  Cyber-physical systems and the Internet of things (IoT) is becoming an
integral part of the digital society. The use of IoT services improves human
life in many ways. Protection against cyber threats is an important aspect of
the functioning of IoT devices. Malicious activities lead to confidential data
leakages and incorrect performance of devices are becoming critical. Therefore,
development of effective solutions that can protect both IoT devices data and
data exchange networks turns in to a real challenge. This study provides a
critical analysis of the feasibility of using blockchain technology to protect
constrained IoT devices data, justifies the choice of Practical Byzantine Fault
Tolerance (PBFT) consensus algorithm for implementation on such devices, and
simulates the main distributed ledger scenarios using PBFT. The simulation
results demonstrate the efficiency of the blockchain technology for constrained
devices and make it possible to evaluate the applicability limits of the chosen
consensus algorithm.
