Analysis And Design Of Data Transmission Method Based On Vehicle FOTA Terminal

With the development of the automotive industry,the number of vehicle electronic control units is increasing,as well as the probability of functional problems.Automotive OEMs usually use hardware replacement or software updates to resolve functional problems.The traditional large-scale recall for updating softwares has caused huge losses to customers and manufacturers.The emergence of FOTA(Firmware Over The Air)technology can solve this problem well.However,the security and timeliness requirements of automobiles are much higher than other intelligent mobile terminals.Therefore,the current research is focusing on the analysis of ensuring the security and timeliness of the technology.This article mainly analyzes the current status of the vehicle FOTA terminal,presents its current problem of security issues and long transmission time,proposes an optimized data transmission method combininges Bsdiff algorithm and hybrid encryption algorithm in accordance with the FOTA terminal characteristics,and implements the above data transmission method in the vehicle FOTA terminal.The article also designs and builds the vehicle FOTA terminal system platform,finally testes and verified the security and timeliness of the vehicle FOTA terminal on the system platform.The main works of this article are as follows:1.Firstly it introduces the current research status of the vehicle FOTA terminal at home and abroad,analyzes the current long-time data transmission and data transmission security issues of vehicle FOTA terminals,and proposes to ues differential algorithms and encryption algorithms as the key technologies to solve data transmission problems.Besides,the current mainstream differential algorithms and encryption algorithms are compared and analyzed.2.According to the analysis results of the difference algorithm,researches and designs are made based on the Bsdiff algorithm.With a small storage space of ECU(Electronic Control Unit),an optimized Bsdiff algorithm is designed for ECU.Simulation analysis proves that the optimized Bsdiff algorithm shortens the data transmission time of the vehicle FOTA terminal while occupying only a very small part of the ECU storage space.3.According to the analysis results of symmetric encryption algorithm and asymmetric encryption algorithm,a hybrid encryption algorithm that uses AES(Advanced Encryption Standard)algorithm to encrypt plaintext and ECC(Elliptic Curve Cryptography)algorithm to encrypt AES key is designed.Based on the UDS protocol and CAN FD(CAN with Flexible Data rate)message structure,the key exchange and ciphertext sending process between the vehicle FOTA terminal and the ECU are designed.Simulation analysis proves that the hybrid encryption algorithm improves the security of the data transmission process without affecting the performance of the vehicle FOTA terminal.4.Finally,according to the structure of the vehicle FOTA terminal system,the software design of the vehicle FOTA terminal and the ECU is completed,and the basic functions of the vehicle FOTA terminal are realized.Based on this,the optimized Bsdiff algorithm and hybrid encryption algorithm are applied to the vehicle FOTA terminal system,and the overall function and performance are tested.The test results show that in the data transmission method designed in this thesis,the hybrid encryption algorithm enhances the security of data transmission on the vehicle FOTA terminal,and the optimized Bsdiff algorithm improves the timeliness of data transmission.Under the premise of secure transmission,the data compression rate is at least 81% and the highest can reach 94%.The hybrid encryption algorithm increases the time consumption by about 300 ms and the time ratio is less than 3%.Combining the optimized Bsdiff algorithm and the hybrid encryption algorithm,the overall consumption of vehicle FOTA terminal data transmission is reduced by 50%,thus proving the security and timeliness of the data transmission method in this thesis.