Bluetooth LE pre-pairing for Windows

[CY]

Hi,

Recently, I am studying the blog as the link below:

https://docs.microsoft.com/en-us/windows-hardware/design/component-guidelines/bluetooth-prepairing

We would like to do pre-paired in factory.

As you might see from the website, it has mentioned that as peripheral it is required to follow the rule.

Peripheral

• Bluetooth LE
• Store for Device ID (hashed from Bluetooth Address) & TK value
• Custom Advertisement (defined below)

I am unclear about the Device ID description.

DeviceID: uniquely identify a supporting device and should be 8 bytes in length to avoid device conflicts.

From the description it said it should be 8 bytes, but the BT address should be 6 bytes  (0xC7BB9B6D8833).

 I suppose I am misunderstanding. Could you give me some guide?

And I would like to know whether I could check and set the the Device ID as well as the temporary key (SMP TK)?

If there is any API, could you help me to indicate?

Thanks.

[CY]

I suppose to meet the pre-paired function, it should be static TK.

So will it be the same way to achieve the key? Or other function instead of link_secure_central_encryption?

And I just confused with the "Central".

If my device is peripheral device, could it worked?

[CY]

I just found the related location as below:

ble_gap.h

/**@brief GAP LE Secure Connections OOB data. */
typedef struct
{
ble_gap_addr_t addr; /**< Bluetooth address of the device. */
uint8_t r[BLE_GAP_SEC_KEY_LEN]; /**< Random Number. */
uint8_t c[BLE_GAP_SEC_KEY_LEN]; /**< Confirm Value. */
} ble_gap_lesc_oob_data_t;

peer_manager_types.h

/**@brief Data associated with a bond to a peer.
 */
typedef struct
{
    uint8_t           own_role;    /**< @brief The BLE role of the local device during bonding. See @ref BLE_GAP_ROLES. */
    ble_gap_id_key_t  peer_ble_id; /**< @brief The peer's Bluetooth address and identity resolution key (IRK). */
    ble_gap_enc_key_t peer_ltk;    /**< @brief The peer's long-term encryption key (LTK) and master ID. */
    ble_gap_enc_key_t own_ltk;     /**< @brief Locally generated long-term encryption key (LTK) and master ID, distributed to the peer. */
} pm_peer_data_bonding_t;

How could I change the BT address and TK value?

[CY]

Hi Susheel,

I just reviewed the nfc_pairing sample for finding the clue of OOB.

Since that OOB must use the below information:

I supposed it is possible to set a static TK in nRF52 because the below image:

 

But not sure where could I set, I cannot not link to the definition of TK.

[Wedy Hsiao]

Hi Susheel,

I also have the same question that how to set the static TK in the hid_keyboard project.