not-yet-known not-yet-known not-yet-known unknown This commentary critically reviews the 2024 article ”Kirchhoff meets Johnson: In pursuit of unconditionally secure communication” by Ertugrul Basar, focusing on claims regarding the originality, security, and energy efficiency of thermal noise-based secure communication systems. The article presents the Kirchhoff-law-Johnson-noise (KLJN) key exchange scheme and wireless noise modulation as breakthroughs in security; this review clarifies their historical foundation, practical limitations, and security vulnerabilities. Key issues discussed include proper attribution to pioneering work by Kish (2005–2006), feasibility of unconditional security for wireless adaptations, and exaggerated claims of low-power operation. The aim is to contextualize this field’s evolution for engineering audiences and stimulate more precise scholarship and realistic expectations for future research directions.
not-yet-known not-yet-known not-yet-known unknown This commentary critically reviews the 2024 article ”Kirchhoff meets Johnson: In pursuit of unconditionally secure communication” by Ertugrul Basar, focusing on claims regarding the originality, security, and energy efficiency of thermal noise-based secure communication systems. The article presents the Kirchhoff-law-Johnson-noise (KLJN) key exchange scheme and wireless noise modulation as breakthroughs in security; this review clarifies their historical foundation, practical limitations, and security vulnerabilities. Key issues discussed include proper attribution to pioneering work by Kish (2005–2006), feasibility of unconditional security for wireless adaptations, and exaggerated claims of low-power operation. The aim is to contextualize this field’s evolution for engineering audiences and stimulate more precise scholarship and realistic expectations for future research directions.
Abstract Noise: an enemy to be dealt with and a major factor limiting communication system performance. However, what if there is gold in that garbage? In conventional engineering, our focus is primarily on eliminating, suppressing, combating, or even ignoring noise and its detrimental impacts. Conversely, could we exploit it similarly to biology, which utilizes noise‐alike carrier signals to convey information? In this context, the utilization of noise, or noise‐alike signals in general, has been put forward as a means to realize unconditionally secure communication systems in the future. In this tutorial article, we begin by tracing the origins of thermal noise‐based communication and highlighting one of its significant applications for ensuring unconditionally secure networks: the Kirchhoff‐law‐Johnson‐noise (KLJN) secure key exchange scheme. We then delve into the inherent challenges tied to secure communication and discuss the imperative need for physics‐based key distribution schemes in pursuit of unconditional security. Concurrently, we provide a concise overview of quantum key distribution schemes and draw comparisons with their KLJN‐based counterparts. Finally, extending beyond wired communication loops, we explore the transmission of noise signals over‐the‐air and evaluate their potential for stealth and secure wireless communication systems.
The Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange scheme leverages statistical physics to enable secure communication with zero average power flow in a wired channel. While the original KLJN scheme requires significant power for operation, a recent wireless modification, TherMod, proposed by Basar claims a “low power” implementation. This paper critically examines this claim. We explain that the additional components inherent in the wireless adaptation substantially increase power consumption, rendering the “low power” assertion inappropriate. Furthermore, we clarify that the security claims of the original KLJN scheme do not directly translate to this wireless adaptation, implying significant security breach. Finally, the scheme looks identical to one of the stealth communicators from 2005, which was shown not to be secure.
Abstract There is an ongoing debate about the fundamental security of existing quantum key exchange schemes. This debate indicates not only that there is a problem with security but also that the meanings of perfect, imperfect, conditional and unconditional (information theoretic) security in physically secure key exchange schemes are often misunderstood. It has been shown recently that the use of two pairs of resistors with enhanced Johnsonnoise and a Kirchhoff-loop ‒ i.e., a Kirchhoff-Law-Johnson-Noise (KLJN) protocol ‒ for secure key distribution leads to information theoretic security levels superior to those of today’s quantum key distribution. This issue is becoming particularly timely because of the recent full cracks of practical quantum communicators, as shown in numerous peer-reviewed publications. The KLJN system is briefly surveyed here with discussions about the essential questions such as (i) perfect and imperfect security characteristics of the key distribution, and (ii) how these two types of securities can be unconditional (or information theoretical).
A secure key distribution (exchange) scheme is unconditionally secure if it is unbreakable against arbitrary technological improvements of computing power and/or any development of new algorithms. There are only two families of experimentally realized and tested unconditionally secure key distribution technologies: quantum key distribution (QKD), the base of quantum cryptography, which utilizes quantum physical photonic features, and the Kirchhoff-Law–Johnson-Noise (KLJN) system that is based on classical statistical physics (fluctuation–dissipation theorem). The focus topic of this paper is the thermodynamical situation of the KLJN system. In all the original works, the proposed KLJN schemes required thermal equilibrium between the devices of the communicating parties to achieve perfect security. However, Vadai et al., in (Nature) Sci. Rep. 5, 13653 (2015) show a modified scheme, where there is a non-zero thermal noise energy flow between the parties, yet the system seems to resist all the known attack types. We introduce an attack type against their system. The attack utilizes coincidence events between the line current and voltages. We show that there is a non-zero information leak toward the Eavesdropper, even under idealized conditions. As soon as the thermal equilibrium is restored, the system becomes perfectly secure again. In conclusion, perfect unconditional security requires thermal equilibrium.
There is an ongoing debate about the fundamental security of existing quantum key exchange schemes. This debate indi cates not only that there is a problem with security but also that the meanings of perfect, imperfect, conditional and unconditional (information theoretic) security in physically secure key exchange schemes are often misunderstood. It has been shown recently that the use of two pairs of resistors with enhanced Johnsonnoise and a Kirchhoff-loop ‒ i.e ., a Kirchhoff-Law-Johnson-Noise (KLJN) protocol ‒ for secure key distribution leads to information theoretic security levels superior to those of today’s quan tum key distribution. This issue is becoming particularly timely because of the recent full cracks of practical quantum communicators, as shown in numerous peer- reviewed publications. The KLJN system is briefly surveyed here with discussions about the essential questions such as ( i) perfect and imperfect security characteristics of the key distribution, and ( ii ) how these two types of securities can be unconditional (or information theoretical).
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.