OOB key for sniffer

[abe]

Hi, I'm on final development stage of my custom board. I'm using nRF52840 with nRF5 SDK v15.0.0 and S140 SoftDevice v6.0.0.
I need to trace the over-the-air communication with customer BLE Central console, that collect some BLE peripherals.
I see on nRF Sniffer documentation the detail here below. 
My question: how can I find the OOB key?
Many thanks for answer
Best regards
.ab

[Sigurd]

Hi,

To get the OOB key you will need to output the OOB key from the application in some way, for instance print it to UART by using NRF_LOG_INFO().

[abe]

Ok, this was already clear for me, but the question is where I can find the OOB key data?
Inside what variable or structure of Sofdevice and/or other nRF SDK library?

[Sigurd]

The SoftDevice will request the key in the BLE_GAP_EVT_AUTH_KEY_REQUEST event, and you provide the key with the function sd_ble_gap_auth_key_reply(). So print the key right after or before the application provides the key with sd_ble_gap_auth_key_reply().