性能问题是阻碍DAA推广和应用的首要问题.为了进一步优化该协议的性能,找出性能瓶颈,定量地分析和测量DAA中各个实体的性能负荷分布是一个十分重要且必须的工作.文中详细分析了DAA的协议流程,提出了以机器周期为基本性能单位的性能负荷分布测量方法——归一化统计法(Normalized Statistics,NS).该方法需要首先分析DAA协议中的各种复杂运算,针对不同的运算选用当前性能较好的算法,然后统计各个算法中大整数单精度乘法、单精度加法、读内存、写内存等基本运算的数目,最后通过汇总并转换得出DAA协议中各实体以机器周期为单位的性能负荷分布和总性能负荷.比较分析表明,该方法不仅能相对准确、精细、有效地定量计算出DAA协议中各实体的性能负荷和总的性能负荷,而且测出的性能负荷具有平台无关性.最后为了说明该方法的有效性,将NS方法应用于有关可信计算匿名证明的一个典型方案的性能负荷估算.
Performance is a most important problem to Direct Anonymous Attestation Scheme in TCG.It is very necessary and important to analyze and measure performance to every entity quantitatively for optimizing DAA.In this paper,DAA protocol is first analysed detailedly,and then a new performance measurement method,called Normalized Statistics method,which takes the machine period as the basic performance unit,is put forward.When using this method,all complex calculates in DAA protocol must be found out and statistic,and better algorithms to every complex calculate are chosen,moreover,to each algorithms,we need to compute the sum for each basic operation,such as multiplication of single big integer,addition of single big integer,reading and writing memory,and so on.Finally,the every entity performance and the whole performance burden in DAA,whose unit is the machine period,are summed.The theoretical analysis results show that the performance estimate is exact,meticulous and effective by this method which is independent of actual platform.For proving availability of the method,we apply it to estimate performance of other one DAA scheme.