RE: Is there a way to access/print the Long Term Key (LTK) to help with sniffer capture?

JeremyM — Mon, 08 Apr 2024 19:20:16 GMT

Thanks!

The following text is probably more for myself and other readers new to Kconfig settings, but I had some trouble figuring out where to make this change. After some trial and error, I think the place to make it is in \v2.6.0\nrf\applications\nrf5340_audioprj.conf .

Initially I tried changing line 998 in \v2.6.0\zephyr\subsys\bluetooth\host\Konfig to add =y, but that causes a build error.

I tried adding it early in the \v2.6.0\nrf\applications\nrf5340_audio\Kconfig and that shows more pairing information, but not the LTKs.

After adding the line to \v2.6.0\nrf\applications\nrf5340_audioprj.conf (near the start of the file, but not on a #comment line), I do see the LTK, the line looks something like

GW [00:00:02.015,869] <inf> bt_keys: SC LTK: 0x...

RE: Is there a way to access/print the Long Term Key (LTK) to help with sniffer capture?

ivan iushkov — Sun, 07 Apr 2024 08:52:03 GMT

KConfig option

CONFIG_BT_LOG_SNIFFER_INFO=y

can be used perhaps

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.4.3/kconfig/index.html#CONFIG_BT_LOG_SNIFFER_INFO

Another useful option is using debug keys:
CONFIG_BT_USE_DEBUG_KEYS=y
It forces Bluetooth stack of Zephyr to use hard-coded debug keys which allow sniffer to decrypt trafffic automatically

developer.nordicsemi.com/.../index.html