MRAM, persistence of memory

Sampo Syreeni decoy at
Tue Jul 15 11:33:50 PDT 2003

On 2003-07-15, Thomas Shaddack uttered:

>Take a relay and connect it to a door switch.

Precisely. It's not just about manual shutdown, but all surprise
shutdowns. Also, I'm afraid of the possibility that simply switching the
power off might not do the trick -- we don't care about how dirty the
system state will become short of dataloss outside the current working
set, but we do need to be sure all crypto and plaintext I/O relevant state
is properly purged from memory and peripherals. There are plenty of
examples like printer buffers, random pools, already keyed smartcards,
anything you're currently showing on-screen (I wouldn't be surprised if
that could be read after sustained powerdown), any battery backed memory,
off-the-shelf peripherals which do not admit crypto, and so on. Probably
we'd also want to make the machine as dead as possible, shutting down any
remote power-on features, network connections (otherwise retries might go
on for a fair while), open phone lines, whathaveyou.

That's why we might need software, and not just the power switch. I can
also imagine situations where we'd want to be able to perform manual
shutdowns remotely.
Sampo Syreeni, aka decoy - mailto:decoy at, tel:+358-50-5756111
student/math+cs/helsinki university,
openpgp: 050985C2/025E D175 ABE5 027C 9494 EEB0 E090 8BA9 0509 85C2

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