[Cryptography] Rubber-hose resistance?

[Patrick Chkoreff]

Jerry Leichter wrote on 12/21/2017 05:21 PM:
...
> For the rest of us, probably the best thing to do is to encrypt
> everything before it goes to the device.  Destroy the key, and the
> device is logically erased instantly.  (Both iPhones and some Android
> devices actually do this.)

Right.

> Of course you run into the "turtles all the way down" problem:  If
> you store the key on the device itself ... how do you erase it when
> you can't control what gets written where?

Right.  I can tediously ponder any number of software counter-measures,
but they're all vulnerable.

>> I suppose now it's safest just to shred the SSD physically before
>> you return from the trip.  Either return with no hard drive or
>> install a spare.

> While the information may be *present* on the drive, getting it out
> requires specialized hardware and techniques.  How valuable is this
> information?  How serious an attack are you concerned about having to
> survive? -- Jerry

My own threat model is not terribly demanding.  I mostly just want to
protect GPG and SSH private keys.

I think you have to physically destroy the device.  It's the only way to
be sure.  Carry only a disposable device, as Nico and Jeremy have
discussed, such as a Raspberry PI and SD card.  I think you can just
destroy the SD card, as I suspect no traces of information will remain
on the PI itself, discounting 4 degree Kelvin attacks on RAM.


-- Patrick