Design Of Passive Keyless Entry And AES Algorithm In Dynamic Key Mechanism

With the development of automobile technology, automobile device more and more tend to use wireless control and passive control. Passive Keyless Entry(PKE) technology emerge as the times require, PKE is an interactive system based on two-way communication, it is the first generation product of Remote Keyless Entry(RKE) based unidirectional radio frequency communication on intelligent upgrade. As one of the research focus in recent years in automotive electronics, it will lead the auto culture to the intelligent and humane direction. This technology will become the standard car future allocation. This paper analysis and research the trend of PKE development and situation at home and abroad, found the foreign have relatively leading research plan and technical products. A few large semiconductor chip vendors such as MICROCHIP, TI, Atmel, Freescale, NXP and other companies have put forward its own design for this system. And because of technology security and development cost, the domestic automobile industry on the development of this system is still not perfect. Only BYD car companies have a few high-end models for assembling this system, while the JAC and Chery automobile company is only part of the model fitting the system. So the independent research and design of the system is the problem which needed to solve.Then it present the Architecture of hardware and software of each function module in PKE system. And it analysis the key technologies of the system in detail, including the PWM modulation, Manchester’s coding, Security encryption algorithm, and authentication system. Concluding that the security of PKE is mainly by the RF communication security encryption algorithm, the KEELOQ algorithm and the Advanced Encryption Standard (AES) algorithm which are the mainstream of the market is compared and analyzed, According to the rolling code and synchronous window mechanism of KEELOQ algorithm and the high security of AES algorithm with the anti attack capability, this paper proposes a AES algorithm based on dynamic key mechanism and gives the frame format of low frequency and RF, as well as the function of the system and the communication process of function modules. This design is based on the AVR series Single chip microcomputer of Atmel, the system realizes the function of data transmission with low power consumption and high efficiency. The reliability of the system can be guaranteed at the same time, redesign and definition of identity authentication protocol in the RF communication system, using the MD5 hash function to the dynamic update of fixed initial key in the AES algorithm, which can effectively make up for deficiencies and shortcomings existing fixed key exposure threats in the traditional protocol. A updating key mechanism, introduce the mechanism of synchronous window and check code error correction and the use of dual authentication, improving the safety performance of the whole system.Finally, system’s functions are proofed under the QT environment and by using Atmel Corp software it shows the entire system UI. Testing and analysis the system’s power consumption and the AES algorithm in dynamic key mechanism, showing that the AES key improvements proposed safe and effective, system designed in key performance areas such as power consumption and reliability can meet the basic requirements.