Channel-Based Dynamic Key Generation for Physical Layer Security in OFDM-PON Systems

Key generation and distribution is a fundamental problem of communication security. To avoid the potential risk due to static key, a physical-layer dynamic key generation and encryption scheme is proposed for orthogonal frequency division multiplexing passive optical network (OFDM-PON) systems. By exploiting the inherent channel randomness, the shared secret key between the OLT and ONU is generated and renewed periodically, thereby effectively improving the security against malicious attacks. The transmission experiment of 3.5 Gb/s 16-quardrature-amplitued-modulatin encrypted OFDM data is successfully demonstrated over a 25 km standard single-mode fiber. The key space of the proposed encryption scheme reaches 10
⁶⁶
, which provides privacy between users and protection against eavesdropping.