Model-checking Strategic Abilities in Information-sharing Systems

Francesco Belardinelli, Ioana Boureanu, Catalin Dima, Vadim Malvone

Abstract: 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 generalization of architectures allowing information forks, that is, cases where strategic abilities lead to certain agents outside a coalition privately sharing information with selected agents inside that coalition. Moreover, in our case, in the initial states of the system, we allow information forks from agents outside a given set \(A\) to agents inside this group \(A\). For this reason, together with the fact that the communication in our models underpins a specialized 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.

External IDs:dblp:journals/tocl/BelardinelliBDM25