Cyber-physical systems (CPS) are the next generation of intelligent systems that combine the inherent and comprehensive embedding of communication and control technologies to integrate computational resources with hardware facilities. The CPS modules are more vulnerable to an attacker, raising the possibility of physical attacks that might compromise security. For the implementation of lightweight cryptography in CPS, difficulties generally include finding a balance between industrial requirements and publicly available research data. Lightweight cryptographic primitives have a smaller footprint than traditional cryptographic primitives. Lightweight cryptographic techniques are required in the CPS paradigm to minimize latency and resources. Lightweight ciphers' performance advantages include reduced block and key lengths, along with simplified key scheduling. This chapter examines the usage of lightweight cryptography in cyber-physical systems.