Runtime Monitoring of Metric First-order Temporal Properties

We introduce a novel approach to the runtime monitoring of complex system properties. In particular, we present an online algorithm for a safety fragment of metric first-order temporal logic that is considerably more expressive than the logics supported by prior monitoring methods. Our approach, based on automatic structures, allows the unrestricted use of negation, universal and existential quantification over infinite domains, and the arbitrary nesting of both past and bounded future operators. Moreover, we show how to optimize our approach for the common case where structures consist of only finite relations, over possibly infinite domains. Under an additional restriction, we prove that the space consumed by our monitor is polynomially bounded by the cardinality of the data appearing in the processed prefix of the temporal structure being monitored

Intransitive non-interference for cryptographic purposes. In

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Composable Security Analysis of OS Services

We provide an analytical framework for analyzing basic integrity properties of file systems, namely the binding of files to filenames and writing capabilities. A salient feature of our modeling and analysis is that it is *composable*: In spite of the fact that we analyze the filesystem in isolation, security is guaranteed even when the file system operates as a component within an arbitrary, and potentially adversarial system. Such secure composability properties seem essential when trying to assert the security of large systems. Our results are obtained by adapting the *Universally Composable* (UC) security framework to the analysis of software systems. Originally developed for cryptographic protocols, the UC framework allows the analysis of simple components in isolation, and provides assurance that these components maintain their behavior when combined in a large system, potentially under adversarial conditions