Cyber-physical systems (CPS) may be targeted by multiple simultaneous attacks, with the goal of disrupting availability, safety, and performance of the CPS.  This project aims to develop a passivity-based framework for modeling, composing, and mitigating attacks on CPS, as well as verifying the models and mitigation.  Passivity is an energy dissipation property of dynamical systems that provides basic rules for composition and analysis of interconnected systems.