Getting the SCM SCT3511 to work

Peter Lebbing peter at
Mon Sep 21 18:58:27 CEST 2009

In a previous message [1] in the thread named "Does the SCM SCR3320 work with
GnuPG?", I wrote that gnupg with Debian version 1.4.9-4 cannot use an OpenPGP v1
card in the SCT3511 reader. I've installed Debian version 1.4.10-1 from
unstable, and it seems there is no change in the situation.

I did however discover something rather important. Just once in a while,
decryption with the card will actually work!

Always when the decryption fails, it is because the card sends its ATR instead
of the requested data.

It seems that most of the time decryption fails when the PC tries to read the
plaintext from the card after the card has reported succes for the issued PSO:
DECIPHER command.

Somewhat less frequent the card will send its ATR after the VERIFY CHV1 command.

And even less frequent it just works.

The mailing list complained about the length of my message, so I put the debug
logs on the web.

This is the debug log for when decryption is succesful:

This is the debug log for when it fails after PSO: DECIPHER:

This is the debug log for when it fails after VERIFY CHV1:

Oh, BTW, I changed the PIN on the test card to 123456 instead of the longer
12345678 used before.

Thanks for your time,



I'm using the GNU Privacy Guard (GnuPG) in combination with Enigmail.
You can send me encrypted mail if you want some privacy.
My key is available at

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