[Cryptech Tech] Alpha board block diagram v0.001

[Peter Gutmann]

=?UTF-8?B?0J/QsNCy0LXQuyDQqNCw0YLQvtCy?= <meisterpaul1 at yandex.ru> writes:

>My feedback is below.
>
>1. Power Supply

While we're on the subject of power supplies: You cannot have too much power
conditioning on the HSM's power input, both to prevent stuff coming in (glitch
attacks) and to prevent anything getting out (DPA and the like).  About 15
years ago when the first DPA attacks were being published, one particular
product was totally immune to them.  I talked to one of their hardware guys
and his comment was "we just used good engineering practice to make sure the
power quality was good, the DPA (and everything else) resistance came for
free".

I don't know too much about power supply engineering, but lots of filtering, 
over- and under-voltage protection (perhaps a DC/DC converter so no matter 
what rubbish comes in, you get 12DVC out, or more likely 3.3VDC or similar 
out), and then more filtering on the other side as well?  You also need to 
figure out a schedule for glitches, say < 10ms = ride it out, >= 10 ms then 
the electronics can run for another 100ms from stored power (to do a clean 
shutdown) but you then have to do a cold restart rather than trying to 
continue.

Peter.