“Hardware problem” with OpenPGP smart card

[Werner Koch]

On Mon,  7 Dec 2020 23:37, Nicolas Boullis said:

> Hence, I think my card is really dead.

yeah :-(

> I see that the card includes a signature counter (which reads 89), hence 
> I understand the card has to write the EEPROM (to update the counter) 

Yes, this one reason to write to the EEPROM.  However, this is a way too
low number for a failure.  A few years ago we had a similar report and
the Zeitcontrol folks did some testing.  A 100000 operations were not a
problem at all.  From my understanding the EEPROM of the chip used by
Zeitcontrol allows for much more r/w cycles than what you usually get
from an average Atmel or so microcontroller.  Anyway, my STM32 based
Gnuk token did about 8000 signing operaion with the first key.

> between 1,000 and 10,000 authentications with that card. I think it 
> might be sufficient to wear an EEPROM.

Nope.  

> Also, the card reports 2 tries left for the PIN code, which means that 
> my last try to unlock the unlock the pin was a failure. Did the card 
> somehow fail updating the retry counter? (Either when I typed the wrong 

It failed.  Smartcards handle verification by first decrementing the
retry counter, running the verify, and on success incrementing the retry
counter.  This is so that a power glitch can't be used to trick out the
retry counter.  This method explains why you see 2.

> If there’s anything I can do to investigate that failure, please tell 
> me.

The card should not allow you to investigate things even after a failure.


Shalom-Salam,

   Werner

-- 
Die Gedanken sind frei.  Ausnahmen regelt ein Bundesgesetz.
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