What is the method of realizing highly confidential encrypted communication made possible by a smart camera?

ByNokia Connect

"Encrypted communication" is widely used to secure secure Internet communication, among whichRandom number sequenceA string of numerical characters called (random number) plays an important role. In order to make it difficult to decrypt the encryption and improve secrecy, it is indispensable to raise the accuracy of the random number sequence. For that purpose, precise and expensive equipment has been required, but the research team at the University of Geneva By diverting the camera of a relatively inexpensive smartphone as it is,Quantum random number sequence"Can be generated.

[1405.0435] Quantum random number generation on a mobile phone
http://arxiv.org/abs/1405.0435

Quantum Random Number Generator Created Using Smartphone Camera - The Physics arXiv Blog - Medium
https://medium.com/the-physics-arxiv-blog/602f88552b64

I developed this methodUniversity of GenevaA research group of Bruno Sanguinetti who is advancing research on quantum optics and quantum communication.


The research team used what Nokia had been selling since 2011 "Nokia N9"It is a model with an 8 megapixel camera. This terminal is Linux based on OSMeeGoIt is also known as "first and last" model which adopted (Mego).


In order to improve the confidentiality of encrypted communication, it is necessary to generate a highly accurate random number sequence, but with this camera-based method, it is necessary to generate a sequence of "photons" We detect random numbers and generate random numbers. The light sensor mounted on the smartphone has advanced its performance and can detect the number of photons received, but first the light is emitted from the light source toward the camera, the result of the light sensor receiving the light It converts to digital and generates a random number. Since the phenomenon that such light is emitted is quantitative, it is impossible to predict the timing and amount, so it is possible to generate a highly accurate (high randomness) sequence of random numbers became.


Encryption of data is widely used to enhance secrecy of communication such as Internet communication, etc. In order to enhance the quality of encryption, the precision of the random number sequence used as the "key" at the time of encryption is important . A random number sequence is a character string which does not have a rule in the arrangement of the numbers contained in it, and it is said that it is almost impossible for others to generate a character string of exactly the same content. Therefore, it is possible to make restoration of encrypted data almost impossible for a third party who does not know the contents of "key".

However, as this random number sequence is generated by computers in many cases, there are circumstances in which it can not be said that it is a pure random number in a true sense. Even computers that do sophisticated calculations, it is impossible to create a "unpredictable" character string in a pure sense because its principle was programmed by someone as it goes through .

Therefore, in the world of physics, methods to generate truly pure random numbers (true random numbers) have been studied for a long time. One of the answers is a device called a quantum random number generator using quantum physics, and we know that we can generate a very high level of random numbers. It is a quantum random number generator that has already been put to practical use and is on the market, but in many cases it is complicated and expensive as it is becoming a bottleneck. Mr. Sanginetti's research team succeeded in realizing such a device using a normal smartphone camera.

In the research team, the high-performance camera used also for the camera mounted in N9 and space observation "ATIK-383L"We measured the amount of photons detected by irradiating the light emitted from the green LED to each of the two.


The result is the graph below. The graph drawn by ATIK-383L in the upper row and the graph of N9 in the lower row show almost the same results, and it has been shown that random numbers can be generated by measuring the number of photons using smartphone cameras.


The important thing here is the high reliability of cryptography, but according to the research team's trial calculation, in order to find the regularity of random numbers generated using this technology It is necessary to repeat the computation for 10 118 rings, "When we calculate this at 1 Gbps speed, the time required for the analysis is" 10 billion years "from the birth of the universe to the present 10 It means that it will be necessary to repeat 80 times iteration. "It shows the conclusion that random number sequence which is the basis of encryption can be generated with high purity. In addition, the research team conducted various tests to verify the accuracy of random numbers and clarified that they passed all the exams.

With this mechanism, it is possible to generate random numbers at a rate of 1 Mbps, and the research team says that encryption of credit card information as well as encryption of e-mails and phone calls themselves can be done .

It is a smartphone that became widely used in less than 10 years after appearing in the world but this time it seems that the camera was able to generate very high quality random numbers and it was hardly predicted It turned out to have the potential ability. I would like to look forward to what kind of usage will be invented in the future.