NFC pairing NFC_PAIRING_MODE_OOB

RE: NFC pairing NFC_PAIRING_MODE_OOB

run_ar — Tue, 18 Jun 2019 11:02:51 GMT

Well, you can probably do a lot of different things with NFC. We do have a couple of examples:

Experimental: BLE Pairing Using NFC - Peripheral Reference Example

Experimental: HID Keyboard Application with BLE pairing using NFC

Experimental: Heart Rate Application with BLE Pairing Using NFC Pairing Library

Seems we are supporting proper handover including the ble address. So another user should not be able to connect without having the oob key.

RE: NFC pairing NFC_PAIRING_MODE_OOB

Andreas48752 — Fri, 14 Jun 2019 12:06:15 GMT

Sorry, but I have to ask again:

Imaging the device is not advertising until NFC is touched.
When NFC is touched OOB key is transfered over NFC and advertising is enabled in connectable mode (which I asume "nfc_ble_pair_init" from nfc_ble_pair_lib does).
In this state the mobile shows the message "do you want to pair with device X". When the user takes a few seconds to decide if he wants to pair another device could connect without having the OOB key?

Then connection would not be encrypted but without a whitelist it is possible for everyone to connect until the mobile makes the connection and advertising is disabled automatically?

Did I understand that correctly?

Thanks.

RE: NFC pairing NFC_PAIRING_MODE_OOB

run_ar — Fri, 14 Jun 2019 11:44:21 GMT

Hi,

NFC is used to exchange the OOB key. By default it does not create a whitelist for advertising, so if you advertise in connectable mode, all central devices can connect. Possible solutions would be to advertise in non connectable mode (or not advertise at all) until NFC is present. Then start advertising in connectable mode. After you have bonded to a device you can use a whitelist when advertising to stop other central from connecting, but remember that it's trivial for an attacker to copy the address, so the whitelist cannot be used for authentication, only to limit connections.