[isapros] Re: OT: College Research Paper (Quantum Cryptography)
- From: "Gerald G. Young" <g.young@xxxxxxxx>
- To: <isapros@xxxxxxxxxxxxx>
- Date: Mon, 2 Oct 2006 14:37:07 -0400
True, in quantum communication they use photons but it is linked to
values presented by qubits. The qubit - or quantum bit, for those not
familiar with the term - is based on quantum mechanics, as I understand
it, and it is the decoherence of the quantum state that destroys the
result once it is read. Still, the BB48 and QKD protocols provide some
error handling (not sure how at all - too deep for paper) but these
protocols allow for either side to determine that a transmission has
been listened to because of a public channel employed by the protocols
(they compare private results against public results).
But that's pretty much along the line of questioning I wished to ask:
How is quantum information communicated between two parties when
intended or unintended interference (which disrupts the quantum states)
occurs? While this might prevent listening to the transmission and
discerning the content and meaning of the message, what would prevent
the message from being jammed (DOS against traffic)?
With regards to quantum cryptography, where quantum computing is used to
decipher ciphers, how much faster is it than classical computing? I
understand that where a 3-bit register can only be one of eight possible
values at any given time, a 3-qubit register can be all (they call this
superposition, I believe). I also understand logically that with a
classical computer it will take on average (n + 1)/2 guesses (where n =
number of possible answers, usually 2 ^ number of bits) to determine a
cipher but with a quantum computer that changes (proportionally) to the
square root of n for the number of guesses.
So, for a 64-bit key, on a classical computer it would take
9,223,372,036,854,775,809 guesses, which would take... how long? I know
it's a long time, but how do you determine the time? On a quantum
computer, though, the same 64-bit key would take only 4,294,967,296
guesses. Again, how might you determine time? And how does
superposition affect the processing? In a classical system you can only
compare 1 value against a single value in the n-bit register during a
single operation. However, in a quantum computer you can compare that 1
value against all of the possible values in the n-qubit register during
a single operation.
I could also be totally annihilating the terminology here. My apologies
if I am. :-) But, this is the reason I'm asking. Everything seems to
talk about quantum whatever as everything being based in some way on
quantum mechanics.
Cordially yours,
Jerry G. Young II
Applications Engineer, Platform Engineering
Enterprise Hosting
NTT America, an NTT Communications Company
22451 Shaw Rd.
Sterling, VA 20166
Office: 571-434-1319
Fax: 703-333-6749
Email: g.young@xxxxxxxx
________________________________
From: isapros-bounce@xxxxxxxxxxxxx [mailto:isapros-bounce@xxxxxxxxxxxxx]
On Behalf Of Thor (Hammer of God)
Sent: Monday, October 02, 2006 1:14 PM
To: isapros@xxxxxxxxxxxxx
Subject: [isapros] Re: OT: College Research Paper (Quantum Cryptography)
As I understand it, quantum cryptography not just has the "potential" of
determining if the traffic is being sniffed, but it actually "breaks"
when intercepted in any way. It follows the same theory of measuring
any quantum particle- any means we current have to use to measure the
speed or direction of a quantum particle (like bounding another particle
off of it and observing that particle's behavior) actually changes the
speed and direction of the quantum particle one is trying to measure in
the first place. Same with the encryption. Any process used (other
than the end point reception) to intercept the particles would end up
changing them, thus breaking the whole thing.
But that is for true "quantum cryptography" not these guys using photons
and calling it "quantum." Bruce Schneier talks about it briefly in
Applied Cryptography, which is a great book to curl up with on a Sunday
afternoon. ;)
hth
t
On 10/2/06 6:55 AM, "Gerald G. Young" <g.young@xxxxxxxx> spoketh to all:
This is way off topic here but given the security background of most on
the list, I thought I'd throw this out.
I'm doing a short (thank goodness!) research paper for a college IT
course. I chose to write about the security ramifications of quantum
computing. In the paper I need a minimum of 4 references with at least
1 reference from 3 different types (web, book, magazine, interview,
etc.). I have two different types now and an abundance of references I
can use. I'm looking for a third of the interview type.
I am just looking for someone who might be in the know with regards to
this technology and the potential affects it may have on IT security as
we know it.
I'd like to specifically ask questions regarding the potential of
quantum cryptography being able to determine when someone is listening
in on traffic (that's kewl!).
If there's anyone out there who may be familiar with this topic, can you
please shoot me an email?
Cordially yours,
Jerry G. Young II
Applications Engineer, Platform Engineering
Enterprise Hosting
NTT America, an NTT Communications Company
22451 Shaw Rd.
Sterling, VA 20166
Office: 571-434-1319
Fax: 703-333-6749
Email: g.young@xxxxxxxx
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