Design And Implementation Of Off-line Encryption Programmer Based On M16C64A

Programmer is an indispensable tool of microcomputer development and application. With the continuous expansion of the market, in order to achieve optimal allocation of resources, increasing number of electronic technology companies are committed to the research of product design, and entrust the quantity production to a third-party manufacturer which has large-scale equipment and production line. In this case, data security is inevitably involved to the MCU programming process. To meet the production requirements of Renesas M16C64A series MCU, aiming at the security issues of MCU programming in production process, designed and implemented an off-line encryption programmer based on M16C64A. The fast programming separated from PC on the target MCU is completed by M16C64A standard serial I/O mode. The encrypted storage of program is achieved by combining key addition method with improved Data Encryption Standard. The restriction of off-line programming times is used for improving security Mechanism.Firstly, on the basis of confirming the programmer functional requirements, M16C64A programming principles, Serial Communication Technology, I2C interface technology and DES encryption algorithm are detailedly analyzed. Secondly, according to the system functional requirements, proposed an overall system design scheme. The system hardware part choose R5F364AEDFA of M16C64A series MCU as the central processor, the main portion hardware System includes MCU module, power module, PC communication module, programming interface module, memory module, key module and display module. The system software part includes communication protocol between PC and programmer, MCU control program and host computer software. To ensure the active data communication of both sides, the communication protocol between PC and programmer made a unified provision about data format, synchronous mode, verify mathod and definitions of control characters. The MCU control program realized capabilities of communicating with PC, storing encrypted data, controlling programming times, decrypting data and programming target MCU. The data stored in memory is protected by adding a random number to initial data, and encrypting this number with improved DES, which creats a double encryption method. The host computer software mainly finishes the work of parsing HEX files and communicating with the programmer. To achieve human-computer interaction, designed and completed main interface and function module of the host computer software.Finally, tested the actual application of programmer, including system function test and performance test, and the test results meet expected requests. By comparison of the encrypted data and initial file, verified the successful implementation of encryption storage. And by comparing the time of programming a same time under different programming methods, confirmed that double encryption method balanced the contradiction between data encryption and programming speed. This design has been tested that the programmer can meet the requirements of programming M16C64A series MCU in production process, furthermore, it can limit off-line programming times and encrypt programming files downloaded from PC, which improved the security of data.