Re: A New Cryptography Uses The Quirks of Photon Streams

[InfoSec News <isn () c4i org>]

Forwarded from: Nikolay Sturm <sturm () sec informatik tu-darmstadt de>

* InfoSec News [2002-11-04]:
> With the system, keys to the code are transmitted as a stream of
> photons, sent over a fiber optic cable. Because of the properties of
> quantum physics, the mere act of observing the transmission would
> alter the photons, rendering their information useless to any
> eavesdroppers.

This is not true in general, only when single photons are used for
communication. In reality people use weak laser pulses, which have a
certain degree of pulses with two or more photons. These permit
attacks.

> carefully controlled. But outside researchers say that quantum
> cryptography does make possible electronic conversations that would
> be immune to eavesdropping.

Not really, often enough you can eavesdrop other channels like the
keyboard or monitor or whatever.

> Research in quantum cryptography goes back into the 1980's. But
> MagiQ (pronounced as magic) and a Swiss competitor, ID Quantique,
> are the first to attempt to develop commercial systems based on the
> technology. ID Quantique's system has not yet reached the market.

This is plain wrong. ID Quantique sells their system for over 6 month
now. At the last Cebit in Hannover, Germany, they sold it for 100 000
Euro, AFAIR.

bye,

Nikolay

-- 
OpenPGP: 0x5C0878D2 - BB55 EDCF A1F6 8057 B953  4C66 EFBD BA73 5C08 78D2



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