Quantum Secure Communication Strengthens IoV Networks

By Dr Silpaja Chandrasekar, PhDReviewed by Susha Cheriyedath, M.Sc.Oct 2 2024

In a paper published in the journal IScience, researchers explored the security vulnerabilities of Internet of Vehicles (IoV) networks against future quantum computers, particularly due to the threat posed by Shor's algorithm.

To address this, the researchers proposed a continuous-variable quantum secure direct communication (CV-QSDC) protocol, using orbital angular momentum (OAM) as the information carrier to resist quantum attacks. The protocol leverages the compatibility of continuous-variable quantum systems with standard telecommunication technologies, along with the higher information capacity offered by OAM eigenstates.

Related Work

Previous research on IoV security has highlighted vulnerabilities in cryptographic algorithms against quantum computing, particularly due to Shor’s algorithm, which compromises Rivest–Shamir–Adleman (RSA) and elliptic curve cryptography (ECC). To address this, researchers proposed quantum secure direct communication (QSDC) as a solution, eliminating key distribution vulnerabilities by using a single quantum communication channel.

Initial advancements in QSDC protocols, including measurement-device-independent (MDI) structures and high-dimensional encoding, have enhanced both security and efficiency. These breakthroughs laid the foundation for discrete-variable (DV) and continuous-variable (CV) quantum communication in IoV networks.

Quantum Security in IoV

Quantum IoV security has become a critical concern due to the vulnerabilities introduced by advances in quantum computing. Traditional cryptographic algorithms like RSA and ECC, which rely on complex mathematical problems such as integer factorization and discrete logarithms, are at risk of being compromised by Shor’s algorithm, making them theoretically insecure against future quantum computers.

In response, researchers have proposed QSDC as a promising alternative. QSDC removes the need for pre-shared keys—a significant vulnerability in classical systems—by using a single quantum communication channel to transmit secret messages directly between trusted parties. This method significantly reduces the risk of key distribution attacks, enhancing security for IoV networks.

Key advancements in QSDC development include the two-step protocol, which streamlined communication processes, and the introduction of measurement-device-independent (MDI) structures, which mitigated vulnerabilities associated with device imperfections. High-dimensional encoding further improved the security and efficiency of these protocols, making them more resistant to eavesdropping attacks.

These breakthroughs have established the foundation for both DV and CV quantum communication systems in IoV networks. DV systems rely on single-photon detection, while CV systems utilize continuous light and homodyne detectors, providing greater compatibility with existing telecommunication technologies. Together, these approaches offer a robust and secure framework for IoV communication in the face of quantum threats.

Asymptotic and Finite-Size Security

The section on asymptotic regime security in the CV-QSDC protocol addresses how detection light beams (S1 and S2) are transmitted through the same atmospheric turbulence channel, ensuring protocol security. An entanglement-based (EB) model is used to analyze the effective information of detection light.

In cryptographic and quantum communication contexts, Alice and Bob are conventional placeholder names representing the sender and receiver of information, respectively. In this case, Alice prepares a pair of two-mode squeezed states, and the covariance matrix is defined to reflect the state after passing through turbulence. Key parameters, such as transmittance and excess noise, are introduced to characterize the system, enabling the evaluation of effective information regarding atmospheric turbulence and noise levels.

For the CV-QSDC protocol with reverse reconciliation, the effective information is mathematically expressed, incorporating mutual information, detection-added noise, and total noise. The Holevo quantity is also defined to assess security against collective attacks. This framework provides insights into the protocol's performance under varying noise conditions, demonstrating robustness against excess noise.

The results show that the effective information remains relatively stable across different scenarios, reinforcing the protocol’s security in practical applications. However, transitioning to finite-size security, the discussion emphasizes that previous calculations assumed an infinite number of signals, which is not feasible in real-world conditions.

In the finite-size regime, Alice and Bob exchange a finite number of signals. The effective information is redefined to account for the number of signals used for parameter estimation and privacy amplification, considering the impact of finite signal lengths on security.

The relationship between effective information and transmission distance is explored, revealing that while the maximum effective information in the finite-size regime is lower than in the asymptotic regime, it presents a more realistic picture of the protocol's capabilities. As the number of signals increases, transmission distance improves, but remains constrained by practical limitations. Overall, these findings lay a solid foundation for implementing QSDC protocols in IoV networks, highlighting the balance between theoretical security and real-world applicability.

Conclusion

To summarize, this study introduced a CV-QSDC protocol for IoV networks to deliver secret messages directly while ensuring compatibility with standard telecommunication technology for imperceptibility and security. OAM eigenstates served as information carriers, boosting wireless communication capacity.

The protocol calculated effective information and maximum transmission distance in both asymptotic and finite-size regimes, with the latter providing a more realistic perspective. Information block mapping was utilized in the message transmission stage to reduce security risks from one-eigenstate distribution, emphasizing its importance for emergency communication scenarios. The protocol demonstrated significant potential for enhancing secure communications in various practical applications.

Journal Reference

Zhao, W., et al. (2024). Quantum Secure Direct Communication in Internet of Vehicles. IScience, 110942–110942. DOI: 10.1016/j.isci.2024.110942, https://www.sciencedirect.com/science/article/pii/S2589004224021679

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