Hi Jan, Do you have traces of the attach/authentication? It seems like for some reason your MS don't like A5/3, because they are supposed to reply with Cipher Mode Complete. So top of my head I had the thought there might be something wrong with the initial establishment of the keys.
Cheers, Domi > 2018. márc. 6. dátummal, 10:58 időpontban Bruckner Jan (ETAS-SEC/ECT-Mu) > <jan.bruck...@escrypt.com> írta: > > Dear list, > > I’m having trouble using the A5/3 encryption in my setup. A5/1 works > perfectly fine [attachment a5_1.pcapng]. As soon as I switch to A5/3 and e.g. > send an SMS, the last valid message I see in the Wireshark traces of the > GSMTAP of osmo-bts-trx is the Ciphering Mode Command requesting A5/3. After > that, several messages arrive at the bts, but it seems like it can’t make any > sense of them. The MS repeatedly tries to send the SMS but never succeeds > [attachment a5_3.pcapng]. Both MSs are connected to the same bts. > > According to the Classmarks of all MSs, A5/1 as well as A5/3 are supported. > This is my Setup: > - USRP N210 > - osmo-trx > - osmo-bts-trx > - osmo-nitb > - osmo-pcu > - osmo-sgsn > - osmo-ggsn > I’m using a Debian 9 VM and tried both the packages from osmocom-latest as > well as osmocom-nightly. > The MSs I’ve tested are two Nexus 6 and one Samsung Galaxy S I9000. All three > with sysmocom nano USIMs. > > Could the decryption at the bts be incorrect? Has anyone tested/used it > recently? > I’ll be happy to provide additional information if needed. > > Thanks, > Jan > <a5_3.pcapng><a5_1.pcapng>