Model Checking Strategic Abilities in Information-sharing Systems
This work addresses the challenge of verifying strategic behaviors in information-sharing systems for security applications, though it appears incremental as it builds on existing concurrent game structures and ATL frameworks.
The paper tackles the problem of model checking strategic abilities in systems with private data-sharing by introducing A-cast systems, a subclass of concurrent game structures with imperfect information, and shows that model checking is decidable for a large fragment of ATL, enabling the encoding of complex security problems like terrorist-fraud attacks.
We introduce a subclass of concurrent game structures (CGS) with imperfect information in which agents are endowed with private data-sharing capabilities. Importantly, our CGSs are such that it is still decidable to model-check these CGSs against a relevant fragment of ATL. These systems can be thought as a generalisation of architectures allowing information forks, in the sense that, in the initial states of the system, we allow information forks from agents outside a given set A to agents inside this A. For this reason, together with the fact that the communication in our models underpins a specialised form of broadcast, we call our formalism A-cast systems. To underline, the fragment of ATL for which we show the model-checking problem to be decidable over A-cast is a large and significant one; it expresses coalitions over agents in any subset of the set A. Indeed, as we show, our systems and this ATL fragments can encode security problems that are notoriously hard to express faithfully: terrorist-fraud attacks in identity schemes.