[10832] in cryptography@c2.net mail archive
Re: Commercial quantum crypto product - news article
daemon@ATHENA.MIT.EDU (Hannes R. Boehm)
Fri May 31 19:19:38 2002
Date: Sat, 1 Jun 2002 00:32:15 +0200
From: "Hannes R. Boehm" <hannes@boehm.org>
To: cryptography@wasabisystems.com
In-Reply-To: <2F1A38DC0413D311A7310090273AD527042023F8@dthrexch01>
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On Fri, May 31, 2002 at 08:57:46AM -0600, Kossmann, Bill wrote:
> Anybody familiar with this product?
Yes - a little.
As far as I know, they use phase coding of weak pulses
(meaning that a puls contains an average of less than a photon).
The average number of photons per puls depends on the probability=20
you want to have that a puls carries more than one photon (as determined by
statistic calculations).
Phase coding works with an interferometer (actually it is a double interfer=
ometer)
setup. Alice and Bob are on different arms of the (Mach-Zehnder) Interferom=
eter and=20
are both aplying phase shifts on the wave function of the photon (randomly).
IMHO the weak puls method is not as beautiful as a
entangled photon implementation, since there is still the possibility
that more than one photon carries the information (even though, statistics
teaches us that this probability can be made abitarly small)
And: there have to be random number generators on Alice and Bobs side - whe=
reas with=20
entangled photons, the key is created simultaniously on both sides ("it nev=
er passes the wire").
But: it is available now, as far as I know there is no comercial systems wi=
th entangled=20
photons to date - even though it has been demonstrated in the lab. I think =
that=20
soon other systems will be available to choose from - lets wait and see.
What I can tell about the company "idquantique.com" is, that it was
founded as an offspring of the university of Geneva. Somehow Nicolas Gisin
is involved, who is one of THE experts on the field of Quantum Cryptography.
(I dont know wether it belongs to the university or not)
Hannes
=20
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Hannes R. Boehm
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Institute of Experimental Physics
University of Vienna=20
Boltzmanngasse 5=20
1090 Wien
Austria
web : http://www.quantum.univie.ac.at/
email: hannes.boehm@exp.univie.ac.at
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email: hannes@boehm.org=20
web : http://hannes.boehm.org
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