Hi Mychaela,
On Wed, Feb 03, 2021 at 11:01:19PM -0800, Mychaela Falconia wrote:
My ideal dream SIMs for running my own GSM/2G network
(a network whose
sole purpose is to provide service to classic GSM/2G phones) would be
those that have only the classic SIM application, and NO USIM or ISIM.
And I would really like for USIM and ISIM to be truly-truly Not There,
rather than just hidden from EF_DIR.
In theory, you should be able to remove the respective applications from
most java based cards with the right credentials via SCP02. Did you
try?
I am currently in negotiations with Grcard in China,
who are telling
me that they can supply me with such SIMs, and at an affordable price
too, without a cost-prohibitive MOQ.
sysmocom can certainly also provide such cards, should you have a
related requirement. It requires creating a card profile without
ADF.USIM + ADF.ISIM, which certainly can be done. I think the cards
will still react to APDUs with CLA != 0xA0, but you would not have any
ADF.USIM or ADF.ISIM present.
One clear disadvantage of using SIM without USIM functionality even on a
2G radio network is that you can never use mutual authentication between
network and phone (which is a pure protocol related aspect, so it could
be implemented in any phone/baseband whose software can be modified -
including FreeCalypso.
Regards,
Harald
--
- Harald Welte <laforge(a)osmocom.org>
http://laforge.gnumonks.org/
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"Privacy in residential applications is a desirable marketing option."
(ETSI EN 300 175-7 Ch. A6)