[Gsmmap] A5/1 - A5/3

Luca Melette luca at srlabs.de
Tue Jan 7 16:00:18 CET 2014

Hi Alex,

> How is it possible to see which encryption algorithm is in use?
> Is there any AT+ SIM command or any command that can be issued to the
> SIM to return the setting?

In my experience, this is very hard to get, since it's not decided
by the mobile or modem you have on your hands.

These user devices support a set of algorithms (A5/0 to A5/3), but the
actual one used over the air is decided by the network each time
you establish a channel. And sometimes the encryption is not even used.

I doubt AT commands are extended to that point, but some diagnostic
protocols offer this information.

The easier source are radio logs/modem debug information, that we are
asking all of you to submit to gsmmap.org so that we can create a
more advanced map, covering also 3G and GPRS.

Whenever you have an xgoldmon compatible mobile, you can get those
files and possibly extract the radio signalling with Tobias' tool:



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