Early Verification of Legal Compliance via Bounded Satisfiability Checking

TL;DR

This paper introduces a bounded satisfiability checking method for MFOTL to verify legal compliance early in system development, using SMT solving and counterexample-guided search.

Contribution

It presents a practical, sound, and complete (within bounds) approach for MFOTL satisfiability checking, filling a gap in early-stage legal property verification.

Findings

Efficiently determines legal property compliance or violations

Implemented with Z3 SMT solver and tested on diverse case studies

Provides counterexamples for non-compliance scenarios

Abstract

Legal properties involve reasoning about data values and time. Metric first-order temporal logic (MFOTL) provides a rich formalism for specifying legal properties. While MFOTL has been successfully used for verifying legal properties over operational systems via runtime monitoring, no solution exists for MFOTL-based verification in early-stage system development captured by requirements. Given a legal property and system requirements, both formalized in MFOTL, the compliance of the property can be verified on the requirements via satisfiability checking. In this paper, we propose a practical, sound, and complete (within a given bound) satisfiability checking approach for MFOTL. The approach, based on satisfiability modulo theories (SMT), employs a counterexample-guided strategy to incrementally search for a satisfying solution. We implemented our approach using the Z3 SMT solver and evaluated it on five case studies spanning the healthcare, business administration, banking and aviation domains. Our results indicate that our approach can efficiently determine whether legal properties of interest are met, or generate counterexamples that lead to compliance violations.