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Swiss Scientists Prove Durability of Quantum Network, So what?

The main goal of the SwissQuantum network, installed in the Geneva metropolitan area in March 2009, was to validate the reliability and robustness of QKD in continuous operation in a network over a long time period in a field environment. Courtesy of SwissQuantum.

So, probably you’ve already heard–most probably not. The Institute of Physics and the New Journal of Physics recently released a paper on the long term performance of the SwissQuantumat CERN on field environment. And since I have taken the ambitious task of making all this technical stuff understandable to the average reader, I decided to try and write in less blah blah and more in the way that hopefully you’ll understand what this means for you.

If you still have no idea what cryptography is, congratulations for getting out of that cave you’ve been hiding in for most of written history. Consider this my welcome present. Simply put, cryptography is secret writing or obscure writing where the message is “hidden” in such a way that only the right person will be able to read it. It is centered around the idea of a “key” to “unlock” the message.

Decades ago, mathematicians introduced a new breakthrough in cryptography: one-way functions which lead to Public-key Cryptography. Today, everything that needs to keep your information secure uses a form of cryptography — from ATMs,  e-mails, social networks, your mobile to a lot of electronic devices. Now, this is all well and good and it kept the system secure for a while but the thing is, cracking it is not impossible, just improbable due to limits of computing power. At the time RSA was proposed, it would take a millennium to break a 192-bit encryption by brute force. In 2008, cryptanalysts proved that with the computing power then, it would take only eight months.

So what do we do? Well, for one thing, we can raise the key size. Today the industry standard is 192-bits and lots of crossed fingers. But this is a band aid solution.

And so the war between cryptographers and cryptanalysts is now on a critical phase. 2 decades ago, theoretical and experimental physicists joined the war equipped with quantum mechanics. With quantum computers, it promises cryptanalysts to be able to break today’s most powerful Public-key Encryptions. But what quantum mechanics breaks with one state (pun intended) it helps protect with another. With quantum cryptography, it promises provably secure encryptions and the power of one-time pads without the having to worry about key distribution problems.

Now, remember this, there is only one perfectly secure cryptosystem known: Vernam cipher or one-time pad. But there is a catch: a pad should never be reused. As long as the pads are unique and never reused no statistical analysis or pattern matching techniques can be applied by cryptanalysts. The fact that the pad can be used only once is the “one time” point of this cipher. So the biggest problem is, how do you send these “pads”/”keys” securely, over the network?

Well, folks, that’s what our friends at Switzerland had been working on for a year and a half. While the study on Quantum Key Distribution (which enables two parties to share a secret key before using that key to protect data they want to send over a network) started with Bennett and Bassard in the 1980s, this paper is one giant step into bringing Quantum Cryptography out of the labs and into the “fields”. Through a long term study, they have proven that “QKD has the maturity to be deployed in telecommunication networks. It has proven its reliability and robustness in a real-life environment outside of the laboratory.”

Of course, this doesn’t mean that telecommunication networks will begin using them anytime soon but it is a start in that direction. Apparently, there are some issues about external problems, such as power cuts and air conditioning problems. (Did you think you’re the only one? QKD layer hates it, too.) Also, QKD is not without faults because even if in theory this is a perfect system, physicists and engineers are working with less than perfect physical systems called “real-life”. And in real life there is always a margin of error. And that margin of error is what engineers exploited last year.

While quantum computing is still at its infancy and the most ideal equipments to provide the security parallel to that in theory exists only in the physicists’ mind, efforts at Europe and Los Alamos are still underway to strengthen implementations of Quantum Cryptography. The question is, will Quantum Cryptography implementations be a as unbreakable as promised by it’s theoretical security? 


About princess of antiquity

Abbi Cabanding is a member of the Security Bloggers Network and had been blogging on information security since 2006. She is also a member of the Association for Computing Machinery. She studied Computer Science and Fine Arts at the University of the Philippines - Diliman.



  1. Pingback: Swiss Scientists Prove Durability of Quantum Network, So what? « Would you buy it for a quarter? - December 7, 12:09 am

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