HTML5 Webook

8/84

of “physical layer cryptography” that integrates information theory and the technology of cryptography. is enables the construction of a new global secure network that is based on optical space communication. On the basis of these new trends, a new and excellent network with safety and high transmission eciency that covers from ground optical ber networks to satellites is called a “quantum optical network.” is and the “quantum node” were set as the main themes of the Fourth Medium-to Long-Term Plan.e framework in which information is expressed by bit sequences of 0s and 1s based on Shanon’s theorem is now being fully reconstructed by including the bottom layer of physics of “quanta” (the quantum layer). e quantum layer viewpoint most widely captures ICT sys-tems, thereby bringing new knowledge to science and in-novating ICT itself. is special issue presents our latest eorts on this subject.Masahide SASAKI, Ph.DDistinguished Researcher, Advanced ICT Research InstituteQuantum communication, Quantum cryptography1 Intoroduction4　　　Journal of the National Institute of Information and Communications Technology Vol. 64 No. 1 (2017)