IP多媒体子系统(IP multimedia subsystem,IMS)作为网络与业务融合的标准将会在三网融合中扮演重要的角色,因此研究其认证注册过程的可生存性具有重要意义.文中首先给出可生存性概念与评价指标以及I.MS的认证注册过程,然后建立相应的随机Petri网(stochastic Petri net,SPN)模型和简化的可生存性SPN模型,并给出可生存性的主要指标——可靠性、可维护性及可用性.对所建模型的可靠性及可维护性评价指标进行了仿真,表明可靠性分别随时间及失效率的增加而显著降低,可维护性随时间及修复率的增加而明显增强并最终趋于稳定.这些结论为增强IMS系统可生存性能力提供了有效的数值参考依据.
One important function in trusted computing is protected storage, which can protect unlimited amount of data and keys. In the existing trusted platform module （TPM） key loading scheme for trusted platform, a computing platform with TPM as its trusted anchor, the total times of loading operation is the same as the number of the loaded target object＇s ancestors, resulting in low efficiency of loading a TPM key which has many ancestors. To improve efficiency, an identity-based TPM key loading scheme is proposed. In this scheme, the times of loading operation is only two when any TPM key is loaded into TPM. Therefore, the required time cost for loading a TPM key can be reduced, especially for complex TPM key storage hierarchy. By analyzing the correctness, security, efficiency and feasibility, the proposed scheme has the better theoretical and application value.
SONG ChengLIU BingHU Zheng-mingXIN YangYANG Yi-xianYIN Han
