Protocols Study Of Quantum Virtual Private Network In Passive Optical Network

Passive optical network (PON) technology is the key technology to break bottleneck of "the last kilometer"; however, the problem of the security of PON has not been solved well. Since the optical line terminal is always active in the whole procedure of communication, i.e., OLT can easily capture the information exchanging between any two of the optical network units. Considering the unique secrecy characteristics of quantum cryptography communication, we introduce the quantum cryptography technology to the conventional PON network to provide an efficient solution for the weak security of it. And a new conception of quantum virtual private network (VPN) is proposed.The thesis is devoted to designing the proper quantum cryptography communication protocols based on the architecture and characteristics of PON network. Based on these protocols, the realization of quantum VPN technology and the corresponding experimental scheme have been studied. The main results are achieved as follows:As for quantum key distribution (QKD), an efficient unsymmetrical quantum key distribution protocol is proposed with detailed security analysis based on Greenberger-Horne-Zeilinger states. Compared with other QKD protocols, it owns larger channel capacity and higher efficiency. An efficient QKD protocol with quantum identity authentication (QIA) based on the modified architecture model of PON is presented following with security proofs from the aspect of information theory. In this scheme, both of QIA and QKD between optical line terminal and optical network unit and between any two of the authorized optical network units are implemented. Based on QIA, the authorized optical network units form the VPN. With the shared key and proper encryption scheme, the quantum cryptography communication between any two authorized users can be achieved.In the field of quantum secret sharing (QSS), based on multi-target quantum teleportation, a novel secret sharing protocol is proposed, which not only can be used to share quantum state information, but also reduces the concentration of the secret information and enhance the security of secret sharing contrast with the conventional QSS protocols. Analytical results show the proposed protocol is secure and feasible. Moreover, the protocol can be applied well in the modified PON architecture model. Based on the proposed QSS protocol, a quantum secret information transmission sharing scheme is proposed, which can be applied to implement the quantum secret sharing and secret information transmission for the ONUs, then the quantum VPN is formed.In point of quantum secure direct communication (QSDC), based on modified PON architecture model, two QSDC schemes with QIA are proposed. In these two schemes, QIA and QSDC can be well implemented between any two legitimated users in the virtual private network, which provide another kind of efficient solutions for the formation of quantum VPN. The proposed information theory analysis for QSDC also provides a method for the security proofs.