From: Brett Paatsch (paatschb@optusnet.com.au)
Date: Sat Jun 21 2003 - 15:55:55 MDT
Robert writes:
> On Sun, 22 Jun 2003, Brett Paatsch wrote:
>
> > I'm no encryption expert but since reading Simon Singh's
> > The Code Book back in 1999 I've had the impression that
> > there is a race on between the developers of quantum
> > computers that could crack existing codes and the development
> > of quantum encryption which could produce uncrackable
> > codes even given quantum computers.
>
> [snip]
>
> > http://www.commsdesign.com/news/tech_beat/OEG20021111S0036
>
> I'm not sure whether they are talking about quantum encryption
> or quantum entanglement.
Sorry I put it badly (saying encryption instead of cryptography) let me
quote a bit from Simon Singh.
"Quantum cryptography is a system that ensures the security
of the message by making it hard for Eve (the snooper) to
read accurately a communication between Alice and Bob.
Furthermore, if Eve tries to evesdrop, then Alice and Bob
will be able to detect her presence. Quantum cryptography
therefore allows Alice and Bob to exchange and agree on
a one time pad in acomplete privacy, and thereafter they can
use this as a key to encrypt a message.
(Singh then goes on to outline a five step procedure).
1) Alice sends bob a series of photons and Bob measures
them.
2) Alice tells Bob on which occassions he measured them in
the correct way. (Although Alice is telling Bob when he made
the correct measurement, she is not telling him what the correct
result should have been, so this conversation can be tapped
without any risk to security.
3) Alice and Bob discard the measurements that Bob made
incorrectly, and concentrate on those measurements he made
correctly in order to create an identical pair of one-time pads.
4) Alice and Bob check the integrity of their one time pads
by testing a few of the digits.
5) If the verification procedure is satisfactory, they can use
the one-time pad to encrypt a message; if the verification
reveals errors, they know that the photons were tapped
by Eve, and they need to start all over again "
So my question is if this technology could be reduced to
laptop price affordability would people rather have quantum
cryptograpy widely available or not? It would be uncrackable
by quantum computers.
> I believe these are entirely two
> different things. With entanglement you simply get to
> detect whether or not someone has read the message.
> I've got no idea what quantum encryption is. Quantum
> decryption, applied to normally encrypted messages allows
> you to do things like factor very large numbers extremely
> quickly allowing one to crack the codes on which most
> encryption schemes are currently based.
>
> If someone else knows more they should comment because I'm
> in way over my head here.
>
> Robert
>
>
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