Comment on “A KLJN-Based Thermal Noise Modulation Scheme with Enhanced Reliability for Low-Power IoT Communication”

Salem et al. proposed an asymmetric Kirchhoff–Law–Johnson-Noise (KLJN) scheme using four resistors, termed P-Ther-Mod, for wired and wireless thermal noise modulation in low-power IoT applications. While the authors correctly derive bit error probability (BEP) expressions and demonstrate improved BER performance, the core idea of using multiple resistors with a truth table for bit interpretation to enhance security and reliability is not novel, for it was introduced in 2013 as the “multiple” KLJN (MKLJN) protocol. Furthermore, the claimed “low-power” advantage is questionable, as the four-resistor design consumes at least four times the power per exchanged bit compared to the classical two-resistor KLJN, without reducing the energy per bit. These aspects warrant clarification to properly contextualize the contributions of the P-Ther-Mod scheme.