S110 and secure connection

[Mehdi Chafik]

Hello,

I use stack S110 V7.1.0 on nRF51822 (the device is a remote with 4 buttons). Currently the remote send advertising frame with the pressed button into the data, we would like to securise the connection.

1. I would like to use rolling address. In Hal_Ble_GapParamInit() I have this code:

gap_address.addr_type = BLE_GAP_ADDR_TYPE_RANDOM_PRIVATE_RESOLVABLE; err_code = sd_ble_gap_address_set(BLE_GAP_ADDR_CYCLE_MODE_AUTO, &gap_address); APP_ERROR_CHECK(err_code);

ble_opt_t opt = {0}; opt.gap_opt.privacy.interval_s = 60; err_code = sd_ble_opt_set(BLE_GAP_OPT_PRIVACY, &opt); APP_ERROR_CHECK(err_code);

The address change on each advertising frame not on each 60s (err_code is equal 0). What's is the correct syntax to use?

2. On the gateway (linux device running bluez) I need to identify this remote, so the first time the remote is detected I need to perform a pairing (key generation and exchange) to be able the next time to decode the rolling mac address. Do you have sample code to do this (nRF side)?

This post said S130 is need, but this one said it's possible on S110 v7.x.

Best regards Jerome

[Petter Myhre]

On each advertising frame? Are you sure? How are you checking? I need to look into which SDK version that supports bonding with IRK. Are you tied to S110 v7.x? Do you have a good reason for not using S110 v8 or S130?

[Mehdi Chafik]

Not exactly on each. To check I use hcitool with and without --duplicate. I found the address change each time I call sd_ble_gap_adv_start. Maybe it's the problem? I start and stop advertising because it's a remote with CR2032 battery and I doesn't want to use a lot of power. I also change the interval between advertising frames for the same reason (depending if the remote move or not).

Currently all remote sold have S110 V7.1.0 and if it's possible we prefer to keep this version to avoid OTA of softdevice and the application. Maybe we can switch to S110 V8 if needed but for S130 we need to check if we have enough memory (S130 is bigger I suppose) and if it's possible to perform OTA on existing device to switch from S110 to S130.

[Petter Myhre]

The address will change every time you call sd_ble_gap_adv_start() independent of interval.

[Mehdi Chafik]

Do you have sample code with S110 v8 or S130 v2 that use rolling address with pairing?

[Petter Myhre]

Not really, but we have a many examples that support pairing. I believe they should work with "rolling" address as well.