An Introduction to Physical-layer Security for Wireless Smart Cities

An overview of physical-layer security theory for wireless communication is presented, along with a discussion of the potential feasibility to smart cities and potential future research directions. For a long time security at the physical-layer has been neglected in favour of computational methods implemented at the upper-layers of the protocol stack. Upper-layer cryptography techniques use encryption with a shared-key to achieve secrecy. This security is invariably achieved using cryptographic methods. Current encryption methods are deemed to be secure because the level of computational power required to crack the keys is not attainable using current technology. Nonetheless, the rise of more powerful technologies such as quantum computing may soon challenge this assumption. The computational complexities required to implement public key encryption prevents low-resource devices from using them. This can have a significant impact on wireless systems for Smart Cities which might be limited in terms of available power or computational overhead.