Security Performance of Public Key Distribution in Coherent Optical Communications Links

Theoretical uncertainties associated with the measurement of quantum bits have made Quantum Key Distribution (QKD) an attractive research topic for secure communication systems. Recent research in this area has focused on using weak coherent laser pulses as the carrier instead of the traditional approach of using single photon carriers. This opens the possibility to implement QKD infrastructure that is compatible with the existing optical fiber communication network. In this work, we report a theoretical study of a new approach that utilizes the Quantum Public Key Envelope (QPKE) based on the randomized Glauber states in a classical coherent optical communication system to obtain a secure communication. We verify the efficacy of the system using numerical simulation. We also study the possible approaches for an eavesdropper to test the degree of security enhancement of the proposed system at bitrate of 56 Gb/s. Two eavesdropping techniques are proposed for security analysis. A set of security parameters are used to simulate the variety of eavesdropping schemes.