Smart Cities rely on high-density digital infrastructures that include Internet of Things (IoT) devices, Artificial Intelligence (AI), cloud computing, digital identity systems, and operational technology. Although these systems improve efficiency and sustainability, they also provide a large cyber-physical attack surface. The problem is exacerbated by the advent of quantum computing, as popular public-key ciphers like RSA and elliptic-curve cryptography can be broken using quantum algorithms such as Shor's algorithm (Shor, 1994; Mosca, 2018). Smart cities rely on long-term data confidentiality, certificate-based trust, and remote management of critical infrastructure. This presents a strategic cyber resilience challenge. This thesis examines the impact of quantum technology on smart cities' cyber resilience, as well as how quantum-safe mechanisms can be integrated into urban digital infrastructure. The updated proposal now includes a critical literature review, case reasoning by comparison, a threat and vulnerability matrix, and a simulated BB84 quantum key distribution demonstration. According to NIST (2024b, 2024c, 2024d) and Pirandola et al. (2020), this thesis supports post-quantum cryptography (PQC) NIST standards FIPS 203, FIPS 204, and FIPS 205 as a scalable software migration strategy and quantum key distribution (QKD) as a selective protection strategy for high-value fixed communication links. The analysis demonstrates that quantum-safe resilience cannot be achieved solely through one technology. Any practical smart city transition must include a cryptographic inventory, data lifetime assessment, risk-based prioritization of critical services, hybrid migration, continuous monitoring, and governance. According to the simulation, the quantum bit error rate increases during the intercept-resend attack, alerting Alice and Bob to the eavesdropping activity and allowing them to discard the common key. The proposed framework integrates post-quantum cryptography for a wide range of software and cloud services, quantum key distribution for specific critical infrastructure links, and NIST Cybersecurity Framework 2.0 governance functions to ensure ongoing operational resilience.
Smart Cities rely on high-density digital infrastructures that include Internet of Things (IoT) devices, Artificial Intelligence (AI), cloud computing, digital identity systems, and operational technology. Although these systems improve efficiency and sustainability, they also provide a large cyber-physical attack surface. The problem is exacerbated by the advent of quantum computing, as popular public-key ciphers like RSA and elliptic-curve cryptography can be broken using quantum algorithms such as Shor's algorithm (Shor, 1994; Mosca, 2018). Smart cities rely on long-term data confidentiality, certificate-based trust, and remote management of critical infrastructure. This presents a strategic cyber resilience challenge. This thesis examines the impact of quantum technology on smart cities' cyber resilience, as well as how quantum-safe mechanisms can be integrated into urban digital infrastructure. The updated proposal now includes a critical literature review, case reasoning by comparison, a threat and vulnerability matrix, and a simulated BB84 quantum key distribution demonstration. According to NIST (2024b, 2024c, 2024d) and Pirandola et al. (2020), this thesis supports post-quantum cryptography (PQC) NIST standards FIPS 203, FIPS 204, and FIPS 205 as a scalable software migration strategy and quantum key distribution (QKD) as a selective protection strategy for high-value fixed communication links. The analysis demonstrates that quantum-safe resilience cannot be achieved solely through one technology. Any practical smart city transition must include a cryptographic inventory, data lifetime assessment, risk-based prioritization of critical services, hybrid migration, continuous monitoring, and governance. According to the simulation, the quantum bit error rate increases during the intercept-resend attack, alerting Alice and Bob to the eavesdropping activity and allowing them to discard the common key. The proposed framework integrates post-quantum cryptography for a wide range of software and cloud services, quantum key distribution for specific critical infrastructure links, and NIST Cybersecurity Framework 2.0 governance functions to ensure ongoing operational resilience.
With the arrival of fault-tolerant quantum computers, an existential threat has come to the cryptographic underpinnings of the security infrastructure in place for modern information technologies. Virtually all secure digital communication protocols used today are based on classical public-key cryptographic systems – RSA, Elliptic Curve Cryptography (ECC) and Diffie-Hellman key exchange – that are susceptible to polynomial-time quantum attacks using Shor's algorithm. Symmetric cryptographic algorithms that are not broken are being effectively halved by Grover's algorithm, for example, AES. In this article, a complete and journal-standard systematic review of quantum computing and its implications in the field of information technology security is presented which includes 22 peer-reviewed publications from 2023-2025. The study covers the basics of quantum computing (qubits, superposition, entanglement and quantum gates), and how quantum computing specifically poses a threat to classical cryptography via algorithmic mechanisms. The three post-quantum cryptographic algorithms that were standardised by the National Institute of Standards and Technology (NIST) in August 2024 (ML-KEM, FIPS 203; ML-DSA, FIPS 204; and SLH-DSA, FIPS 205) are compared based on their security assumptions, performance, and readiness for deployment. The practical limitations and the use of Quantum Key Distribution, (QKD), as a physics based alternative to the computational security assumptions are discussed. Results show that although mature PQ solutions are now available for most cryptographic applications, the migration challenge, including legacy system transitions, migration architecture, and governance, is significant and pressing as the ‘harvest now, decrypt later’ threat model is relevant and adversaries might be collecting encrypted data for quantum decryption. The impact for financial services, health care, government, cloud infrastructure and critical national infrastructure is discussed. Lastly, the researchers list key research areas: standardisation of quantum-safe protocols, hybrid PQC-QKD designs, light-weight PQC for constrained devices, and quantum-safe blockchain.
The evolution of smart cities will contribute to an increase in the use of interconnected physical/digital ecosystems, and consequently, an increase in threat surface for the cyber threats against the protected data streams. With the emergence of quantum-based cyberthreats, this has increased the potential range of types of cyber-attacks on protected data and increased the use of quantum-based means of conducting cyber-attacks on protected data. This research proposal presents an Internet of Things (IoT) smart city framework founded on quantum-secure standards that were developed for next-generation IoT smart cities. The IoT Smart City Framework is comprised of four levels of architecture: a Quantum Backbone, a Key Management Level, an Edge Gateway Level, and an IoT Device Layer. Consequently, through the use of this architecture, the IoT Smart City Framework can protect the IoT Smart City Network from future cybercriminal attacks while providing assurance that the IoT Smart City Framework has been 'future-proofed.' By utilizing strategically deployed quantum nodes, the proposed solution performs QKD and frees devices with limited resources from needing to perform highly computationally intensive cryptography in order to secure encrypted communications, instead employing Lightweight Encryption Standards in conjunction with Symmetric Keys established via QKD. Using simulated quantum channels and urban IoT workloads, our experimental results yield secret key rates between 12 and 18 kilobits/sec (kbps) with a low quantum bit error rate (QBER) of 1.8% to 3.2%. Based on these experimental results, we conclude that the proposed hierarchical security architecture provides a resilient security framework for urban essential services, with negligible energy consumption.
Quantum computing is no longer a distant concern for cybersecurity planning. Its progress has raised serious questions about the long-term reliability of widely used public-key cryptographic systems, especially RSA, elliptic curve cryptography, and related key exchange mechanisms that currently protect digital communication, cloud services, financial transactions, government systems, and enterprise information assets. The main concern is that powerful quantum algorithms could weaken the mathematical assumptions on which these systems depend, creating future risks for encrypted data, digital signatures, identity systems, and secure network protocols (Shor, 1994; Mosca, 2018). Post-quantum cryptography has therefore become a major cybersecurity readiness priority, not only as a technical replacement for vulnerable algorithms, but as a broader organizational migration challenge. Effective preparation requires cryptographic asset inventory, risk classification, crypto-agility, vendor coordination, interoperability testing, and phased deployment across complex information systems (Kumar, 2022; Campbell, 2025). This article examines the cybersecurity implications of quantum computing and reviews the major post-quantum cryptographic algorithm families, current standardization efforts, enterprise migration barriers, and strategic readiness measures needed for the quantum computing era. It also discusses the importance of aligning post-quantum migration with existing cybersecurity governance, information systems management, and long-term digital resilience planning. By emphasizing early preparation, structured migration, and continuous cryptographic governance, the article argues that organizations can reduce future quantum-related exposure and strengthen the security of critical digital infrastructure before large-scale quantum attacks become practical (NIST, 2024; NCCoE, 2025).
ABSTRACT Smart cities are built on a vast interconnected network of Internet of things (IoT), edge and cloud systems to optimise urban services and enhance the quality of life for the residents. However, this integration of cyber‐physical infrastructure expands the attack surface, making it vulnerable to advanced cyber threats. The most notable emerging threat is quantum computers, which can break the classical cryptographic algorithms, such as RSA and ECC, that form the foundation of cybersecurity. Integrating liboqs execution benchmarks with an analytical network fragmentation model simulated with NS‐3, evaluating NIST‐approved PQC key encapsulation mechanisms, ML‐KEM (Kyber512/768/1024), HQC (128/192/256) and classic McEliece variants, alongside signature schemes ML‐DSA (Dilithium), Falcon and SLH‐DSA (SPHINCS+) within a smart city network. We also extended the benchmarking to include NIST's SP 800‐230 draft and provide preliminary benchmarks of the six new parameter sets. To assess embedded feasibility, all algorithms are additionally executed on the ESP32 P4 microcontroller, measuring timing, energy consumption and memory under resource‐constrained conditions. This dual platform methodology enables cross‐validation of network‐level overhead and hardware‐level performance. Results show consistent behaviour across platforms. ML KEM 512 (NIST Security Level 1) provides the best KEM performance, with key generation at 7.2 µs (NS‐3) and 122.6 ms (ESP32 P4), and similarly efficient encapsulation/decapsulation. ML DSA 44 (NIST Security Level 2) achieves the fastest signatures at 64 µs on NS‐3 and 490.6 ms on ESP32 P4. These findings provide evidence‐based guidelines for deploying postquantum cryptography across smart city IoT–Edge–Cloud infrastructures, emphasising crypto‐agility and hybrid cryptography for smart city networks.
As quantum computing advances, existing cryptographic techniques used in smart city infrastructures face increasing vulnerability, especially within internet of things (IoT) networks. This chapter explores the critical role of post-quantum cryptography (PQC) in securing urban IoT ecosystems against quantum threats while addressing sustainability challenges. It covers PQC principles, algorithm families, integration with IoT communication protocols, and the protection of critical sectors such as energy, healthcare, and transportation. The chapter also explores quantum-specific network attacks, supply chain vulnerabilities, and the role of green cryptography and AI-assisted security. Emphasis is placed on balancing quantum resilience with energy efficiency to ensure secure, scalable, and sustainable smart cities. The chapter concludes by identifying future research directions to guide the transition toward quantum-safe and eco-conscious urban infrastructure.
The research investigates the implications of quantum computing on smart city infrastructure with a specific focus on addressing cybersecurity challenges. Smart cities, reliant on interconnected systems, are increasingly vulnerable to zero-day attacks exacerbated by quantum computing advancements. This study aims to develop a robust defense framework integrating quantum-resilient cryptographic techniques, artificial intelligence-based anomaly detection systems, and hybrid quantum-classical simulations. The methodology utilizes lattice-based encryption schemes and hash-based signatures to fortify communications, while machine learning models such as Long Short-Term Memory networks and Convolutional Neural Networks identify complex patterns indicative of cyber threats. Evaluation within a simulated smart city environment demonstrates high detection accuracy of 97.8 percent, reduced false positive rates, and efficient resource consumption, validating the framework’s practical applicability. By bridging theoretical advancements and practical implementation, this work enhances the resilience of urban infrastructures against quantum-augmented threats. Findings contribute to the growing body of knowledge by offering scalable and adaptable solutions tailored to the resource-constrained nature of smart cities. Future research can extend this work by addressing energy efficiency, interoperability across sectors, and incorporating federated learning paradigms to enhance distributed anomaly detection. These advancements hold significant implications for securing next-generation urban systems while ensuring sustainability and operational efficiency.