关键词: virtual private network, quantum key, identity authentication, key generation rate, quantum bit error rate, throughput

Abstract: Traditional virtual private networks (VPNs) are conditional security. In order to ensure the security and confidentiality of user data transmission, a model of quantum VPN based on Internet protocol security (IPSec) protocol is proposed.By using quantum keys for key distribution and entangled particles for identity authentication in the network, a secure quantum VPN is relized. The important parameters affecting the performance of the VPN was analyzed. The quantitative relationship between the security key generation rate, the quantum bit error rate (QBER) and the transmission distance was obtained. The factors that affect the system throughput were also analyzed and simulated. Finally, the influence of the quantum noise channel on the entanglement swapping was analyzed. Theoretical analysis and simulation results show that, under a limited number of decoy states, with the transmission distance increased from 0 to 112.5 km, the secure key generation rate was reduced from 5.63×10^-3 to1.22×10^-5  . When the number of decoy states is fixed, the QBER increases dramatically with the increase of the transmission distance, and the maximum reaches 0.393. Analysis shows that various factors in communication have a significant impact on system throughput. The generation rate of the effective entanglement photon pairs have decisive effect on the system throughput. Therefore, in the process of quantum VPN communication, various parameters of the system should be properly adjusted to communicate within a safe transmission distance, which can effectively improve the reliability of the quantum communication system.

Key words: virtual private network, quantum key, identity authentication, key generation rate, quantum bit error rate, throughput