ble_gap_lesc_dhkey_reply on conn_handle: 0

 dhkey implies that this is a Diffie Hellman key, which is not what you are trying to implement. The DHKey is used in LESC, while your 6-digit passkey is something else. 

I believe what you are looking for is the event BLE_GAP_EVT_AUTH_KEY_REQUEST, where you are expected to reply with sd_ble_gap_auth_key_reply(), which takes the conn_handle, the key type (@ref BLE_GAP_AUTH_KEY_TYPES, where BLE_GAP_AUTH_KEY_TYPE_PASSKEY is the parameter for passkey), and *p_key, which is a pointer to where this key is stored in ascii, much like you did in the peripheral when you store the static key.

I agree that the log says DHKEY_REQUEST, but are you sure this is the event that is also generated when you connect with your other peripherals using the static passkey?

Best regards,

Edvin