[115545] in cryptography@c2.net mail archive
Re: kit to prevent computers from losing power during seizure.
daemon@ATHENA.MIT.EDU (Peter Gutmann)
Thu Feb 21 12:07:46 2008
From: pgut001@cs.auckland.ac.nz (Peter Gutmann)
To: cryptography@metzdowd.com, perry@piermont.com
In-Reply-To: <87zlu283jm.fsf@snark.cb.piermont.com>
Date: Sat, 16 Feb 2008 17:26:36 +1300
"Perry E. Metzger" <perry@piermont.com> writes:
>It appears that disk encryption techniques are spawning technical responses.
>This gadget lets law enforcement take a computer without ever turning off the
>power.
For those who don't want to plough through the docs, it looks like a static
transfer switch that requires you to take a tap from a mains line and feed it
to a UPS. The "tap" relies on either having the PC on a power strip or
stripping the mains flex and attaching jumpers. So the setup before is:
Mains -------------------+------ PC
|
UPS ------- STS -------+
When you unplug the resulting setup from the wall, the HotPlug device detects
the voltage loss (in other words it contains a portion of a UPS switchover
circuit, the static transfer switch, which is just some SCRs operating as a
zero-crossing switch and a controller IC) and switches over to the UPS:
+------ PC
|
UPS ------- STS -------+
and you can remove the PC.
I was going to suggest that given the usual LE-targeted device pricing (five
figures and up) it'd probably be cheaper to buy a commercial STS, but at only
$500 it's quite reasonably priced.
>Countermeasures are, of course, quite possible.
And successively more Rube-Goldberg :-).
Peter.
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