Relativity Used to Devise New Form of Crypt

Cebert writes "CNN.com posted an article about using relativity to create a new form of encryption. The new encryption allows an individual to make a prediction with a guaranteed date stamp that only they can reveal. " Hmmm...quantum predictions. Yeah, I guess that's hard to crack.

Comments

Here are a few more details

[VanL]

The article is a little short on facts. Here are a few more details:

ABSTRACT:
Unconditionally Secure Bit Commitment

Adrian Kent
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, United Kingdom

(Received 13 July 1998)

We describe a new classical bit commitment protocol based on cryptographic constraints imposed by special relativity. The protocol is unconditionally secure against classical or quantum attacks. It evades the no-go results of Mayers, Lo, and Chau by requiring from Alice a sequence of communications, including a postrevelation verification, each of which is guaranteed to be independent of its predecessor. ©1999 The American Physical Society
Here are copies of his article in pdf and in gzipped PS.

I

Try this instead

[bholzm1]

Here's the preprint in ps from LANL, instead; only institutional subscribers have access to the PRL online article.

Protocol to secure REAL TIME communication only

[yabHuj]

I read from the article (e.g. the Postscript version of the original article on LANL), that this protocol can only be used to secure real time communications only.

The protocol cannot be used for email or file encryption. With this protocol one can only make sure, that the line you are currently using is secure.

As timing is a critical of the security mechanism, standard internet with nondeterministic transmission times does not qualify for this protocol.

Nonetheless an interesting article (and as "smooth" to read as any other scientific article).

#define rant_mode
A classic case of hearsay (=RTFM failure) and media hype.
#undef rant_mode

Watch out for those wormholes

[foobarbazquux]

Admittedly, I was a tad sceptical about all this but it does seem to be right. For real-time communications only, of course.

A caveat: If there exists a wormhole between A and B such that the time taken from A to B is 'subverted' to be smaller than expected, the whole system breaks down.

So in effect, you have to check that the local space between A and B is Minkowski-like before communicating. Or just trust!

Re:Is this for real?

[MindStalker]

Umm, maby its just me, but I didn't think we figured out faster than light messaging yet between planets, but then again, maby I'm wrong.

Login difficulty

[The Wookie]

Unfortunately, this scheme presents a problem, because when using quantum encryption, it is not possible to know both your user name and password at the same time.

Not to mention the fact that someone keeps killing /bin/cat.

Don't look!

[Kaa]

> Not to mention the fact that someone keeps killing /bin/cat.

Actually, I'm not sure whether mine's dead or alive. I'd better go check...

Don't go and check! Until you look your /bin/cat is in superimposition of states and so works OK. As soon as you check, the wave function collapses and you have a chance of getting a dead /bin/cat!

Disclaimer: this assumes a Copenhagen interpretation. If you like multiple universes better, you can check your /bin/cat without any problems -- nothing more serious than forking of the whole universe is likely to occur.

Kaa