  The Internet of Vehicles (IoV) is an application of the Internet of things
(IoT). It faces two main security problems: (1) the central server of the IoV
may not be powerful enough to support the centralized authentication of the
rapidly increasing connected vehicles, (2) the IoV itself may not be robust
enough to single-node attacks. To solve these problems, this paper proposes
SG-PBFT: a secure and highly efficient PBFT consensus algorithm for Internet of
Vehicles, which is based on a distributed blockchain structure. The distributed
structure can reduce the pressure on the central server and decrease the risk
of single-node attacks. The SG-PBFT consensus algorithm improves the
traditional PBFT consensus algorithm by using a score grouping mechanism to
achieve a higher consensus efficiency. The experimental result shows that our
method can greatly improve the consensus efficiency and prevent single-node
attacks. Specifically, when the number of consensus nodes reaches 1000, the
consensus time of our algorithm is only about 27% of what is required for the
state-of-the-art consensus algorithm (PBFT). Our proposed SG-PBFT is versatile
and can be used in other application scenarios which require high consensus
efficiency.
