Secrecy of Molecular Communication in Presence of Radiation Absorption

Ultra high user density is one of the key requirements in 6G and beyond. Also, in future, THz based communication system and Molecular Communication (MC) will coexist. In such coexist scenarios, Electromagnetic (EM) radiation and in subsequent molecular absorption leads to Radiation Absorption Noise (RAN). However, the RAN and in turn Molecular Information Transfer (MIT) greatly depends on different realistic parameters of human tissues and polarization factor of incident EM radiation. On the other hand, in MC, limited computational capabilities of the information molecules limit them to discriminate against the presence of Bob or Eve. Effect of different parameters of human tissues and polarization factor of incident EM radiation on the secrecy of MC system is modelled and analysed in this research. Basically, this research presents different secrecy measures of the MC system under RAN and therefore, it’s effect on MIT is presented. In particular, closed form expressions of different secrecy metrics such as, Secrecy Outage Probability (P_OUT (Rs)), and Probability of Non-Zero Secrecy Capacity (P_NZ-SC (Rs)) are derived in this research work. The effect of impedance of various human tissues like brain, skin and bloods, the effect of polarization factor of incident EM radiation and the effect radiation frequency on each of the proposed secrecy metrics is demonstrated. Different simulated results show a perfect match with the theoretical background. The proposed research is useful in implementation of a secure MC system in a scenario where THz based communication system coexists with MC.