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

Attachment: a5_3.pcapng
Description: a5_3.pcapng

Attachment: a5_1.pcapng
Description: a5_1.pcapng

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