[Nottingham] Can't remember the term for a cryptographic technique...

[Danny King]

Bingo! Thanks Roger! Plausible deniability was the key phrase I was
trying to remember. I remember having read the wikipedia article at
http://en.wikipedia.org/wiki/Deniable_encryption and finding it very
interesting indeed.

Thanks for the heads up Martin about not feeling too comfortable with
encrypted filesystems.

For anyone interested, TrueCrypt can apparently encrypt windows, mac &
linux filesystems and has support for plausible deniability. Maybe one
day I'll play around with it and do a talk.

2008/5/28 Roger Light <roger at atchoo.org>:
> On Wed, May 28, 2008 at 09:44:34AM +0100, Joshua Lock wrote:
>> On Wed, May 28, 2008 at 9:25 AM, Danny King <dannyking at gmail.com> wrote:
>> > Hi all,
>> >
>> > A bit off topic so I apologise in advance:
>> >
>> > At the last meeting I was having a conversation with a few people and
>> > we briefly touched on cryptography, specifically a certain area of it.
>> > I can't for the life of me remember the term used to describe the
>> > practice of encrypting a message so that two separate keys provide
>> > different plaintexts when used on the same cyphertext i.e.:
>> >
>> > Alice creates a cyphertext from her secret message and gives Bob key1
>> > and Fred key2. Bob uses key1 to decode the true message whilst Fred
>> > uses key2 on the same cyphertext to decode a different but still
>> > conceivable message.
>> >
>> > Can anyone help me to remember the name of this practice? I've been
>> > googling and wikipeding for an hour with no success!
>>
>> Hmm, not sure. Sounds a bit like it could be Steganography? What with
>> the hidden messages and all.
>
> Close, but no cigar. This sounds very similar to burglar alarm codes
> where one code deactivates the alarm properly and another code
> deactivates the alarm but alerts the police (or other agency) that
> the code has been entered against the will of the person entering.
>
> In the case of encryption, it gives plausible deniability.
>
> So I'd try searching for "duress encryption" or something similar.
> Given the powers of the government to require you disclose
> encryption keys (iirc) based on RIPA, it might be worth including
> that as well.
>
> Cheers,
>
> Roger
>
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