Quantitative Information Flow for Scheduler-Dependent Systems
Quantitative Information Flow for Scheduler-Dependent Systems
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DOI：
10.4204/eptcs.194.4
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发表时间：
2015-04
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通讯作者：
Yusuke Kawamoto;Thomas Given-Wilson
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文献类型：
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作者：
Yusuke Kawamoto;Thomas Given-Wilson
定量信息流分析衡量有多少关于秘密的信息被公开可观察的输出所泄露。一个感兴趣的领域是量化和估计组成系统的信息泄漏。先前的工作集中在并行运行不相交的组件系统和推理的泄漏组成，但没有探讨如何组件系统并行运行或如何组成的系统的泄漏可以最小化。在本文中，我们考虑的方式，并行系统可以结合或调度。这考虑了资源可以共享的调度信道的影响，或者是否可以递增地观察输出。我们还概括了攻击者的能力，观察系统的输出，考虑攻击者谁可能是不完善的，在他们的意见，例如，当输出可能会相互混淆，或当评估所需的时间输出出现。我们的主要贡献是如何调度和观察效果的信息泄漏属性。特别是，调度可以隐藏一些泄漏的信息从完美的观察者，而一些调度可能会透露秘密信息，隐藏到不完美的观察者。此外，我们提出了一个算法来构建一个调度器，最小化的最小熵泄漏和最小容量在任何观察员的存在。
Quantitative information flow analyses measure how much information on secrets is leaked by publicly observable outputs. One area of interest is to quantify and estimate the information leakage of composed systems. Prior work has focused on running disjoint component systems in parallel and reasoning about the leakage compositionally, but has not explored how the component systems are run in parallel or how the leakage of composed systems can be minimised. In this paper we consider the manner in which parallel systems can be combined or scheduled. This considers the effects of scheduling channels where resources may be shared, or whether the outputs may be incrementally observed. We also generalise the attacker's capability, of observing outputs of the system, to consider attackers who may be imperfect in their observations, e.g. when outputs may be confused with one another, or when assessing the time taken for an output to appear. Our main contribution is to present how scheduling and observation effect information leakage properties. In particular, that scheduling can hide some leaked information from perfect observers, while some scheduling may reveal secret information that is hidden to imperfect observers. In addition we present an algorithm to construct a scheduler that minimises the min-entropy leakage and min-capacity in the presence of any observer.