Fabio Massacci

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We propose a tableaux calculus requiring simple expo nential time for satis ability of an ALC concept C wrt a TBox T containing general axioms of the form C v D From correspondences with Propositional Dynamic Logic PDL it is known that this problem is in EX PTIME Pratt Vardi and Wolper How ever an algorithm directly derived from the methods used to prove(More)
This paper presents a prefixed tableaux calculus for Propositional Dynamic Logic with Converse based on a combination of different techniques such as prefixed tableaux for modal logics and model checkers for +-calculus. We prove the correctness and completeness of the calculus and illustrate its features. We also discuss the transformation of the tableaux(More)
Autonomic communications seek to improve the ability of network and services to cope with unpredicted change, including changes in topology, load, task, the physical and logical characteristics of the networks that can be accessed, and so forth. Broad-ranging autonomic solutions require designers to account for a range of end-to-end issues affecting(More)
Security Requirements Engineering is emerging as a branch of Software Engineering, spurred by the realization that security must be dealt with early on during the requirements phase. Methodologies in this field are challenging as they must take into account subtle notions such as trust (or lack thereof), delegation, and permission; they must also model(More)
Single Step Tableaux (SST) are the basis of a calculus for modal logics that combines different features of sequent and prefixed tableaux into a simple, modular, strongly analytic, and effective calculus for a wide range of modal logics. The paper presents a number of the computational results about SST (confluence, decidability, space complexity,(More)
Tableau and sequent calculi are the basis for most popular interactive theorem provers for formal veriication. Yet, when it comes to automatic proof search, tableaux are often slower than Davis-Putnam, SAT procedures or other techniques. This is partly due to the absence of a bivalence principle (viz. the cut-rule) but there is another source of ineeciency:(More)
A strong analytic tableau calculus is presentend for the most common normal modal logics. The method combines the advantages of both sequent-like tableaux and preexed tableaux. Proper rules are used, instead of complex closure operations for the accessibility relation, while non deter-minism and cut rules, used by sequent-like tableaux, are totally(More)
The Secure Electronic Transaction (SET) protocol has been proposed by a consortium of credit card companies and software corporations to secure e-commerce transactions. When the customer makes a purchase, the SET dual signature guarantees authenticity while keeping the customer's account details secret from the merchant and his choice of goods secret from(More)
The last years have seen a number of proposals to incorporate Security Engineering into mainstream Software Requirements Engineering. However, capturing trust and security requirements at an organizational level (as opposed to a design level) is still an open problem. This paper presents a formal framework for modeling and analyzing security and trust(More)
Cryptographic algorithms play a key role in computer security and the formal analysis of their robustness is of utmost importance. Yet, logic and automated reasoning tools are seldom used in the analysis of a cipher, and thus one cannot often get the desired formal assurance that the cipher is free from unwanted properties that may weaken its strength. In(More)