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1 Motivations We propose a tableaux calculus requiring simple exponential time for satissability 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, 1978; Vardi and Wolper, 1986]. However , an algorithm directly derived(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 scenarios of Ambient Intelligence introduce a new computing paradigm and set new challenges for the design and engineering of secure and dependable systems. This chapter describes SERENITY, a comprehensive approach to overcome those problems. The key to success in this scenario is to capture security expertise in such a way that it can be supported by(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)
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)
This paper presents a preexed tableaux calculus for Proposi-tional Dynamic Logic with Converse based on a combination of diierent techniques such as preexed 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)
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)
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)
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)