[Cryptography] French credit card has time-varying PIN

[Tom Mitchell]

On Tue, Oct 4, 2016 at 10:51 PM, Ron Garret <ron at flownet.com> wrote:

>
> On Oct 4, 2016, at 8:58 PM, Peter Gutmann <pgut001 at cs.auckland.ac.nz>
> wrote:
>
> > In addition there's the outrunning-the-bear issue,
>
 ......

> Well, I must confess, that is a very good point.


One such card is not too interesting but a common wallet full
would constitute a possible random seed generator.
Drop  four or five  cards on the table.  Read the current numbers
from the dropped set, add subtract mod multiply divide to the correct value
limit
and insert 'entropy' in a PRNG.

I can see value in ID documents and even employee system access
devices.  Three years for an credit card size device to generate a
sufficiently
stable stream of bits to synchronize with a system home is interesting.
Combine something you know with something you have (like this) is
an interesting thing.





-- 
  T o m    M i t c h e l l
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