Weak Behavioral Equivalences for Verifying Secure and Performance-Aware Component-Based Systems

Abstract

Abstract. Component-based systems are characterized by several orthogonal requirements, ranging from security to quality of service, which may demand for the use of opposite strategies and interfering mechanisms. To achieve a balanced tradeoff among these aspects, we have previously proposed the use of a predictive methodology, which encompasses classical tools such as the noninterference approach to security analysis and standard performance evaluation techniques. The former tool, which is based on equivalence checking, is used to reveal functional dependencies among component behaviors, while the latter tool, which relies on reward-based numerical analysis, is used to study the quantitative impact of these dependencies on the system performance. In order to strengthen the relation between these two different analysis techniques we advocate the use of performance-aware notions of behavioral equivalence as a formal means for detecting functional and performance dependencies and then pinpointing the metrics at the base of a balanced tradeoff. Trading Security with PerformanceOne of the major issues in the design of modern computing systems is trading dependability aspects with the expected quality of service [16,10,15]. A balanced tradeoff is particularly hard to accomplish when the dependability aspect of interest is security and the system under analysis requires the interaction of several, possibly untrusted components performing their activities in wide-area, public networks. As an example, it is commonly recognized that lightweight securing infrastructures like those employed for access control in the setting of the IEEE 802.11 standard for wireless local area networks [26] are able to mitigate the impact of the securing mechanisms on quality of service parameters, such as system throughput and response time, still preserving to a specific extent the properties for which they are introduced.Examples such as this emphasize the importance of integrating the different qualitative and quantitative views of a system in order to understand whether a reasonable balance can be achieved between the satisfaction of security requirements and the expected quality of service. However, foundational approaches to the analysis of secure and performance-aware systems have not successfully

Approximate Testing Equivalence Based on Time, Probability, and Observed Behavior

“…With approaches based on pseudometrics it is not easy to establish a clear relation between the measure estimating process similarity and its interpretation in a practical, mainly activity oriented, setting. As an example elucidating this aspect, [3] shows the importance of evaluating the impact that the absence of an equivalence relating two process terms has upon their difference with respect to performability measures. However, this is done without defining explicitly an approximate equivalence relating these measures with the degree of similarity.…”