Rewriting-based runtime verification for alternation-free hyperLTL

Abstract

Analysis of complex security and privacy policies (e.g., information flow) involves reasoning about multiple execution traces. This stems from the fact that an external observer may gain knowledge about the system through observing and comparing several executions. Monitoring of such policies is in particular challenging because most existing monitoring techniques are limited to the analysis of a single trace at run time. In this paper, we present a rewriting-based technique for runtime verification of the full alternation-free fragment of HyperLTL, a temporal logic for specification of hyperproperties. The distinguishing feature of our proposed technique is its space complexity, which is independent of the number of trace quantifiers in a given HyperLTL formula.