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Wireshark-dev: Re: [Wireshark-dev] ISO 7816 vs GSM SIM dissector

From: Martin Kaiser <lists@xxxxxxxxx>
Date: Thu, 19 Aug 2021 13:35:22 +0200
Hi Pascal and Stig,

Thus wrote Pascal Quantin (pascal@xxxxxxxxxxxxx):

> Le mer. 18 ao�t 2021 � 13:51, Stig Bj�rlykke <stig@xxxxxxxxxxxxx> a �crit :

> > Hi,

> > Does anyone know the difference between the ISO 7816 dissector and the GSM
> > SIM dissector?

amongst other things, the iso7816 dissector includes the ATR (answer to
reset). This seems to be used by a couple of other dissectors as well.

> > For me it looks like they are handling the same PDUs, but both are
> > incomplete in different ways.


> You are correct. Both were done by different developers for different
> purposes (Martin added the generic ISO 7816 dissector after Harald added
> the GSM SIM one). SIM or USIM application is just one of the many
> applications that can run on a smartcard. Note that the 3GPP specs override
> the ISO specs, so the decoding of the elementary files could differ as far
> as I can remember

I guess that specific applications of ISO 7816, such as GSM-SIM or
payment cards, redefine not only elementary files (payload) but also
some header fields and status codes. We'd have very few common items
across all iso 7816 use cases.

Nevertheless, I suppose that gsm_sim and iso7816 could be merged if we
wanted to.

Best regards,
Martin