The use of IoT in the building of Smart cities has transformed how urban areas are managed, as people cannot only monitor in real-time but also automate and make decisions that rely on the data they gather. The post-quantum cryptography (PQC) adoption is a very urgent need as the current classical encryption techniques like RSA and ECC can be broken with quantum computers. The chapter discusses PQC usage in the real world, specifically, in terms of smart urban ecosystems and major areas. It includes real-life case studies of PQC pilotage or proposals in quantum-vulnerable settings to make them more resilient. Moreover, the chapter explains the cryptographic algorithms standardized by NIST, assesses their applicability to constrained IoT use, and proposes a Proof of Concept (PoC) architecture of a PQC-enabled smart city. The chapter is an interim between theory and practice and is a part of the overarching topic of quantum-safe and sustainable urban development, and it provides a practical plan to urban planners, technologists, and cybersecurity professionals.
The use of IoT in the building of Smart cities has transformed how urban areas are managed, as people cannot only monitor in real-time but also automate and make decisions that rely on the data they gather. The post-quantum cryptography (PQC) adoption is a very urgent need as the current classical encryption techniques like RSA and ECC can be broken with quantum computers. The chapter discusses PQC usage in the real world, specifically, in terms of smart urban ecosystems and major areas. It includes real-life case studies of PQC pilotage or proposals in quantum-vulnerable settings to make them more resilient. Moreover, the chapter explains the cryptographic algorithms standardized by NIST, assesses their applicability to constrained IoT use, and proposes a Proof of Concept (PoC) architecture of a PQC-enabled smart city. The chapter is an interim between theory and practice and is a part of the overarching topic of quantum-safe and sustainable urban development, and it provides a practical plan to urban planners, technologists, and cybersecurity professionals.
The development of quantum computing represents an evolutionary change to commonly used forms of public encryption, such as RSA that is designed to protect certain municipal systems which will create further vulnerabilities. Post-quantum cryptography (PQC) can provide a further level of encryption. This chapter discusses how post-quantum techniques can be used to secure the smart infrastructures that support an overall long-range planning process and possibly improve a city's resilience to respond to shocks. This chapter also demonstrates examples from practice, references implications for the original research, and makes recommendations for incorporating quantum resilient cryptography into the urban development agenda through systems thinking.
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 emergence of quantum computing poses significant threats to classical cryptographic systems, particularly in smart urban environments powered by the internet of things (IoT). This chapter explores the sustainability aspects and future prospects of integrating post-quantum cryptography (PQC) into IoT-based infrastructures. It examines various PQC algorithms, their deployment challenges in resource-constrained devices, and the trade-offs between energy efficiency, performance, and security. The chapter also highlights quantum-specific threats, including communication vulnerabilities and supply chain risks, and emphasizes sustainable strategies such as lightweight cryptography, hybrid models, green computing paradigms, and AI-based optimization. Future research directions call for energy-efficient algorithm design, cryptographic hardware co-development, and multidisciplinary collaboration. The study underscores the importance of aligning cryptographic resilience with long-term sustainability goals in smart city systems.
As cities adopt integrated IoT ecosystems and data-driven urban governance, traditional encryption faces the threat of obsolescence by quantum computing attacks. This chapter explores the application of quantum cryptography in protecting smart urban infrastructure, with a focus on quantum key distribution (QKD), post-quantum algorithms, and hybrid systems. Through an examination of deployments in smart grids, traffic management systems, and public health platforms, we illustrate how quantum-resistant protocols reduce threats of data breaches and spoofing attacks. There are special challenges: scaling QKD to millions of IoT devices will need new network architectures, and integrating with legacy systems will need phased “crypto-agility” plans. The chapter presents a model for incorporating quantum-safe practice into urban design, with an emphasis on inter-disciplinary collaboration among cryptographers, policymakers, and city administrators.
Abstract. As the threat of quantum computing to classical cryptography grows, the transition to post-quantum cryptographic (PQC) systems becomes essential—particularly for smart city infrastructures that rely heavily on secure, real-time sensor data. This paper investigates the performance of PQC algorithms currently in the final stages of standardization by the U.S. National Institute of Standards and Technology (NIST), focusing on their deployment in resource-constrained Internet of Things (IoT) devices. Leveraging real-world smart city sensor datasets, we develop a research prototype that simulates a realistic urban sensing scenario, using Raspberry Pi 3 and Pi Zero 2 W devices to cryptographically secure and transmit data to a central server. Experimental results demonstrate that the Kyber family is the most efficient for key encapsulation tasks, while Dilithium and Falcon offer strong performance for digital signatures. In contrast, PQC algorithms such as McEliece, HQC, and Rainbow exhibit substantial computational overhead—especially at higher security levels—limiting their suitability for time-sensitive or low-power environments. Our findings highlight the practical implications of PQC adoption in smart cities and provide evidence-based guidance for selecting efficient quantum-safe algorithms for real-world urban sensor networks.
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.