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By Andrew Zimmerman Jones, About.com Guide to Physics

A Case for Quantum Cryptography

Sunday August 31, 2008
One of the major concerns regarding the creation of quantum computers is that these devices would be so advanced that they would be able to crack current computer cryptography systems. Security in computer systems is based upon long numbers where are multiples of two primes. For a computer to break into one of these encryptions, they would have to figure out the prime factor of the number which would essentially take longer than the length of the universe (in theory, at least) ... but for a quantum computer could take only hours or days.

To counter this concern, some have proposed quantum cryptography, by which particles use quantum entanglement to make sure that information passes between them in a completely secure manner. Though there has been some success in transmitting this information long distances (see Quantum Encryption Through Space), these systems still have not proven effective in transmitting the encryption through fiber optic cable systems over distances longer than a few kilometers.

A new form of quantum encryption experiment uses multiple clouds of rhubidium atoms which become sort of entangled chain and can be used to transmit the entanglement the full distance required for the encryption. According to the experimenters, this system would require a cloud about every 10 kilometers, but in theory should be able to be used for pretty much any distance required.

Though this particular experiment is pretty much a "proof of principle" experiment, it comes at a time when technology companies are looking to exploit quantum encryption in a realm of growing information insecurity. This technology is on the brink of going commercial on a large scale and every movement in that direction is worthy of note.

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Comments

September 2, 2008 at 10:01 pm
(1) Some guy says:

Errors:
“Security in computer systems is based upon long numbers where are multiples of two primes”
Security in computer system is based upon the assumption that given an integer which is the product of two primes, it is computationally infeasible to determine these primes.

“particles use quantum entanglement to make sure that information passes between them in a completely secure manner”
The information that passes through them is not secure. However, we may detect an eavesdropper. The technique is used to share a key, not to encrypt information.

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