入侵容忍系统安全属性分析

首先提出一个优化的系统状态转移模型，用以描述具有自我演进能力的入侵容忍系统的动态行为，并提高了对攻击行为的描述能力，以该模型为基础，建立SMP模型并对系统安全属性及可执行性进行定量分析，进而计算出系统平均安全故障时间（MTTSF）；最后给出数值分析结果，并通过计算模型中时间参数的敏感度，得出入侵容忍技术研究的关键点．

Security Attributes Analysis for Intrusion Tolerant Systems

It is significant to analyze security attributes of intrusion tolerant system while we research the effects of intrusion tolerance technologies. The paper puts forward an optimized states transition model to characterize dynamic actions of the intrusion tolerant systems with self-evolutional capability. The model improves the capability to describe attack actions and characterizes the modality of systems efficiently. The authors build a semi Markov process based on the embedded Markov chain of the states transition model. Security attributes including availability and confidentiality and integrality are analyzed by computing steady states probability of Markov model. Associating a reward rate with every state of the model, performability of the system is also computed quantitatively. The mean time to security failure MTTSF is calculated afterwards by computing the visit counts and mean sojourn times of non-absorbing states in SMP model. Finally, numerical results are presented and sensitivity analysis of time parameters in the model is reckoned in order to educe the key research points of intrusion tolerance technology.