[14282] in cryptography@c2.net mail archive
Re: Can Eve repeat?
daemon@ATHENA.MIT.EDU (Ivan Krstic)
Thu Sep 25 22:54:06 2003
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To: Greg Troxel <gdt@ir.bbn.com>, iang@systemics.com
From: Ivan Krstic <ccikrs1@cranbrook.edu>
Date: Thu, 25 Sep 2003 12:35:46 -0400
In-Reply-To: <rmi65ji74b2.fsf@fnord.ir.bbn.com>
On 24 Sep 2003 08:34:57 -0400, Greg Troxel <gdt@ir.bbn.com> wrote:
[snip]
> In Quantum Cryptography, Eve is allowed to not only observe, but also
> transmit (in the quantum world observing modifies state, so the notion
> of read only doesn't make sense). Also, Eve is typically accorded
> unlimited computational power.
[snip]
The idea that observing modifies state is something to be approached with
caution. Read-only does make sense in quantum world; implementations of
early theoretical work by Elitzur and Vaidman achieved roughly 50% success
on interaction-free measurements. Later work, relying on the quantum Zeno
effect, raised the success rate significantly: "Preliminary results from
new experiments at Los Alamos National Laboratory have demonstrated that
up to 70 percent of measurements could be interaction-free. We soon hope
to increase that figure to 85 percent."
The quote comes from a article by Kwiat, Weinfurter and Zeilinger
published in SciAm, November 1996 -- if they were getting success rates
like these back then, I wonder what the current status is.
The article is well worth a read. There's a copy online at:
http://www.fortunecity.com/emachines/e11/86/seedark.html
Best regards,
Ivan Krstic
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