Towards Quantum Enigma Cipher III -Communication performance-

Cloud computing system based on data centers has recently attracted considerable attention. In that system, all data are communicated via a high speed optical network between a customer and data center or between data centers. There is a serious threat so called "Eavesdropper data center business", which means the eavesdropper can get all data from the transmission line and sell specific data selected by the protocol analyzer to malicious people who want to get the secret data. So we need to consider cyber attack against Layer-1 (physical layer). Quantum cryptography has been developed to protect such an attack. In order to apply such a new security technologies, the communication performance is very important as well as its security, because the data speed is more than several Gbit/sec. This research note III will discuss communication performances of quantum key distribution (QKD) and quantum enigma cipher, and explaines that QKD based on single photon signals cannot realize appropriate data speed, but quantum enigma cipher can.