Design And Implementation Of Dynamic Trusted System Based On Trusted Chain Transfer

In recent years,embedded systems are increasingly used in many security-critical areas such as aerospace,defense and military.With the development of Internet technology,the embedded system software including personal mobile devices shows explosive growth trend,at the same time security threats from the embedded system or external are increasing,in addition to some conditions about the system security,reliability and other trusted attributes have harsh requirements,the issue for the credibility of the embedded system measurement,transmission and maintenance is imminent.At present,the theory of trusted transmission for system process has become the basis of system credibility judgment.It is of great importance and application value to design and implement a more efficient and stable dynamic trusted transfer system based on the theory of information flow.Based on the theory of information flow and trusted verification,this dissertation studies the key issues of dynamic trusted measurement of system entity process and the construction of dynamic trusted chain in system runtime.The main research contents are as follows: designing a trusted agent module for embedded system and improving a multi-level dynamic trusted measurement model based on information flow.The experimental results show that this model extends the scope of multi-level security access control strategy,which solves the problem of "monotonous defects" in the system trusted level caused by using only mandatory security access control policies and satisfies the intransitive noninterference theory of information flow.According to the problem that existing models verify system dynamic trusted is too strict,this thesis proposes a dynamic intransitive noninterference model based on observable attribute checking,which takes into consideration the change of system state variables into the system security policy.By introducing the iP-Observability attribute,the necessary and sufficient conditions of intransitive noninterference theory is proposed.designed and implemented,and a complete set of system dynamic credibility verification framework Design and implementation of a complete set of system dynamic trusted verification architecture.The experimental results show that this model improves the influence of intransitive noninterference theory on the dynamic change of interference rules during system operation Insufficient problems,to achieve the dynamic verification of the system and with Effectiveness.On the basis of the above work,the thesis realizes each functional module by coding,and designs and initializes a dynamic authentic system verification platform based on the domestic Loongson processor to complete the credibility verification from the start of the system to the end of the process entity.Based on the domestic Godson processor to build an experimental platform and through the design of virtual trusted attack entity process verification model,the experimental results show that the use of dynamic trustworthiness measurement model designed in this thesis and the system dynamic trustworthiness detection mechanism can effectively solve the problem of system trusted maintenance,at the same time,has high efficiency.