A Practical Algorithm for Physical Layer Encryption Under Constant Envelope Constraint

Physical Layer Encryption (PLE) techniques have gained increasing attention recently as they ensure security without requiring heavy coordination or time-consuming secret key establishment. In particular, masking encryption techniques rely on transmitting a masking signal along with the data signal to prevent eavesdroppers from deciphering the transmitted information by degrading its channel. These methods are especially practical, as they do not require any knowledge of the eavesdroppers channel state. Several mask designs have been proposed in the literature in recent years. However, these methods suffer from various limitations, including vulnerability to brute-force attacks, and a limited range of potential use cases. In this paper, we present a novel mask design algorithm that offers three key advantages compared to state-of-the-art methods: optimal Peak-to-Average Power Ratio (PAPR), applicability to both Gaussian and flat fading channels, and a high level of confidentiality. These advantages are validated through our simulations.