Physical layer security based on chaotic maps applied to OFDM systems

Recently, physical layer security (PLS) has attracted widespread attention to improve security in networks without focusing on encryption techniques at the higher layers. This paper proposes a PLS scheme through an orthogonal frequency division multiplexing (OFDM) system based on chaotic maps. An OFDM wave is securedby mixing its modulated symbols and encoding information bits at the same time. Informationis encoded by generating a stream of bits by chaotic maps. To build a secure OFDM wave, the modulated symbols are shuffled by a scrambling matrix that is created by chaotic maps. Their initial conditions act as a secret shared key. We send only one key to encrypt the first OFDM signal at the beginning of the transmission. After the first transmission, the received information, after its decryption, s e rv e as the key to the next information. In other word, the information itself is the key to the next information to be received.Meanwhile, we do not have to send the encryption key on every transmission.