  With the development of intelligent transportation systems, vehicles are
exposed to a complex network environment. As the main network of in-vehicle
networks, the controller area network (CAN) has many potential security
hazards, resulting in higher requirements for intrusion detection systems to
ensure safety. Among intrusion detection technologies, methods based on deep
learning work best without prior expert knowledge. However, they all have a
large model size and rely on cloud computing, and are therefore not suitable to
be installed on the in-vehicle network. Therefore, we propose a lightweight
parallel neural network structure, LiPar, to allocate task loads to multiple
electronic control units (ECU). The LiPar model consists of multi-dimensional
branch convolution networks, spatial and temporal feature fusion learning, and
a resource adaptation algorithm. Through experiments, we prove that LiPar has
great detection performance, running efficiency, and lightweight model size,
which can be well adapted to the in-vehicle environment practically and protect
the in-vehicle CAN bus security.
