Authors: Mohamadou Lamine Diouf ^1,2; Sophie Pinchinat ³

• 1 Université Cheikh Anta Diop [Dakar, Sénégal]
• 2 Université Cheikh Anta Diop de Dakar [Sénégal]
• 3 Logic and Applications

A property (of an object) is opaque to an observer when he or she cannot deduce the property from its set of observations. If each observer is attached to a given set of properties (the so-called secrets), then the system is said to be opaque if each secret is opaque to the corresponding observer. We study in this paper, the complexity of opacity algorithm in data-centric workflows systems. We show that the complexity of this algorithm is EXPTIME-complete. Using the reduction problem, whe show that we can reduce the complexity of opacity problem to wellknow problem, the intersection of nonemptyness problem of Tree automata in polynomial time.