24 May
2012
24 May
'12
10:26 a.m.
Hi,
Is it possible to crate your own SIM's ?
As far as i can see, these are just small smartcards.
And as such, thse can be filled with the tools that come along with
OpenSC.
I presume the SIM's contain a number of EF's and DF's
One set that thighs a SIM to a specific operator (making it possible to
SIM-lock a handy)
And another set of EF's that identifies a specific user.
Yes, they're essentially simple smartcard and as long as you have the
proper file and use the proper class byte, that will work.
However, SIM are also responsible for the execution of the A3A8
authentication algorithm through a special 'RUN GSM ALGORITHM' command
and your smartcard must implement it.
Within the DB of the operator, the relation between
the SIM-identifier
and the specific user (with his 06-number and other info) is made.
(I know that the sim itself is not unique, because a college had a
malfuntioning SIM, and it was replaced by another one, with the same
content)
Yes. The MISDN (phone number) has no relation to the IMSI (SIM
identity) except inside the operator.
1) can you burn your own sim's
Yes.
See http://shop.sysmocom.de/t/sim-card-related/sim-cards for
programmable simcards.
See http://cgit.osmocom.org/cgit/pysim/ for an utility to program those.
And finally see http://cgit.osmocom.org/cgit/osmo-cos/ for the
beginning of a fully opensource smartcard OS you could use to
implement SIM.
2) would there be any objections to have, beside de
GSM-info, also a
certificate
I would think so.
AFAICT the specs says you have to respond to certain command, but it
doesn't say you can't answer to some additional ones not in the specs.
3) could you "clone" an existing SIM?
You can't read the secret key, also the algoritmh chosen by your
operator for A3A8 can be variable (and not all are known).
So ... you can make a copy that includes everything except those but
it will obviously not work.
With regard to the last one: If i buy a couple of
prepaid-sims from a
operator, would it be possible to extract that info, and put it along
with my own certificates on a sim of my own?
See above : No.
Cheers,
Sylvain