On Wed, Mar 07, 2018 at 11:14:25AM +0000, Bruckner Jan (ETAS-SEC/ECT-Mu) wrote:
I just tested that. It does not change the behavior. As soon as I switch to A5/3 the BTS never receives a Ciphering Mode Complete
The details there are that the Ciphering Mode Command is asking to start ciphering on the air, and the Ciphering Mode Complete is already sent ciphered. So it might be received, but the received data may be discarded as gibberish.
It would be good if anyone out there could try to reproduce the error using an SDR based BTS.
You're also welcome to create a ticket on the osmocom.org redmine.
~N