Key Technology Research Of Trusted Computing Environment For Embedded System

At present, the rapid development of electronic and information technology, making embedded computer technology to a wide range of popular applications, embedded devices has become a national defense, medical, industrial process control, financial, and even in people’s lives, one of the components are inseparable. These embedded devices provide a convenient time for the human society of its own credibility but also draw attention to how the characteristics of embedded systems, to build a highly trusted embedded computing environment has become a hot research field of information security one.Existing computing systems to build a trusted environment technology is mainly focused on the desktop and server space, it is difficult for embedded fields. In addition, existing techniques for software reliability analysis system state is not credible to consider the impact of software entities. Based on dual-core technology, the flow of information without interference, non-transfer theory, the key issue for the embedded trusted environment to build a trusted root design, credible analysis, credible chain of transmission, remote proof to carry out in-depth research.Innovative research results are:(1) Dual-core architecture based on, and put forward a method to construct the embedded software trusted root consisting of Bootloader and trusted kernel, curing in the guide FLASH Bootloader measurement and load the trusted kernel, trusted kernel by banning the user kernel and application of FLASH write access, to realize the protection of Bootloader; trusted kernel embedded virtual TPM(v TPM) module, implementation and provide cryptography related functions and service for the user kernel, guide the specific area development in FLASH for PCR registers required to achieve a v TPM and related storage area. Compared with the TCG trusted computing architecture, this method does not require additional hardware, and is suitable for the existing majority of embedded processors, to avoid an increase in cost, power consumption, volume. Prototype verification results show that, the root of trust model to achieve the TPM cryptographic functions, and can resist to the software(non physical) attack.(2) Dual-core architecture based on, put forward a kind of rod- branch type chain of trust transfer model, from the trusted root to the operating system, the use of chain chain of trust transfer model, from the operating system to the application using the star type chain of trust transfer model. Rod-branch type model, operating system kernel as key trusted system component metrics directly by the trusted root, known as the main rod chain of trust, the application which is measured by the trusted operating system kernel embedded v TPM, called the trust chain branching, this model effectively reduced the trusted chain length, not only to avoid the chain transfer with the trust attenuation problem, but also improves the problem of low efficiency in all the trust by all the ETPM measurement caused by the star type model.(3) Proposed a dynamic non transitive information flow software dynamic trusted non interference model analysis method based on the system state, discusses the influence of the software dependability, using access control describe software entity operating state interference behavior, establish the analysis model, provides a new method the theory support for the trust chain transfer analysis software dynamic trusted process. Based on the judgment theorem is given system is credible, and proved, provides the technology analysis of trusted chain affects the system state transfer process of software trustworthiness problem.(4) For the two binary hash tree root hash updates dynamically constructed low efficiency problem, proposes a new data structure- full left hash tree, and presents a new leaf node insertion algorithm and root hash update algorithm, compared with the balance of the two fork hash tree, can greatly reduce the new leaf nodes insertion brought Ganhashi update computation, construction time and can effectively reduce the hash tree.(5) Presents a proven model of dynamic trusted remote concern based on the points, gives a formal definition of remote attestation, analyzes the relationship between consultant and proof in the proof of the remote party, discusses the rationality of Remote Attestation Based on concerns, by the trusted root and application of dynamic trusted monitor module combination, will measurement prove into the basic computing environment, the application of dynamic trusted monitor module, request service module concerns metrics demonstrate for all loading modules in IMA; use metric full left hash tree to store application integrity value, both to protect the certificate other application modules of privacy, but also improves the efficiency of proof. Data experimental prototype system shows that the system can dynamically verify program behavior, to make up for the lack of static measurement, and has less impact on system performance.