Breaking Channel Reciprocity: How Malicious Reconfigurable Intelligent Surfaces Can Disrupt Wireless Key Generation

Core Concepts

An attacker can prevent legitimate users from agreeing on the same secret key by deploying a malicious reconfigurable intelligent surface (RIS) to break the channel reciprocity, a fundamental principle underlying channel reciprocity-based key generation (CRKG).

Abstract

The paper presents a new attack, called RIS-jamming, that can disrupt CRKG by leveraging the ability of a malicious RIS to manipulate wireless signals. The authors elaborate on three examples to implement the RIS-jamming attack: Using active non-reciprocal circuits on the RIS to create asymmetric signal reflections. Performing asynchronous RIS configurations to break the reciprocity of the RIS-induced channel. Reducing the signal-to-noise ratio (SNR) of the entire channel by designing the RIS to cancel out the direct link. The authors analyze the impact of RIS-jamming attacks on the secret key rate and show that they can significantly reduce the key generation rate compared to a scenario without a malicious RIS or with a harmless RIS. Simulation and experimental results validate the effectiveness of the RIS-jamming attacks. To mitigate such attacks, the authors propose a countermeasure called contaminated path removal-based CRKG (CPR-CRKG) that exploits wideband signals to separate the malicious RIS path from the legitimate channel paths. This allows legitimate users to still generate secret keys from the remaining paths even under RIS jamming.

Stats

The paper presents the following key metrics and figures: "The secret key rate can be expressed as R = log((βr + PL l=1 βℓ+ σ2) + log((β′ r + PL l=1 βℓ+ σ2) - log((βr + PL l=1 βℓ+ σ2)(β′ r + PL l=1 βℓ+ σ2) - (βr,r′ + PL l=1 βℓ)2)." "Comparing (30) and (27), it is observed that R2 is smaller than R0, since the additional term βr PL l=1 βℓ+ βrσ2 in the denominator of (30) is positive." "R3 is also smaller than R2, as 2βr PL l=1 βℓ+ 2βrσ2 + β2 r > βr PL l=1 βℓ+ βrσ2, which indicates that as a RIS-jamming attack, asynchronous RIS configurations works better than asymmetric RIS structures."

Quotes

"An attacker can prevent legitimate users from agreeing on the same key by deploying a malicious reconfigurable intelligent surface (RIS) to break the channel reciprocity, a fundamental principle underlying channel reciprocity-based key generation (CRKG)." "RIS-jamming attacks have a non-negligible negative effect on BDR and the proposed CPR-CRKG scheme can mitigate their impacts in wideband systems."

Key Insights Distilled From

RIS-Jamming

by Guyue Li,Pau... at arxiv.org 04-11-2024

https://arxiv.org/pdf/2303.07015.pdf

Deeper Inquiries

How can the proposed CPR-CRKG countermeasure be extended to handle more advanced RIS-jamming attacks beyond the three examples discussed in the paper

To extend the CPR-CRKG countermeasure to handle more advanced RIS-jamming attacks beyond the examples discussed in the paper, several strategies can be considered: Dynamic Countermeasures: Implementing dynamic countermeasures that can adapt to evolving RIS-jamming techniques. This could involve real-time monitoring of RIS behavior and adjusting the countermeasures accordingly. Machine Learning: Utilizing machine learning algorithms to detect patterns in RIS-jamming attacks and develop predictive models to anticipate future attack strategies. This can enhance the proactive defense mechanisms of CPR-CRKG. Collaborative Defense: Establishing collaborative defense mechanisms where multiple CPR-CRKG systems can share threat intelligence and coordinate responses to sophisticated RIS-jamming attacks. This collective approach can enhance the overall security posture against advanced threats. Encryption Enhancements: Integrating advanced encryption techniques within the CPR-CRKG framework to further secure the key generation process and protect against manipulation by malicious RIS devices. By incorporating these advanced strategies, the CPR-CRKG countermeasure can be strengthened to effectively mitigate a broader range of RIS-jamming attacks and enhance the security of channel reciprocity-based key generation in wireless networks.

What are the potential limitations or drawbacks of the CPR-CRKG approach, and how can they be addressed

While the CPR-CRKG approach presents a promising countermeasure against RIS-jamming attacks, there are potential limitations and drawbacks that should be considered: Resource Intensive: Implementing wideband signals for multipath separation, as proposed in CPR-CRKG, may require additional computational resources and signal processing capabilities, potentially increasing system complexity and overhead. Vulnerability to Advanced Attacks: The CPR-CRKG approach may still be susceptible to highly sophisticated RIS-jamming techniques that can circumvent multipath separation and other countermeasures. Continuous research and updates are necessary to address emerging threats. Deployment Challenges: Integrating CPR-CRKG into existing wireless networks may pose deployment challenges, especially in scenarios where RIS technology is widespread. Compatibility issues and scalability concerns need to be addressed. To address these limitations, continuous research and development are essential. Enhancements in algorithm efficiency, robustness testing against advanced attacks, and streamlined deployment strategies can help mitigate the drawbacks of the CPR-CRKG approach and improve its effectiveness in combating RIS-jamming threats.

Given the adversarial potential of RIS technology, what other security implications or attack vectors should be investigated in the context of future wireless networks

In the context of future wireless networks and the adversarial potential of RIS technology, several security implications and attack vectors should be investigated: RIS-Enabled Eavesdropping: Research should focus on the potential for RIS devices to be used for eavesdropping purposes, where malicious actors exploit RIS technology to intercept sensitive information exchanged between legitimate users. RIS-Induced Interference: Investigating the possibility of RIS devices causing intentional interference in wireless communications, disrupting network connectivity, and affecting the performance of neighboring systems. RIS Manipulation: Exploring the risks associated with unauthorized manipulation of RIS configurations, such as unauthorized changes to reflection coefficients or signal modulation, leading to unauthorized access or data manipulation. RIS-Based Denial of Service (DoS): Analyzing the potential for RIS devices to be used in DoS attacks, where attackers deploy RIS technology to overwhelm network resources, disrupt communication channels, and render systems inoperable. By addressing these security implications and investigating potential attack vectors related to RIS technology in future wireless networks, researchers and practitioners can develop robust defense mechanisms and proactive security measures to safeguard network integrity and protect against emerging threats.