[cryptography] US Appeals Court upholds right not to decrypt a drive

Marsh Ray marsh at extendedsubset.com
Sun Feb 26 14:09:31 EST 2012

On 02/26/2012 11:35 AM, Jon Callas wrote:
> On Feb 25, 2012, at 3:18 PM, Kevin W. Wall wrote:
>> On Sat, Feb 25, 2012 at 2:50 AM, Jon Callas<jon at callas.org>
>> wrote:
>>> I asked them about the case where someone has TrueCrypt but
>>> doesn't have a hidden volume, what would happen to someone
>>> doesn't have one? Their response was, "Why would you do a dumb
>>> thing like that? The whole point of TrueCrypt is to have a hidden
>>> volume, and I suppose if you don't have one, you'll be sitting in
>>> a room by yourself for a long time. We're not *stupid*."
>> That's good to know then. I never had anything *that* secret to
>> protect, so never bothered to create a hidden volume. I just wanted
>> a good, cheap encrypted volume solution where I could keep my tax
>> records and other sensitive personal info. And if law enforcement
>> ever requested the password for that, I wouldn't hesitate to hand
>> it over if they had the proper subpoena / court order. But I'd be
>> SOL when then went looking for a second hidden volume simply
>> because one doesn't exist. Guess if I ever go out of the country
>> with my laptop, I'd just better securely wipe that partion.
> Or just put something in it that you can show.

So everyone who now has a hidden 2nd Truecrypt partition with 
incriminating things in it needs to make it their hidden 3rd partition 
and in the hidden 2nd partition instead store things which are merely 

Except that as it is stipulated that the captors are "not stupid", we 
must assume they are perfectly rational actors who will have worked out 
this strategy too.

I bet there could be an interesting paper with a game-theoretic analysis 
of this "traveler's dilemma". Maybe it's been written?

On each round, a traveler with hidden encrypted volumes which he prefers 
not to disclose must cross a border in which he passes through a "civil 
rights-free zone", placing himself under the control of a jailer. At the 
beginning of each round, the traveler selects the number of hidden 
volumes he will carry from some set of predefined 4-tuples: (cost/payoff 
to traveler if disclosed/not disclosed, cost/payoff to jailer if not 

The round proceeds in turns. On each turn, the jailer may elect to pay a 
cost to imprison the traveler for another turn, or let the traveler go 
free. On each turn, the traveler selects to disclose some (or none) of 
any undisclosed volumes he has remaining. The round ends when the 
traveler goes free.

What is the optimal strategy for the jailer? For the traveler?

How does it make sense to set up the initial costs?

- Marsh

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