Quantum cryptography becomes a reality
According to reliable sources from NEC, Commercial quantum cryptography, a revolutionary system that can produce quantum keys at a speed of 100Kbit/s and then broadcast it up to 40 kilometres along the commercial fibre optic lines will be available in the markets by the second half of 2005. Speaking in line with Kazuo Nakamura, senior manager of NEC's quantum information technology group at the company's Fundamental and Environmental Research Laboratories, it can be considered as a world record as it is a rare blend of speed and distance. As put by Akio Tajima, the assistant manager at the laboratory, this innovative concept has gone through several improvisations after it was successfully tested in April at the companys laboratories in Tokyo.
The system permits the users to swap the keys with a prior idea that they have not been disordered up during the transmission. The whole system works on the concept that the system works by implanting the encryption key on photons, which can be either in the receiver end or with an eavesdropper, as the photons cannot be cracked. Akio Tajima said that until last April the round-trip quantum cryptography method at NEC where it had a laser as well as a receiver at one end and also a mirror at the other end, faced some troubles regarding the high speed over long distances.
Earlier the detector that turns the photons to electrons once they collide with it functioned very slowly. This created a problem in registering these photons, as there will be an avalanche of electrons with every collision. The team lead by Tajima has rectified that disadvantage now by developing a new detector that can work reliably at 100Kbit/s. This fast pace helps in clearing this whole bunch of electrons produced by the collision from the device, quickly so that they can register the next photon. The NEC scientists have also rectified the problem with the mirror used earlier in the system called the faraday mirror. The performance of this mirror, which can reflect the light in a 90-degree rotation from the input light, changes with temperature leading to quality loss. NEC today has improvised this concept of mirror, by producing a mirror that works efficiently with temperature variations.
Another advantage of NEC system is that it has a conventional laser, which can transmit the photons through the fibre optic cables over a long distance with very less noise. Although there were powerful lasers that could trigger the propagation of photons over long distances, they all resulted in more noises leading to efficiency loss. According to Nakamura 'This is the world's fastest key generation technology at 40 kilometres'. He confirms his statement with various proofs. He said that the University of Geneva has achieved quantum transmission over a distance of over 60 kilometres, but at a much lower speed, while a system developed by Japan's National Institute of Advanced Industrial Science and Technology, a major government laboratory, has achieved nearly the same speed as NEC's system, but only at about half the distance.
According to Toshiyuki Kanoh, chief manager of the company's System Platforms Research Laboratories, this break through system invented in collaboration with the Japan Science and Technology Agency's Exploratory Research for Advanced Technology and Japan's National Institute of Information and Communications Technology, will take an year to be launched in the commercial market as its software is still on the developing stage. He also added that they are going to create a commercial market for the system which it lacks now and is expecting the police, banks and financial institutions etc to be its clients by the mid of 2005. There is also a move to demonstrate this system in various exhibitions and seminars.
