  Blockchain has become a key technology in a plethora of application domains
owing to its decentralized public nature. The cyber-physical systems (CPS) is
one of the prominent application domains that leverage blockchain for myriad
operations, where the Internet of Things (IoT) is utilized for data collection.
Although some of the CPS problems can be solved by simply adopting blockchain
for its secure and distributed nature, others require complex considerations
for overcoming blockchain-imposed limitations while maintaining the core aspect
of CPS. Even though a number of studies focus on either the utilization of
blockchains for different CPS applications or the blockchain-enabled security
of CPS, there is no comprehensive survey including both perspectives together.
To fill this gap, we present a comprehensive overview of contemporary
advancement in using blockchain for enhancing different CPS operations as well
as improving CPS security. To the best of our knowledge, this is the first
paper that presents an in-depth review of research on blockchain-enabled CPS
operation and security.
