Windows 8.1 bonding/pairing error

[Valer_I]

Hello all, before I decided to write my own question I read the forum thoroughly. How ever no aid found to solve my problem. At first I want to make "just work" bonding(pairing) to encrypt further communication. I saw many nordic examples for this using DeviceManager+pstorage. However my RAM budget could not allow usage of this lib. I try to do this manually without saving keys in flash( at present revision). When initiate pairing from windows 8.1 the flow are next (in debug):

BLE_GAP_EVT_CONNECTED
BLE_GAP_ROLE_PERIPH (ID 3)
BLE_GAP_EVT_SEC_PARAMS_REQUEST
   Sec params from host: 
   Bond: 1
   Io_caps: 4
   kdist_central: 124
   kdist_periph: 219
   max_key_size: 16
   min_key_size: 0
   mitm: 1
   oob: 0

My peripheral answers:

 uint32_t res=sd_ble_gap_sec_params_reply(ble_evt->evt.gap_evt.conn_handle,BLE_GAP_SEC_STATUS_SUCCESS,&m_sec_params,NULL);

where m_sec_params are:

        #define SEC_PARAM_BOND                       1
        #define SEC_PARAM_MITM                        0 
        #define SEC_PARAM_IO_CAPABILITIES       BLE_GAP_IO_CAPS_NONE 
        #define SEC_PARAM_OOB                         0
        #define SEC_PARAM_MIN_KEY_SIZE           7 
        #define SEC_PARAM_MAX_KEY_SIZE          16  

 



 BLE_GAP_EVT_AUTH_STATUS
      Auth status: 0x88 , Src: Remote  
      //BLE_GAP_SEC_STATUS_UNSPECIFIED            0x88  /**< Unspecified reason. */
    Disconnect from host, reason 19 
      //BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION           0x13  
      /**< Remote User Terminated Connection. */

When initiate pairing from Android the flow are next:

BLE_GAP_EVT_CONNECTED
BLE_GAP_ROLE_PERIPH (ID: 3)
BLE_GAP_EVT_SEC_PARAMS_REQUEST
Sec params from host: 
  Bond: 1
  Io_caps: 4
  kdist_central: 231
  kdist_periph: 119
  max_key_size: 16
  min_key_size: 0
  mitm: 1
  oob: 0
BLE_GAP_EVT_CONN_SEC_UPDATE
BLE_GAP_EVT_AUTH_STATUS
Auth status: 00, Src: Local 

//Success.

Than I have a look on examples: and found that windows 8.1 paired correctly when at BLE_GAP_EVT_SEC_PARAMS_REQUEST peripheral answers:

uint32_t res=sd_ble_gap_sec_params_reply(ble_evt->evt.gap_evt.conn_handle,BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP,NULL,NULL);

Then central (windows) disconnects and reconnects. Now it is possible to work with device. The problem is that Android do not support such trick. i.e. BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP and show the pairing failure. Please help to make device bondable/pairable on both win and android devices. Or may be it would beter to show key pieces of code from DM where it made properly.

best regards.

[Valer_I]

The solution found!

in static void sec_params_init(void)

I've just add:

m_sec_params.kdist_periph.enc   = 1;
m_sec_params.kdist_periph.id    = 1;
m_sec_params.kdist_periph.sign  = 0;

And now it works.

[Hung Bui]

@Valer_I: It's great that you found. I actually forgot that, if we don't set the m_sec_params.kdist_periph.enc = 1; we will not distribute LTK and will not do bonding. I think Windows won't accept pairing without bonding. And this explained the issue you encounted.

m_sec_params.kdist_periph.id = 1; is not needed since we don't use resolvable random address.

[Matt]

@Hung Bui: In SDK6.1 and SD7.0.0, have this issue, but the SD have not the "kdist_periph" struct of m_sec_params!!

[Hung Bui]

@Matt: It's not configurable with the previous SDKs, but have you made sure you have set .sec_param.bond = 1 when call sd_ble_gap_sec_params_reply() ? This will force the peripheral to send LTK. Have you tried to test with the ble_app_proximity for example ?

[Matt]

@Hung Bui: sec_param.bond = 1, I have test ble_app_proximity and nRF Toolbox in iOS9.1(Apple just release), have this issue. I have asked the question: link text