  Smart city architecture brings all the underlying architectures, i.e.,
Internet of Things (IoT), Cyber-Physical Systems (CPSs), Internet of
Cyber-Physical Things (IoCPT), and Internet of Everything (IoE), together to
work as a system under its umbrella. The goal of smart city architecture is to
come up with a solution that may integrate all the real-time response
applications. However, the cyber-physical space poses threats that can
jeopardize the working of a smart city where all the data belonging to people,
systems, and processes will be at risk. Various architectures based on
centralized and distributed mechanisms support smart cities; however, the
security concerns regarding traceability, scalability, security services,
platform assistance, and resource management persist. In this paper, private
blockchain-based architecture Decentralized Smart City of Things (DSCoT) is
proposed. It actively utilizes fog computing for all the users and smart
devices connected to a fog node in a particular management system in a smart
city, i.e., a smart house or hospital, etc. Non-fungible tokens (NFTs) have
been utilized for representation to define smart device attributes. NFTs in the
proposed DSCoT architecture provide devices and user authentication (IoT)
functionality. DSCoT has been designed to provide a smart city solution that
ensures robust security features such as Confidentiality, Integrity,
Availability (CIA), and authorization by defining new attributes and functions
for Owner, User, Fog, and IoT devices authentication. The evaluation of the
proposed functions and components in terms of Gas consumption and time
complexity has shown promising results. Comparatively, the Gas consumption for
minting DSCoT NFT showed approximately 27%, and a DSCoT approve() was
approximately 11% more efficient than the PUF-based NFT solution.
