Photonic-Assisted Secure Millimeter Wave Communication with Quantum Noise Randomized Stream Cipher

Security enhancement is a major challenge in future wireless transmission systems. This study reports photonic-assisted physical layer encryption (PLE) based on quantum-noise signal masking. PLE is a signal-level symmetric key encryption that directly protects millimeter-wave signals from being illegitimately received by an eavesdropper without a symmetric seed key. A 4.25-Gbit/s orthogonal frequency division multiplexing quantum-noise randomized quadrature amplitude modulation cipher is generated at 1.875 GHz via intensity-modulation/direct-detection analog intermediate-frequency-over-fiber transmission with a directly modulated laser. Following the optical signal delivery and encryption based on the quantum-noise signal masking, the intermediate frequency is upconverted to 59 GHz, and V-band secure wireless transmission is demonstrated. The system achieves unique signal security that can never be reduced without sacrificing signal quality.