Updating quantum cryptography and communications

Charles H. Bennett, Gilles Brassard A

健太郎 和久井

David S. Simon, Gregg S. Jaeger, Alexander V. Sergienko

Ana Jancic, Matthew J. Warren

\n\t\t\t\t\tMost of cryptographic techniques today provide secure enough communications in society. However, none of them can provide unconditional security (except One-Time pad, which is the only such mechanism). They all have weaknesses. That is why they should be consistently updated and renovated along with changes in technology. However, the quantum computers have potential to completely revolutionize cryptography. They would be so powerful that all complex computations and mathematical problems on which current cryptography rely, would become trivial. They would be able to solve them in a matter of seconds. At the same time quantum cryptography would offer perfectly secure communication. This paper is brief introduction to quantum computing, quantum cryptography, and to existing quantum technology. \n\t\t\t\t

David S. Simon

Saswato R. Das

Researchers in Europe in the field of quantum cryptography have demonstrated for the first time that it should be possible? with the help of satellites? to communicate across thousands of kilometers using unbreakable codes whose security is guaranteed by the laws of quantum physics. For many business or government uses, the codes must be usable between cities and continents, but quantum cryptography machines today are limited to about 150 kilometers by the length of individual optical fibers and the loss of photons within them.