Automatically connected without putting the static passkey at the time of pairing with out bonding.

[prayuktibid]

Hello, 

I am trying connect with the nRF52840 dongle from my android phone using nRF Connect App. The nRF52840 dongle as peripheral and I am using nRF SDK 15.20 and s140_nRF52_6.1.1 device.  My objective is The nRF52840 dongle should connect with nRF Connect App after getting the passkey reply from nRF Connect App otherwise it should not connect.

I am using static passkey at the time of pairing not bonding. I have taken reference from This document.  and I have implemented in ble_app_gls example. But I disn't get what actually I am wanting. After getting the BLE device by scanning whenever I pressed the "connect" in APP it is connected with the nRF Dongle without putting the passkey also the pairing pop-ups is coming but when I click on "pair" on the paring pop-up dongle disconnected. But the dongle should connect with the nRF APP after putting the passkey on the app. This is my full code below

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/** @file
 *
 * @defgroup ble_sdk_app_gls_main main.c
 * @{
 * @ingroup ble_sdk_app_gls
 * @brief Glucose Meter service Sample Application
 *
 * This file contains the source code for a sample application using the Glucose Meter service
 * (and also Battery and Device Information services). This application uses the
 * @ref srvlib_conn_params module.
 */

#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "app_error.h"
#include "ble.h"
#include "ble_err.h"
#include "ble_hci.h"
#include "ble_srv_common.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_dis.h"
#include "ble_bas.h"
#include "ble_gls.h"
#include "ble_racp.h"
#include "ble_conn_params.h"
#include "sensorsim.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "app_timer.h"
#include "peer_manager.h"
#include "peer_manager_handler.h"
#include "bsp_btn_ble.h"
#include "fds.h"
#include "ble_conn_state.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_lesc.h"
#include "nrf_ble_qwr.h"
#include "nrf_pwr_mgmt.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

// UART STUFFS


#define DEVICE_NAME                     "BLE_Trigger"                               /**< Name of device. Will be included in the advertising data. */
#define MANUFACTURER_NAME               "xyz"                               /**< Manufacturer. Will be passed to Device Information Service. */
#define MODEL_NUMBER                    "nRF52840"                                  /**< Model Number string. Will be passed to Device Information Service. */
#define MANUFACTURER_ID                 0x55AA55AA55                                /**< DUMMY Manufacturer ID. Will be passed to Device Information Service. You shall use the ID for your Company*/
#define ORG_UNIQUE_ID                   0xEEBBEE                                    /**< DUMMY Organisation Unique ID. Will be passed to Device Information Service. You shall use the Organisation Unique ID relevant for your Company */

#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */
#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define APP_ADV_INTERVAL                40                                          /**< The advertising interval (in units of 0.625 ms. This value corresponds to 25 ms). */
#define APP_ADV_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define BATTERY_LEVEL_MEAS_INTERVAL     APP_TIMER_TICKS(10000)                      /**< Battery level measurement interval (ticks). */
#define MIN_BATTERY_LEVEL               81                                          /**< Minimum battery level as returned by the simulated measurement function. */
#define MAX_BATTERY_LEVEL               100                                         /**< Maximum battery level as returned by the simulated measurement function. */
#define BATTERY_LEVEL_INCREMENT         1                                           /**< Value by which the battery level is incremented/decremented for each call to the simulated measurement function. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(10, UNIT_1_25_MS)             /**< Minimum acceptable connection interval (10 ms). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)            /**< Maximum acceptable connection interval (100 ms) */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds). */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAM_UPDATE_COUNT     3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define LESC_DEBUG_MODE                 0                                           /**< Set to 1 to use LESC debug keys, allows you to use a sniffer to inspect traffic. */

#define SEC_PARAM_BOND                  0                                           /**< Perform bonding. */
#define SEC_PARAM_MITM                  1                                           /**< Man In The Middle protection required (applicable when display module is detected). */
#define SEC_PARAM_LESC                  0                                           /**< LE Secure Connections enabled. */
#define SEC_PARAM_KEYPRESS              0                                           /**< Keypress notifications not enabled. */
#define SEC_PARAM_IO_CAPABILITIES       BLE_GAP_IO_CAPS_KEYBOARD_DISPLAY            /**< Display I/O capabilities. */
#define SEC_PARAM_OOB                   0                                           /**< Out Of Band data not available. */
#define SEC_PARAM_MIN_KEY_SIZE          7                                           /**< Minimum encryption key size. */
#define SEC_PARAM_MAX_KEY_SIZE          16                                          /**< Maximum encryption key size. */

#define PASSKEY_TXT                     "Passkey:"                                  /**< Message to be displayed together with the pass-key. */
#define PASSKEY_TXT_LENGTH              8                                           /**< Length of message to be displayed together with the pass-key. */
#define PASSKEY_LENGTH                  6                                           /**< Length of pass-key received by the stack for display. */
#define STATIC_PASSKEY                  "123455"                                    /**< paass key for pairing */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */


BLE_BAS_DEF(m_bas);                                                                 /**< Structure used to identify the battery service. */
BLE_GLS_DEF(m_gls);                                                                 /**< Structure used to identify the glucose service. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */
APP_TIMER_DEF(m_battery_timer_id);                                                  /**< Battery timer. */

static m_peer_to_be_deleted = PM_PEER_ID_INVALID;
static uint16_t     m_conn_handle = BLE_CONN_HANDLE_INVALID;                        /**< Handle of the current connection. */
static ble_uuid_t   m_adv_uuids[] =                                                 /**< Universally unique service identifiers. */
{
    {BLE_UUID_GLUCOSE_SERVICE, BLE_UUID_TYPE_BLE},
    {BLE_UUID_BATTERY_SERVICE, BLE_UUID_TYPE_BLE},
    {BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE}
};
static sensorsim_cfg_t   m_battery_sim_cfg;                                         /**< Battery Level sensor simulator configuration. */
static sensorsim_state_t m_battery_sim_state;                                       /**< Battery Level sensor simulator state. */


static void advertising_start(bool erase_bonds);



///// Added for bonding with password //////

//static  ble_opt_t passkey_opt;
//uint8_t passkey[] = STATIC_PASSKEY;
static void set_static_passkey()
{
    static ble_opt_t    m_static_pin_option;

    uint8_t passkey[] = STATIC_PASSKEY;

    m_static_pin_option.gap_opt.passkey.p_passkey = &passkey[0];

    uint32_t err_code =  sd_ble_opt_set(BLE_GAP_OPT_PASSKEY, &m_static_pin_option);

    APP_ERROR_CHECK(err_code);     

}
///// Added for bonding with password //////



/**@brief Callback function for asserts in the SoftDevice.
 *
 * @details This function will be called in case of an assert in the SoftDevice.
 *
 * @warning This handler is an example only and does not fit a final product. You need to analyze
 *          how your product is supposed to react in case of Assert.
 * @warning On assert from the SoftDevice, the system can only recover on reset.
 *
 * @param[in] line_num   Line number of the failing ASSERT call.
 * @param[in] file_name  File name of the failing ASSERT call.
 */
void assert_nrf_callback(uint16_t line_num, const uint8_t * p_file_name)
{
    app_error_handler(DEAD_BEEF, line_num, p_file_name);
}

/**@brief Function for handling Peer Manager events.
 *
 * @param[in] p_evt  Peer Manager event.
 */
static void pm_evt_handler(pm_evt_t const * p_evt)
{
    ret_code_t err_code;

    pm_handler_on_pm_evt(p_evt);
    pm_handler_disconnect_on_sec_failure(p_evt);
    pm_handler_flash_clean(p_evt);

    switch (p_evt->evt_id)
    {
        case PM_EVT_CONN_SEC_SUCCEEDED:
        {
            pm_conn_sec_status_t conn_sec_status;

            // Check if the link is authenticated (meaning at least MITM).
            err_code = pm_conn_sec_status_get(p_evt->conn_handle, &conn_sec_status);
            APP_ERROR_CHECK(err_code);

            if (conn_sec_status.mitm_protected)
            {
                NRF_LOG_INFO("Link secured. Role: %d. conn_handle: %d, Procedure: %d",
                             ble_conn_state_role(p_evt->conn_handle),
                             p_evt->conn_handle,
                             p_evt->params.conn_sec_succeeded.procedure);
            }
            else
            {
                // The peer did not use MITM, disconnect.
                NRF_LOG_INFO("Collector did not use MITM, disconnecting");
                err_code = pm_peer_id_get(m_conn_handle, &m_peer_to_be_deleted);
                APP_ERROR_CHECK(err_code);
                err_code = sd_ble_gap_disconnect(m_conn_handle,
                                                 BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
                APP_ERROR_CHECK(err_code);
            }
        } break;

        case PM_EVT_CONN_SEC_FAILED:
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            break;

        case PM_EVT_PEERS_DELETE_SUCCEEDED:
            advertising_start(false);
            break;

        default:
            break;
    }
}


/**@brief Function for handling Service errors.
 *
 * @details A pointer to this function will be passed to each service which may need to inform the
 *          application about an error.
 *
 * @param[in] nrf_error  Error code containing information about what went wrong.
 */
static void service_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}


/**@brief Function for performing battery measurement and updating the Battery Level characteristic
 *        in Battery Service.
 */
static void battery_level_update(void)
{
    ret_code_t err_code;
    uint8_t  battery_level;

    battery_level = (uint8_t)sensorsim_measure(&m_battery_sim_state, &m_battery_sim_cfg);

    err_code = ble_bas_battery_level_update(&m_bas, battery_level, BLE_CONN_HANDLE_ALL);
    if ((err_code != NRF_SUCCESS) &&
        (err_code != NRF_ERROR_INVALID_STATE) &&
        (err_code != NRF_ERROR_RESOURCES) &&
        (err_code != NRF_ERROR_BUSY) &&
        (err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)
       )
    {
        APP_ERROR_HANDLER(err_code);
    }
}


/**@brief Function for handling the Battery measurement timer timeout.
 *
 * @details This function will be called each time the battery level measurement timer expires.
 *
 * @param[in] p_context  Pointer used for passing some arbitrary information (context) from the
 *                       app_start_timer() call to the timeout handler.
 */
static void battery_level_meas_timeout_handler(void * p_context)
{
    UNUSED_PARAMETER(p_context);
    battery_level_update();
}


/**@brief Function for updating glucose measurement and updating glucose characteristic in Glucose.
          Service.
 */
static void read_glucose_measurement(void)
{
    ble_gls_rec_t rec;
    uint32_t      err_code;

    static int16_t s_mantissa = 550;
    static int16_t s_exponent = -3;
    static uint8_t s_secs     = 5;

    // simulate the reading of a glucose measurement.
    rec.meas.flags = BLE_GLS_MEAS_FLAG_TIME_OFFSET |
                     BLE_GLS_MEAS_FLAG_CONC_TYPE_LOC |
                     BLE_GLS_MEAS_FLAG_UNITS_MOL_L;
    rec.meas.base_time.year                 = 2012;
    rec.meas.base_time.month                = 1;
    rec.meas.base_time.day                  = 1;
    rec.meas.base_time.hours                = 12;
    rec.meas.base_time.minutes              = 30;
    rec.meas.base_time.seconds              = s_secs;
    rec.meas.glucose_concentration.exponent = s_exponent;
    rec.meas.glucose_concentration.mantissa = s_mantissa;
    rec.meas.time_offset                    = 0;
    rec.meas.type                           = BLE_GLS_MEAS_TYPE_CAP_BLOOD;
    rec.meas.sample_location                = BLE_GLS_MEAS_LOC_FINGER;
    rec.meas.sensor_status_annunciation     = 0;

    // change values for next read.
    s_mantissa += 23;
    if (s_mantissa > 939)
    {
        s_mantissa -= 434;
    }

    s_secs += 3;
    if (s_secs > 59)
    {
        s_secs = 0;
    }

    err_code = ble_gls_glucose_new_meas(&m_gls, &rec);
    if (err_code != NRF_SUCCESS)
    {
        // Do nothing.
    }
}


/**@brief Function for the Timer initialization.
 *
 * @details Initializes the timer module. This creates and starts application timers.
 */
static void timers_init(void)
{
    ret_code_t err_code;

    // Initialize timer module.
    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);

    // Create timers.
    err_code = app_timer_create(&m_battery_timer_id,
                                APP_TIMER_MODE_REPEATED,
                                battery_level_meas_timeout_handler);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for the GAP initialization.
 *
 * @details This function sets up all the necessary GAP (Generic Access Profile) parameters of the
 *          device including the device name, appearance, and the preferred connection parameters.
 */
static void gap_params_init(void)
{
    ret_code_t              err_code;
    ble_gap_conn_params_t   gap_conn_params;
    ble_gap_conn_sec_mode_t sec_mode;

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);

    err_code = sd_ble_gap_device_name_set(&sec_mode,
                                          (const uint8_t *)DEVICE_NAME,
                                          strlen(DEVICE_NAME));
    APP_ERROR_CHECK(err_code);

    err_code = sd_ble_gap_appearance_set(BLE_APPEARANCE_GENERIC_GLUCOSE_METER);
    APP_ERROR_CHECK(err_code);

    memset(&gap_conn_params, 0, sizeof(gap_conn_params));

    gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
    gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
    gap_conn_params.slave_latency     = SLAVE_LATENCY;
    gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;

    err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
    APP_ERROR_CHECK(err_code);

    ////// Added for bonding password //////
    //passkey_opt.gap_opt.passkey.p_passkey = &passkey[0];
    //err_code = sd_ble_opt_set(BLE_GAP_OPT_PASSKEY, &passkey_opt);
    //APP_ERROR_CHECK(err_code); 
    ////// Added for bonding password //////
}


/**@brief Function for initializing the GATT module.
 */
static void gatt_init(void)
{
    ret_code_t err_code = nrf_ble_gatt_init(&m_gatt, NULL);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling Queued Write Module errors.
 *
 * @details A pointer to this function will be passed to each service which may need to inform the
 *          application about an error.
 *
 * @param[in]   nrf_error   Error code containing information about what went wrong.
 */
static void nrf_qwr_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}


/**@brief Function for initializing services that will be used by the application.
 *
 * @details Initialize the Glucose, Battery and Device Information services.
 */
static void services_init(void)
{
    ret_code_t         err_code;
    ble_gls_init_t     gls_init;
    ble_dis_init_t     dis_init;
    ble_bas_init_t     bas_init;
    nrf_ble_qwr_init_t qwr_init = {0};

    // Initialize Queued Write Module.
    qwr_init.error_handler = nrf_qwr_error_handler;

    err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
    APP_ERROR_CHECK(err_code);

    // Initialize Glucose Service - sample selection of feature bits.
    memset(&gls_init, 0, sizeof(gls_init));

    gls_init.evt_handler          = NULL;
    gls_init.error_handler        = service_error_handler;
    gls_init.feature              = 0;
    gls_init.feature             |= BLE_GLS_FEATURE_LOW_BATT;
    gls_init.feature             |= BLE_GLS_FEATURE_TEMP_HIGH_LOW;
    gls_init.feature             |= BLE_GLS_FEATURE_GENERAL_FAULT;
    gls_init.is_context_supported = false;

    // Here the sec level for the Glucose Service can be changed/increased.
    gls_init.gl_meas_cccd_wr_sec = SEC_JUST_WORKS;
    gls_init.gl_feature_rd_sec   = SEC_JUST_WORKS;
    gls_init.racp_cccd_wr_sec    = SEC_JUST_WORKS;
    gls_init.racp_wr_sec         = SEC_JUST_WORKS;

    err_code = ble_gls_init(&m_gls, &gls_init);
    APP_ERROR_CHECK(err_code);

    // Initialize Battery Service.
    memset(&bas_init, 0, sizeof(bas_init));

    // Here the sec level for the Battery Service can be changed/increased.
    bas_init.bl_rd_sec        = SEC_OPEN;
    bas_init.bl_cccd_wr_sec   = SEC_OPEN;
    bas_init.bl_report_rd_sec = SEC_OPEN;

    bas_init.evt_handler          = NULL;
    bas_init.support_notification = true;
    bas_init.p_report_ref         = NULL;
    bas_init.initial_batt_level   = 100;

    err_code = ble_bas_init(&m_bas, &bas_init);
    APP_ERROR_CHECK(err_code);

    // Initialize Device Information Service.
    memset(&dis_init, 0, sizeof(dis_init));

    ble_srv_ascii_to_utf8(&dis_init.manufact_name_str, MANUFACTURER_NAME);

    ble_srv_ascii_to_utf8(&dis_init.serial_num_str, MODEL_NUMBER);

    ble_dis_sys_id_t system_id;
    system_id.manufacturer_id            = MANUFACTURER_ID;
    system_id.organizationally_unique_id = ORG_UNIQUE_ID;
    dis_init.p_sys_id                    = &system_id;

    dis_init.dis_char_rd_sec = SEC_OPEN;

    err_code = ble_dis_init(&dis_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing the sensor simulators.
 */
static void sensor_simulator_init(void)
{
    m_battery_sim_cfg.min          = MIN_BATTERY_LEVEL;
    m_battery_sim_cfg.max          = MAX_BATTERY_LEVEL;
    m_battery_sim_cfg.incr         = BATTERY_LEVEL_INCREMENT;
    m_battery_sim_cfg.start_at_max = true;

    sensorsim_init(&m_battery_sim_state, &m_battery_sim_cfg);
}


/**@brief Function for starting application timers.
 */
static void application_timers_start(void)
{
    ret_code_t err_code;

    // Start application timers.
    err_code = app_timer_start(m_battery_timer_id, BATTERY_LEVEL_MEAS_INTERVAL, NULL);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling the Connection Parameter events.
 *
 * @details This function will be called for all events in the Connection Parameters Module which
 *          are passed to the application.
 *          @note All this function does is to disconnect. This could have been done by simply
 *                setting the disconnect_on_fail configuration parameter, but instead we use the
 *                event handler mechanism to demonstrate its use.
 *
 * @param[in] p_evt  Event received from the Connection Parameters Module.
 */
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
    ret_code_t err_code;

    if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
    {
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
        APP_ERROR_CHECK(err_code);
    }
}


/**@brief Function for handling a Connection Parameters error.
 *
 * @param[in] nrf_error  Error code containing information about what went wrong.
 */
static void conn_params_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}


/**@brief Function for initializing the Connection Parameters module.
 */
static void conn_params_init(void)
{
    ret_code_t             err_code;
    ble_conn_params_init_t cp_init;

    memset(&cp_init, 0, sizeof(cp_init));

    cp_init.p_conn_params                  = NULL;
    cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
    cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
    cp_init.max_conn_params_update_count   = MAX_CONN_PARAM_UPDATE_COUNT;
    cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
    cp_init.disconnect_on_fail             = false;
    cp_init.evt_handler                    = on_conn_params_evt;
    cp_init.error_handler                  = conn_params_error_handler;

    err_code = ble_conn_params_init(&cp_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for putting the chip into sleep mode.
 *
 * @note This function will not return.
 */
static void sleep_mode_enter(void)
{
    ret_code_t err_code;;
    err_code = bsp_indication_set(BSP_INDICATE_IDLE);
    APP_ERROR_CHECK(err_code);

    // Prepare wakeup buttons.
    err_code = bsp_btn_ble_sleep_mode_prepare();
    APP_ERROR_CHECK(err_code);

    // Go to system-off mode (this function will not return; wakeup will cause a reset).
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling advertising events.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
    ret_code_t err_code;

    switch (ble_adv_evt)
    {
        case BLE_ADV_EVT_FAST:
            NRF_LOG_INFO("Fast advertising");
            err_code = bsp_indication_set(BSP_INDICATE_ADVERTISING);
            APP_ERROR_CHECK(err_code);
            break; // BLE_ADV_EVT_FAST

        case BLE_ADV_EVT_IDLE:
            sleep_mode_enter();
            break; // BLE_ADV_EVT_IDLE

        default:
            break;
    }
}


/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ret_code_t err_code;

    pm_handler_secure_on_connection(p_ble_evt);

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_DISCONNECTED:
        {
            NRF_LOG_INFO("Disconnected");
            m_conn_handle = BLE_CONN_HANDLE_INVALID;
            // Check if the last connected peer had not used MITM, if so, delete its bond information.
            if (m_peer_to_be_deleted != PM_PEER_ID_INVALID)
            {
                err_code = pm_peer_delete(m_peer_to_be_deleted);
                APP_ERROR_CHECK(err_code);
                NRF_LOG_DEBUG("Collector's bond deleted");
                m_peer_to_be_deleted = PM_PEER_ID_INVALID;
            }
        } break;

        case BLE_GAP_EVT_CONNECTED:
        {
            NRF_LOG_INFO("Connected");
            m_peer_to_be_deleted = PM_PEER_ID_INVALID;
            err_code = bsp_indication_set(BSP_INDICATE_CONNECTED);
            APP_ERROR_CHECK(err_code);
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
            APP_ERROR_CHECK(err_code);
            // Start Security Request timer.
        } break;

        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("PHY update request.");
            ble_gap_phys_t const phys =
            {
                .rx_phys = BLE_GAP_PHY_AUTO,
                .tx_phys = BLE_GAP_PHY_AUTO,
            };
            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } break;

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            NRF_LOG_DEBUG("GATT Client Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
            NRF_LOG_DEBUG("BLE_GAP_EVT_SEC_PARAMS_REQUEST");
            break;

        case BLE_GAP_EVT_PASSKEY_DISPLAY:
        {
            char passkey[PASSKEY_LENGTH + 1];
            memcpy(passkey, p_ble_evt->evt.gap_evt.params.passkey_display.passkey, PASSKEY_LENGTH);
            passkey[PASSKEY_LENGTH] = 0;

            NRF_LOG_INFO("Passkey: %s", nrf_log_push(passkey));
        } break;
        
        case BLE_GAP_EVT_AUTH_KEY_REQUEST:
            NRF_LOG_INFO("BLE_GAP_EVT_AUTH_KEY_REQUEST");
            break;

        case BLE_GAP_EVT_LESC_DHKEY_REQUEST:
            NRF_LOG_INFO("BLE_GAP_EVT_LESC_DHKEY_REQUEST");
            break;

         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));
            break;

        default:
            // No implementation needed.
            break;
    }
}


/**@brief Function for initializing the BLE stack.
 *
 * @details Initializes the SoftDevice and the BLE event interrupt.
 */
static void ble_stack_init(void)
{
    ret_code_t err_code;

    err_code = nrf_sdh_enable_request();
    APP_ERROR_CHECK(err_code);

    // Configure the BLE stack using the default settings.
    // Fetch the start address of the application RAM.
    uint32_t ram_start = 0;
    err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
    APP_ERROR_CHECK(err_code);

    // Enable BLE stack.
    err_code = nrf_sdh_ble_enable(&ram_start);
    APP_ERROR_CHECK(err_code);

    // Register a handler for BLE events.
    NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
}


/**@brief Function for handling events from the BSP module.
 *
 * @param[in]   event   Event generated by button press.
 */
static void bsp_event_handler(bsp_event_t event)
{
    ret_code_t err_code;

    switch (event)
    {
        case BSP_EVENT_SLEEP:
            sleep_mode_enter();
            break; // BSP_EVENT_SLEEP

        case BSP_EVENT_DISCONNECT:
            err_code = sd_ble_gap_disconnect(m_conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            if (err_code != NRF_ERROR_INVALID_STATE)
            {
                APP_ERROR_CHECK(err_code);
            }
            break; // BSP_EVENT_DISCONNECT

        case BSP_EVENT_WHITELIST_OFF:
            if (m_conn_handle == BLE_CONN_HANDLE_INVALID)
            {
                err_code = ble_advertising_restart_without_whitelist(&m_advertising);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }
            break; // BSP_EVENT_WHITELIST_OFF

        case BSP_EVENT_KEY_1:
            read_glucose_measurement();
            break; // BSP_EVENT_KEY_1

        default:
            break;
    }
}


/**@brief Function for the Peer Manager initialization.
 */
static void peer_manager_init(void)
{
    ble_gap_sec_params_t sec_param;
    ret_code_t           err_code;

    err_code = pm_init();
    APP_ERROR_CHECK(err_code);

    memset(&sec_param, 0, sizeof(ble_gap_sec_params_t));

    // Security parameters to be used for all security procedures.
    sec_param.bond           = SEC_PARAM_BOND;
    sec_param.mitm           = SEC_PARAM_MITM;
    sec_param.lesc           = SEC_PARAM_LESC;
    sec_param.keypress       = SEC_PARAM_KEYPRESS;
    sec_param.io_caps        = SEC_PARAM_IO_CAPABILITIES;
    sec_param.oob            = SEC_PARAM_OOB;
    sec_param.min_key_size   = SEC_PARAM_MIN_KEY_SIZE;
    sec_param.max_key_size   = SEC_PARAM_MAX_KEY_SIZE;
    
    sec_param.kdist_own.enc  = 0;
    sec_param.kdist_own.id   = 0;
    sec_param.kdist_peer.enc = 0;
    sec_param.kdist_peer.id  = 0;
   

    err_code = pm_sec_params_set(&sec_param);
    APP_ERROR_CHECK(err_code);

    err_code = pm_register(pm_evt_handler);
    APP_ERROR_CHECK(err_code);
}


/**@brief Clear bond information from persistent storage.
 */
static void delete_bonds(void)
{
    ret_code_t err_code;

    NRF_LOG_INFO("Erase bonds!");

    err_code = pm_peers_delete();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing the Advertising functionality.
 *
 * @details Encodes the required advertising data and passes it to the stack.
 *          Also builds a structure to be passed to the stack when starting advertising.
 */
static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advertising_init_t init;

    memset(&init, 0, sizeof(init));

    init.advdata.name_type               = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance      = true;
    init.advdata.flags                   = BLE_GAP_ADV_FLAGS_LE_ONLY_LIMITED_DISC_MODE;
    init.advdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.advdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;

    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}


/**@brief Function for initializing buttons and leds.
 *
 * @param[out] p_erase_bonds  Will be true if the clear bonding button was pressed to wake the application up.
 */
static void buttons_leds_init(bool * p_erase_bonds)
{
    ret_code_t err_code;
    bsp_event_t startup_event;

    err_code = bsp_init(BSP_INIT_LEDS | BSP_INIT_BUTTONS, bsp_event_handler);
    APP_ERROR_CHECK(err_code);

    err_code = bsp_btn_ble_init(NULL, &startup_event);
    APP_ERROR_CHECK(err_code);

    *p_erase_bonds = (startup_event == BSP_EVENT_CLEAR_BONDING_DATA);
}


/**@brief Function for initializing the nrf log module.
 */
static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_DEFAULT_BACKENDS_INIT();
}


/**@brief Function for initializing power management.
 */
static void power_management_init(void)
{
    ret_code_t err_code;
    err_code = nrf_pwr_mgmt_init();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling the idle state (main loop).
 *
 * @details If there is no pending log operation, then sleep until next the next event occurs.
 */
static void idle_state_handle(void)
{
    ret_code_t err_code;

    err_code = nrf_ble_lesc_request_handler();
    APP_ERROR_CHECK(err_code);

    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}


/**@brief Function for starting advertising.
 */
static void advertising_start(bool erase_bonds)
{
    if (erase_bonds == true)
    {
        delete_bonds();
        // Advertising is started by PM_EVT_PEERS_DELETE_SUCCEEDED event.
    }
    else
    {
        ret_code_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);

        APP_ERROR_CHECK(err_code);
    }
}


/**@brief Function for application main entry.
 */
int main(void)
{
    bool erase_bonds;

    // Initialize.
    log_init();
    timers_init();
    buttons_leds_init(&erase_bonds);
    power_management_init();

    // Set Password Key
    ble_stack_init();
    set_static_passkey();
    
    // Initialize
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init();
    sensor_simulator_init();
    conn_params_init();
    peer_manager_init();

    // Start execution.
    NRF_LOG_INFO("Bonding program started.");
    application_timers_start();
    advertising_start(erase_bonds);

    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

I didn't understand whats the wrong with the code or I am doing in wrong way.Please help me to archive my goal.

Thank you advanced.

[Einar Thorsrud]

Hi,

My objective is The nRF52840 dongle should connect with nRF Connect App after getting the passkey reply from nRF Connect App otherwise it should not connect.

This is not possible. The establishment of a BLE connection is not related to the passkey concept, which can be used to provide authenticity (man in the middle protection). That is a concept of pairing, so the passkey exchange always happens during pairing (if used).

That said, you could make it so that all your characteristics require security so that it would be impossible to do anything without pairing. You could also request pairing and disconnect if it does not happen.

[prayuktibid]

Thank you Mr. Einar. 

So, this is not possible but I would like to know that Is there any produce by which I can ensure the peripheral device will connect with a particular central device? 

In case of central device we can do filtering by name, by UUID, by mac id etc... So that the central device connect only those devices which are in filter list. In peripheral device Can I do same thing? 

Actually my primary objective is not security its secondary, my primary and main objective is peripheral should connect the particular central device which I want. I think you got my point.

My humble request to you please suggest me some method by which I can achieve my goal.

Thank you advanced.

[Einar Thorsrud]

Hi,

prayuktibid said:

So, this is not possible but I would like to know that Is there any produce by which I can ensure the peripheral device will connect with a particular central device? 

If the devices are bonded beforehand, then this is standardized. You could use whitelisting, where only a central with a specific MAC address (or a specific IRK address if it uses resolvable addresses, as mobile phones do).

prayuktibid said:

In case of central device we can do filtering by name, by UUID, by mac id etc... So that the central device connect only those devices which are in filter list. In peripheral device Can I do same thing? 

Yes. The same whitelisting concept can be used for both central and peripheral devices. But again, you need to bond in that case (or at least know the MAC address and/or IRK address in advance).

prayuktibid said:

Actually my primary objective is not security its secondary, my primary and main objective is peripheral should connect the particular central device which I want.

I see. This leaves you several options, but which option makes more sense depends on some factors that have not been discussed:

• Will you pair the two devices in production somehow, or should the matching of two specific devices be done later in the field?
• Do your devices have buttons, display or anything else? What does it have?
• What level of security do you require? Is it acceptable that an attacker can make the devices connect to the wrong device?

If you produce two and two devices to work together, then you can do pairing (or a similar concept) during production, and in that case, it would be secure and user-friendly. If you don't pair them in production, then you need another mechanism, such as suggested below. It will not be as secure, but it may be good enough, depending on your requirements:

• Use a button press to start advertising, and only advertises for a short while. This makes it unlikely that another device is close by advertising at the same time. This is the approach typically used with HID mice. This is not suitable in an environment when many devices might do this at the same time, and an attacker can easily act as peripheral making the central connect to it instead.
• Use RSSI to only allow connections from devices with a high RSSI (assumes close by). Disconnect if RSSI of the first received packet is low. This is not very accurate though and might decrease user-friendliness.
• Combination of the above in order to increase security (but it will still not be good).

[prayuktibid]

Thank you Mr. Einar,

Are 'filtering' and 'whitelisting'  is same thing? I have bit confusion among these two thing.

Einar Thorsrud said:

Will you pair the two devices in production somehow, or should the matching of two specific devices be done later in the field?

Basically in field.

Einar Thorsrud said:

Do your devices have buttons, display or anything else? What does it have?

No button, no display and no keyboard. The peripheral device(assume nrF52840 dongle) should connect automatically with the central device(assume another nrF52840 dongle) whenever it comes withing the range.

Einar Thorsrud said:

What level of security do you require? Is it acceptable that an attacker can make the devices connect to the wrong device?

Obviously, I don't want to connect with wrong device that is why I want to connect with the particular central device but data is not important cause I want to control hardware(On/OFF type) on peripheral device from the central device.

Einar Thorsrud said:

If you produce two and two devices to work together, then you can do pairing (or a similar concept) during production, and in that case, it would be secure and user-friendly. If you don't pair them in production, then you need another mechanism, such as suggested below. It will not be as secure, but it may be good enough, depending on your requirements:

I want to produce central devices and peripheral devices by some particular name. Suppose I make all central device's "DEVICE_NAME = Master" and peripheral device's "DEVICE_NAME = Slave". I want every "Slave"  should connect with any "Master" and vice verse but no other devices which have different name. The "Slave" should give provision to connect with it if the device name "Master" is matched otherwise no connection will be established.  I want to give a generic name or uuid for all centrals and peripherals.

Thank you advanced.

[Einar Thorsrud]

Hi,

prayuktibid said:

Are 'filtering' and 'whitelisting'  is same thing? I have bit confusion among these two thing.

Not necessarily. You can filter on anything. Whitelisting in BLE is essentially filtering on the MAC address (either directly if it is static or by resolving it to an IRK).

prayuktibid said:

No button, no display and no keyboard. The peripheral device(assume nrF52840 dongle) should connect automatically with the central device(assume another nrF52840 dongle) whenever it comes withing the range.

I see. So it is impossible to make a secure solution in this case, but that is probably not needed anyway.

prayuktibid said:

Obviously, I don't want to connect with wrong device that is why I want to connect with the particular central device

 I understand. But what I wanted to know what how important it was to make sure that this could never happen. Since you want to do this in the field and don't have any I/O capability or another side channel, it is not possible to make it secure from attackers. But that is hopefully not a concern.

prayuktibid said:

I want to produce central devices and peripheral devices by some particular name. Suppose I make all central device's "DEVICE_NAME = Master" and peripheral device's "DEVICE_NAME = Slave". I want every "Slave"  should connect with any "Master" and vice verse but no other devices which have different name. The "Slave" should give provision to connect with it if the device name "Master" is matched otherwise no connection will be established.  I want to give a generic name or uuid for all centrals and peripherals.

 I see. The central can choose to connect to just peripherals with the "correct" name, as long as the peripheral puts the name in the advertising packet. For the peripheral, it does not know anything about the central until after it has connected, but you could make the peripheral read the central name after the connection, and disconnect if the name is incorrect.

[prayuktibid]

Thank you Mr. Einar,

Einar Thorsrud said:

 I understand. But what I wanted to know what how important it was to make sure that this could never happen. Since you want to do this in the field and don't have any I/O capability or another side channel, it is not possible to make it secure from attackers. But that is hopefully not a concern.

I got your point. What If I add a single tactile button with the BLE module and I can  start advertising and scanning by pressing the button then Can I achieve some security level?

Einar Thorsrud said:

 I see. The central can choose to connect to just peripherals with the "correct" name, as long as the peripheral puts the name in the advertising packet. For the peripheral, it does not know anything about the central until after it has connected, but you could make the peripheral read the central name after the connection, and disconnect if the name is incorrect.

Thank you, I will try on it and let you know.

[Einar Thorsrud]

Hi,

prayuktibid said:

What If I add a single tactile button with the BLE module and I can  start advertising and scanning by pressing the button then Can I achieve some security level?

It would be better from a usability perspective since the likelihood of you actually connecting to the correct device will increase (since there are probably fewer advertisers, and you can typically advertise with shorter advertising interval when the duration is short). However, it would not increase security, since an attacker would still be able to connect (or be connected to) instead.

It is not even theoretically possible with authentication without a form of side-channel, but the side-channel could in principle be anything (typically either human via button/display, NFC, pre-provisioned in flash etc.).

[prayuktibid]

Thank you