Two-dimensional encryption system for secure free-space optical communication of time-series data streams

Abstract

The importance of encryption in free-space optical communication systems has been increasing due to their widespread use. Herein, for the first time, the authors propose a novel two-dimensional encryption system for free-space optical communication using two spatial patterns as encryption keys. A data stream is physically encrypted with optical signals to reduce the risk of unauthorised third-party intrusion into communication. The encryption and restoration of a binary data stream using the proposed encryption system are confirmed by simulation results. The authors believe that, in the future, the proposed system could be used as an encryption method at the physical layer level to achieve the desired level of safety determined by the user.