Do OpenPGP cards support T=0?

Grant Olson kgo at
Sun Mar 6 02:00:28 CET 2011

It looks like they don't, but I'm just trying to get confirmation.

Background: I got a hold of an ACR83, a pinpad enabled reader with a
sexy form factor.  It was supposed to be CCID compliant, but it's not
quite.  I've been trying to get driver working.  A minor modification to
libccid enabled some basic CCID communication.

But then it hangs when trying to negotiate the IFSD, the variable data
packet size for T=1 transmissions.  Over on the MUSCLE-card list, it was
suggested I tried a card that ran in T=0 mode.

I thought the OpenPGP smartcard spec said that cards should support both
versions of APDU.  I hacked my local copy of scdaemon
(STABLE-BRANCH-2-0) to always force the T=0 protocol.  Then I get error
messages that the card doesn't support T=0 on both my ACR83 and my
working SCM-3310.  Re-reading the spec, I don't think T=0 protocol is
actually required on the card.

But if anyone can verify that this is indeed true, that the ZeitControl
card doesn't support T=0, and I didn't screw up in my hacked version of
scdaemon, I'd appreciate it.


"Look around! Can you construct some sort of rudimentary lathe?"

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