changing key as security feature in osmocom?

[Tim Ehlers]

Hi,

I just saw the talk of Karsten Nohl at 28C3 and ask myself if it would be 
possible to trigger a new session key (KC) after every e.g. Call,SMS,USSD 
and silent SMS :) for next event.

I mean it seems that e.g. in O2 Network in germany the key never changes, 
only when turning off and on the phone and after many events.

For O2 it maybe enough to reconnect to the network? I really would like to 
get a somewhat secure GSM connection for my anchor mobile at home 
(remotely controlled from the PC) for my nationwide homezone (BWHZ), 
using osmocombb. :)

Has anyone a suggestion, idea?

Thanks

Tim