Protecting Physical Layer Secret Key Generation from Active Attacks

Abstract

Lightweight session key agreement schemes are expected to play a central role in building Internet of things (IoT) security in sixth-generation (6G) networks. A well-established approach deriving from the physical layer is a secret key generation (SKG) from shared randomness (in the form of wireless fading coefficients). However, although practical, SKG schemes have been shown to be vulnerable to active attacks over the initial “advantage distillation” phase, throughout which estimates of the fading coefficients are obtained at the legitimate users. In fact, by injecting carefully designed signals during this phase, a man-in-the-middle (MiM) attack could manipulate and control part of the reconciled bits and thus render SKG vulnerable to brute force attacks. Alternatively, a denial of service attack can be mounted by a reactive jammer. In this paper, we investigate the impact of injection and jamming attacks during the advantage distillation in a multiple-input–multiple-output (MIMO) system. First, we show that a MiM attack can be mounted as long as the attacker has one extra antenna with respect to the legitimate users, and we propose a pilot randomization scheme that allows the legitimate users to successfully reduce the injection attack to a less harmful jamming attack. Secondly, by taking a game-theoretic approach we evaluate the optimal strategies available to the legitimate users in the presence of reactive jammers.

A Physical Layer, Zero-Round-Trip-Time, Multifactor Authentication Protocol

“…Fading is a complex physical process process, including both large scale fading (path loss and shadowing) and small scale fading components. With respect to their role in security applications, in [29] and [30] it has been noted that large scale fading is primarily useful for node authentication (e.g., through high precision localization), while small scale fading is a valuable source of entropy for SKG [59]. The separation of the two types of processes can in principle be performed in the time or in the power domain.…”

Physical Layer Security - from Theory to Practice

“…Furthermore, active attacks have been addressed in [9], [10] and hybrid designs of authenticated encryption leveraging SKG along with symmetric block ciphers have appeared in [32]. As a result, SKG emerges as one of the most mature and promising PLS technologies for 6G.…”

“…In communications, especially wireless, the propagation channel itself can be such a random source, allowing it to be used to distill secret keys, which can be used for pairing and encryption. The corresponding procedures are well studied and numerous practical demonstrators have been developed [8] along with and concrete countermeasures in the case of active attacks [9], [10].…”

Star-specific Key-homomorphic PRFs from Linear Regression and Extremal Set Theory

“…For detailed introduction to the topic and its applications in different settings, we refer the interested reader to [30,211,237,19,154,326,236,93]. In this manner, channel state randomization can be used to effectively reduce an MITM attack to the less harmful jamming attack [221]. See [252] for a thorough introduction to jamming and anti-jamming techniques.…”