Computational Secure Physical Layer Algorithm for MIMO Wireless Systems

A computationally secure physical layer wireless communication multiple-input-multiple-output (MIMO) system is proposed and analyzed in this article. The proposed algorithm is shown to be general for arbitrary MIMO systems, and very robust against brute-force attacks and cryptanalysis techniques. The algorithm relies on the knowledge of the wireless channel statistics between the transmitter and the legitimate receiver through channel reciprocity, which is random and varies every coherence time. Both the transmitter and the legitimate receiver create a permutation vector from the sorted powers of the channel fading paths from each transmit antenna to all receive antennas. The generated permutation vector is used to shuffle the rows of the constellation matrix creating the security key. It is reported that the number of possible combinations is huge, especially for large MIMO configurations, which makes key decryption nearly impossible even with advanced supercomputers. For illustration purposes, several MIMO techniques are considered in this study, including space shift keying (SSK), quadrature SSK, quadrature spatial modulation, and spatial multiplexing.