Physical Layer Encryption Algorithm for Chaotic Optical OFDM Transmission against Chosen-Plaintext Attacks

We propose and analyze a novel physical layer security scheme with the capability of resisting the chosen plaintext attacks in OFDM data transmission. The proposed security scheme consists of a multiple-fold data encryption based on hyper digital chaos, which provides a huge key space. The first chaotic encryption is applied in the chaotic OFDM subcarrier allocation scrambling, both in time and frequency domains. The second encryption is the introduction of chaotic phase rotation of the OFDM signals, where the amount of phase rotation is determining by both of a chaotic sequence and the original input plain data. As a result, it provides a dynamic key system and the generated ciphertexts will be influenced by the original data, which is a core feature against the chosen-plaintext attacks. The proposed security scheme is successfully verified via numerical simulations.