Is Quantum Encryption Perfect, or Just Really Good?


Nobody doubts that quantum encryption is gaining momentum. The question among researchers is whether it is effective -- or perfect.


Quantum encryption harnesses one of the strangest branches of science to help secure networks. According to this CNET News story, the world's largest network using this type of security has been unveiled in Vienna. The project is overseen by the a European Union group called SECOQC, which translates to Development of a Global Network for Security Communication Based on Quantum Cryptography. The network is run by the University of Vienna and was developed over four years by 41 organizations in 12 countries.


In fiber transmissions, photons representing data are sent between points. The idea behind quantum encryption is that if photons are intercepted during transmission and an attempt is made to read them, their polarity will shift and a detectable spike in error rate will follow. TechTree has a good description of what happens. The writer smartly avoids dealing directly with quantum mechanics, an area that is impossible for mortals to understand.


There may be a fly in the ointment, however. This piece in New Scientist, which also offers a good explanation of how quantum encryption works, suggests that its security might be overestimated. The piece details an approach suggested by Vadim Makarov, a postdoctoral researcher at the Norwegian University of Science and Technology in Trondheim. Essentially, Makarov suggests that a flash of laser light can be used to manipulate the receiving device into reporting that the photons had not been tampered with.


This commentary by Larence Walsh discusses quantum encryption in the context of larger security issues. It described the Data Encryption Standard (DES) and Triple DES and the Advanced Encryption Standard (AES). Walsh says that quantum encryption is expensive, difficult to manage and has limited applications. Moreover, he says that in the final analysis, one piece of security -- be it quantum encryption, DES, Triple DES or AES -- is only one part of an overall security effort. The real key to security is more broadly managing risks and reducing the organizations' threat profile. This includes but takes more than finding a great way to encrypt data.


Totally secure or not, quantum encryption is finding at least some users. Durban, South Africa, which is called the SmartCity of Africa, is in the process creating a network that relies on quantum encryption-based security. The University of KwaZulu-Natal's Centre for Quantum Technology is deploying the network over the eThekwini Municipality fiber infrastructure, according to this piece. The project, labeled the QuantumCity project, is being conducted in conjunction with idQuantique and the Senetas Corp.


There are several important questions that quantum encryption will face during the next year. The first is whether it is perfect, or just really good. The follow up is whether -- perfect or not -- it is flexible enough for widespread use.