QC Hype Watch: Quantum cryptography gets practical

Tyler Durden camera_lumina at hotmail.com
Sat Oct 2 17:50:03 PDT 2004


Yes, I am indeed a little suspicious. Clearly, this "quantum repeater" can't 
be doing an O/E, or no amount of hype will budge this product an inch.

Quantum Crypto utilizes pairs of correlated photons, so we can't be talking 
about an optical amplifer.

So since I've been away from the literature for a while, is there a device 
that can repair a deteriorating, about-to-be-collapsed superposition state? 
I can't see how this could occur without the requirement of acting on the 
other (correlated) photon either, and if that photon is physically removed 
from the first, then forget about it. (Though theoretically I think I can 
conceive of the possibility of two "correlated quantum repeaters" exchanging 
'information' (including gating) about the photon pair they are collectively 
handling*, but no way that can be useful commerically.)

*: This isn't quite as farfetched as it seems: Even 5 to 10 years ago it was 
shown that there can be quantum Forward Error Correction, and simple devices 
were demonstrated in the laboratory.

-TD




>From: Bill Stewart <bill.stewart at pobox.com>
>To: "Tyler Durden" <camera_lumina at hotmail.com>
>CC: cypherpunks at al-qaeda.net, rah at shipwright.com
>Subject: RE: QC Hype Watch: Quantum cryptography gets practical
>Date: Fri, 01 Oct 2004 11:59:40 -0700
>
>At 05:12 PM 9/30/2004, Tyler Durden wrote:
>
>>What's a "quantum repeater" in this context?
>
>It's also known as a "wiretap insertion point"...
>
> > As for "Hype Watch", I tend to agree, but I also believe that Gelfond
> > (who I spoke to last year) actually does have a 'viable' system.
> > Commerically viable is another thing entirely, however.
>
>"Practical" implies that there's a crossover point between
>cost and benefit and that implementation is on the "benefit" side.
>
>Implementation may now be possible, and the costs may be lower
>than their previous infinite value, but the main benefits I see are
>public relations hype to impress the rubes and protect against
>zero-day exploits against Diffie-Hellman or Cisco IOS.
>But you could protect against the Cisco exploits just as easily
>with a conventional-key encryption hardware box,
>and you wouldn't need contiguous fiber.

_________________________________________________________________
Is your PC infected? Get a FREE online computer virus scan from McAfee. 
Security. http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963





More information about the cypherpunks-legacy mailing list