[Cryptography] high-school crypto project

[Andreas Gunnarsson]

On Wed, May 07, 2014 at 12:16:15PM -0700, John Denker wrote:
> Secondly, quantum cryptography is the most-challenging area of
> a challenging subject.  It requires an understanding of physics
> waaaay beyond anything that is normally covered in high school.

That depends... I'd say that it should not be much more difficult to
peek into some aspects of it and play around with simulated quantum
circuits without a deep understanding of quantum mechanics than it is to
understand electronics and microprocessors without Maxwell's equations.
Perhaps it could be possible to simulate a quantum key distribution
system with something like LanQ (http://lanq.sourceforge.net/) ?

Of course, since quantum computing is still only a research field, it
may be difficult to find literature and information that is not highly
technical, but in principle it does not have to be *too* hard.

> Quantum cryptography would make more sense as a graduate thesis
> of above-average difficulty, rather than as a high-school project.

I believe that "quantum cryptography" is often used to mean quantum key
distribution which you also mentioned. My impression is that it makes
some strange assumptions about the threat model where it guards against
some hypothetical weaknesses in classical cryptography while it ignores
some other threats without justifying why the other threats are not
important. Not to mention that there are engineering problems that could
make the system insecure. But I haven't kept up to date so maybe there
has been some interesting development lately. I don't know whether or
not it would be a suitable high-school project to examine what threats
it counters and what it doesn't.

> In any case, the effect on current crypto standards is nil.

I agree. A common misconception seems to be that when we have big enough
quantum computers we will be able to crack any current crypto
algorithms. My understanding is that there is no evidence that quantum
computing will help breaking symmetric crypto. In some sense a quantum
computer can "try all keys at the same time", but there is no way to
filter out the answer you are interested in. In some problems it may be
possible to exploit the structure of the problem, and that's how Shor's
algorithm can factor large numbers efficiently (but we don't yet have or
even know if it is possible to build large enough quantum computers).

> As an almost-reasonable compromise, one might consider writing
> a paper debunking the claims on this page:
>   http://digitaldisruption.com/4-real-world-uses-quantum-cryptography
> perhaps by showing that each of the four applications could be
> handled more cheaply /and better/ using classical non-quantum 
> crypto.

Yes, there are many inflated claims about how quantum-xyz improves or
breaks cryptography, and they could need some scrutinizing.

Andreas