## 3 Research Status Quo  
Many domestic and foreign researchers have put forward corresponding detection and identification methods to resolve network security problems in the Internet of Vehicles.  
This paper applies blockchain technology to the Internet of Vehicles to detect and identify malicious nodes, and solve the problems in the traditional Internet of Vehicles trust model. [PERSON], [PERSON], [PERSON], [PERSON], et al. [1] proposed a method using RFID technology, which is implemented by verifying the vehicle's interactions with the cloud while driving on the road. According to the statistics, the vehicle will use electronic tags to send the data requiring authentication to the cloud storage, and the cloud storage will authenticate the vehicle data after receiving the information, and broadcast the information in the cloud network. [PERSON], [PERSON], et al. [2] proposed a vehicle privacy protection method that combines the certificates issued to a vehicle by a trusted agency and pseudonyms authorized by a trusted agency to build an intelligent privacy authentication system to jointly authenticate a vehicle's identity. However, due to the frequent communication problems in the Internet of vehicles, the certification requirements cannot be met efficiently and in a timely manner. These schemes enable the vehicle to communicate on the road according to the pseudonym produced by the authority, and authenticate the identity of the vehicle through interaction with the RSU. However, these schemes are relatively dependent on the RSU, which leads to the problem of excessive RSU workload [3; 4; 5].  
The application of blockchain in the Internet of Vehicles derives from the following research conclusions. VANET traditional certification and trust detection methods have many problems, which make it difficult to adapt them to the complex networking network environment. Traditional security mechanisms can only deal with a few simple events, cannot store vehicle big data, and struggle with problems regarding queries and traceability. The rise of blockchain technology means that it could be a way to solve the problems with new technology for networking security [6]. [PERSON], [PERSON], et al. [7] propose a certified and secure data transmission algorithm to ensure that real information is communicated between nodes. The authors also introduced blockchain to some of the connected car services to improve efficiency. However, the vehicle needs to be registered at a centralized authority, and the system still has a single-point-of-failure problem. [PERSON], [PERSON], et al. [8] proposed a new blockchain architecture with local, physically verified transactions. With this new architecture, they proposed a protocol that protects vehicle self-organized networks (VANET) that do not regularly communicate with the RSU or other infrastructure components. In addition, they proposed a way to overcome the real-time challenges of applying Bitcoin's blockchain to disconnection by changing the transaction validation mechanism and blockchain management process, and adding a trusted CA.  
In sum, the security risks in the Internet of Vehicles are great, and the harm caused by malicious node attacks cannot be ignored. Existing methods to reduces these risks in the Internet of Vehicles have been effective in their target applications, but they also face several technical challenges, including the need to improve detection accuracy and enhance privacy protection. Some scholars have applied blockchain technology to the Internet of Vehicles to solve these security and trust problems. Blockchain technology leads to decentralization and means that information cannot be tampered with, and the existing blockchain technology is used to detect malicious nodes. However, the accuracy of security messages and the malicious node detection rate need to be further improved. Therefore, the reasonable use of blockchain technology to detect malicious nodes in networks requires further research and exploration [8].