NFC pairing - what is OOB data

[Matthew K]

Hi guys. When reading the OOB pairing example,

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/peripheral_nfc_pairing/README.html

"This sample can exchange OOB data with an NFC Forum Polling device"

I'm having trouble understanding this example.

What exactly is this "OOB data"? Like Long Term Key (LTK), IRK, ERK are the OOB data?

My smartphone is Galaxy S20 (Android 12) so the LE Secure Connection pairing/bonding should be supported.

Eventually, I want the nRF52840 to bond with my Android phone using NFC/OOB.

I'm using nRF52840 DK. What peripheral SoftDevice function is called that uses this OOB data?

Also, does this SoftDevice function have to be called before the connection with the BLE central device?

Thanks for your help!

[Simonr]

Hi

Seems like Bluetooth Secure Simple Pairing is the go-to for information on the OOB pairing and BLE compatibility.

Best regards,

Simon

[Matthew K]

Hi, Simon. I think I finally understood, hopefully:

[Q] OOB data are
confirmation value and random value
is this correct?

Are these values always 256-bit?

[Q] About "should not be necessary to use the nRF Connect Mobile app to do OOB as this is part of the NFC and BLE spec.",

I read that there are 3 possible scenarios:
1) Both smartphone and the nRF52 peripheral provides OOB data via NFC
2) Only the smartphone provides the OOB data via NFC
3) Only the nRF52 peripheral provides the OOB data via NFC

When using Android native OOB NFC (not using any Android mobile OOB NFC app),
which "scenario" is used?

Are both Android and nRF52 provide

ra, CA, rb, Cb

with the native OOB NFC?

Thanks for your help.