[Cryptech Tech] Alpha board BOM and PCB design requirements

[Bernd Paysan]

Am Sonntag, 15. März 2015, 20:32:11 schrieb Benedikt Stockebrand:
> Hi folks,
> 
> Randy Bush <randy at psg.com> writes:
> > i'm with basil, c4
> 
> well, when liquid nitrogen enters the equation, C4 might actually be
> ill-suited; if I remember correctly it needs a combination of heat and
> shock to ignite...
> 
> Maybe we should actually opt for thermite instead; it's non-toxic, less
> noisy and easier to prepare ourselves:-)

And thermite is "officially" recommended for destroying data :-):

https://www.youtube.com/watch?v=k-ckechIqW0

http://hackaday.com/2008/09/16/how-to-thermite-based-hard-drive-anti-forensic-destruction/

The pro side is that *all* you need is readily available: aluminium powder, 
Fe3O4 powder, sparklers (magnesium based fireworks), flower pots.

For ignition, you need an ultracap, and a copper wire, wrapped around the 
sparkler.  You short the cap through the copper wire, it will heat up far 
enough to ignite the sparkler, which then ignites the thermite.  Make sure the 
thermite "bomb" can ignite itself even when completely disconnected.  Put the 
entire HSM into a bigger ceramics or concrete pot so that when it ignites, it 
doesn't cause further harm.  As long as it melts down itself, everything is 
fine.

The way to keep Bruce Willis from disarming the bomb is to require a permanent 
low-ohmic connection on all ingoing wires (i.e. both the red and green wire 
must be low-ohmic to supply).  If any of them goes high-Z, kaboom.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/
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