Design And Implementation Of Advanced Secure Boot Loader System On Digital Set-top Box

With the fast development of Internet TV,digital TV is becoming more and more popular.Although the digital life of intelligent broadcasting brings people more convenience,it demands higher security.At present,Most of digital set-top boxes(STB)are based on the embedded systems.The arbitrary code loaded by bootloader(the first boot loader program of embedded system)might be maliciously modified,which will lead to security issues.Driven by the huge profit of digital TV market,the STB's software may suffer from attacks at any time,such as the illegal copies.Therefore,design and implementation of advanced secure bootloader system on digital STB,accord with the market requirement and have practical significance.In this thesis,on the premise of bootloader system demands,combining with advanced secure technology,an advanced secure bootloader system on digital STB is designed and corresponding modules are implemented.These modules contain device driver module,memory management module,upgrade module and advanced secure module.In this thesis,the main contents are as follows:1)learn and master relevant bootloader principles and research cryptography principles which advanced secure technology involves,simultaneously,master data transmission mechanism;2)according to STB users,after analyzing demands and functions of bootloader in detail,compare several common bootloaders to determine bootloader system scheme based on u-boot;3)in the aspect of STB security,after analyzing the demands of advanced secure module,compare the algorithm of symmetric key,one-way hash function and public-key cryptography algorithm to determine the advanced secure scheme which combines the main chip unique identification ID with AES,SHA-256,RSA;4)combine the bootloader system scheme with advanced secure scheme to determine the overall design scheme of advanced secure bootloader system,at the same time,make a division of the whole hierarchical architecture and function modules;5)specifically design and implement the advanced secure bootloader system and its modules;6)test each of the modules in the advanced secure bootloader system to verify the feasibility of the whole system.The test results show that various upgrade methods of the system can work out normally and is secure enough,which meets the requirements.In this thesis,the advanced secure bootloader system scheme is designed in module,It not only has various methods for upgrading,but also is convenient for the extension of function and the transplantation on other platforms later.In addition,the system is suitable for DVB-C,DVB-T,DVB-S and other STB systems and has a certain reference significance for other embedded bootloader system.