Can't bond from pc-ble-driver-py: "Creating invalid shared secret to make LESC fail"

RE: Can't bond from pc-ble-driver-py: "Creating invalid shared secret to make LESC fail"

Vidar Berg — Mon, 17 Feb 2020 09:55:52 GMT

It is unfortunate that you had to spend all this time just to find out it is not supported. I have created an internal JIRA ticket for this suggestion. Thanks for your feedback.

RE: Can't bond from pc-ble-driver-py: "Creating invalid shared secret to make LESC fail"

charles — Fri, 14 Feb 2020 14:40:53 GMT

Thanks for the response and clarification. It's frustrating that I have to open a Devzone ticket for this, when simple documentation on the pc-ble-driver / pc-ble-driver-py GitHub project landing pages would have saved us days of struggle.

Please consider documenting known shortcomings like this clearly to save both my time and yours.

RE: Can't bond from pc-ble-driver-py: "Creating invalid shared secret to make LESC fail"

Vidar Berg — Fri, 14 Feb 2020 12:35:02 GMT

Hi Charles,

As can be seen from the message sequence chart here: Pairing: Just Works, the application is expected to respond with the public key when it is receiving the BLE_GAP_EVT_LESC_DHKEY_REQUEST event from the Softdevice. Unfortunately, that event is currently not being handled in the official pc-ble-driver/pc-ble-driver-py release. So the application needs to include a crypto library and perform the ECC computations for the Softdevice in order to support LESC.

Please take a look at this patch made by one of my colleagues for an older version of pc-ble-driver-py and see if it's something you can use as a reference: https://github.com/stianrh/ble_driver/compare/113c183...6f7079d

nRF desktop uses the JS wrapper around the pc-ble-driver and is not yet updated to use v5.

Best regards,

Vidar

RE: Can't bond from pc-ble-driver-py: "Creating invalid shared secret to make LESC fail"

charles — Thu, 13 Feb 2020 18:17:28 GMT

A colleague of mine noticed that the nRF Connect desktop app flashes the nrf52840 USB dongle that uses v3 of the SoftDevice 132 api. The pc-ble-driver-py version uses v5 of the SoftDevice 132 api. We can't figure out a way to do an apples-to-apples test where the exact same firmware and SoftDevice on the nRF52840 dongle succeeds in nRF Connect but fails in pc-ble-driver-py.