Abstract

The rapid development of smart cities relies heavily on the Internet of Things (IoT) to enhance urban infrastructure, optimize resource management, and improve citizens' quality of life. However, the increasing interconnectivity of IoT devices raises significant security concerns, including unauthorized access, data breaches, and cyberattacks. Cryptographic techniques play a crucial role in securing IoT communication by ensuring data confidentiality, integrity, and authentication. This chapter explores the application of modern cryptographic solutions such as lightweight encryption algorithms, blockchain-based security models, and post-quantum cryptography in IoT networks. It also discusses key challenges, including computational constraints of IoT devices, scalability, and interoperability, while highlighting potential future research directions for enhancing cryptographic security in smart city IoT infrastructures.