Compositional and Abstraction-Based Approach for Synthesis of Edit Functions for Opacity Enforcement

TL;DR

This paper introduces a compositional and abstraction-based method for synthesizing edit functions that enforce opacity in modular discrete event systems, reducing computational complexity and ensuring system secrecy.

Contribution

It presents a novel approach combining abstraction techniques and modular synthesis to efficiently enforce opacity in complex systems.

Findings

Reduces computational complexity compared to monolithic methods.

Employs novel abstraction techniques: opaque observation equivalence and opaque bisimulation.

Successfully synthesizes edit functions that guarantee opacity enforcement.

Abstract

This paper develops a novel compositional and abstraction-based approach to synthesize edit functions for opacity enforcement in modular discrete event systems. Edit functions alter the output of the system by erasing or inserting events in order to obfuscate the outside intruder, whose goal is to infer the secrets of the system from its observation. We synthesize edit functions to solve the opacity enforcement problem in a modular setting, which significantly reduces the computational complexity compared with the monolithic approach. Two abstraction methods called opaque observation equivalence and opaque bisimulation are first employed to abstract the individual components of the modular system and their observers. Subsequently, we propose a method to transform the synthesis of edit functions to the calculation of modular supremal nonblocking supervisors. We show that the edit functions synthesized in this manner correctly solve the opacity enforcement problem.