Security protocols stipulate how the remote principals of a computer network should interact in order to obtain specific security goals. The crucial goals of confidentiality and authentication may be achieved in vario...
详细信息
Security protocols stipulate how the remote principals of a computer network should interact in order to obtain specific security goals. The crucial goals of confidentiality and authentication may be achieved in various forms, each of different strength. Using soft (rather than crisp) constraints, we develop a uniform formal notion for the two goals. They are no longer formalised as mere yes/no properties as in the existing literature, but gain an extra parameter, the security level. For example, different messages can enjoy different levels of confidentiality, or a principal can achieve different levels of authentication with different principals. The goals are formalised within a general framework for protocol analysis that is amenable to mechanisation by model checking. Following the application of the framework to analysing the asymmetric Needham-Schroeder protocol (Bella and Bistarelli 2001;Bella and Bistarelli 2002), we have recently discovered a new attack on that protocol as a form of retaliation by principals who have been attacked previously. Having commented on that attack, we then demonstrate the framework on a bigger, largely deployed protocol consisting of three phases, Kerberos.
The ability of providing and relating temporal representations at different 'grain levels' of the same reality is an important research theme in computer science and a major requirement for many applications, ...
详细信息
The ability of providing and relating temporal representations at different 'grain levels' of the same reality is an important research theme in computer science and a major requirement for many applications, including formal specification and verification, temporal databases, data mining, problem solving, and natural language understanding. In particular, the addition of a granularity dimension to a temporal logic makes it possible to specify in a concise way reactive systems whose behaviour can be naturally modeled with respect to a (possibly infinite) set of differently-grained temporal domains. Suitable extensions of the monadic second-order theory of k successors have been proposed in the literature to capture the notion of time granularity. In this paper, we provide the monadic second-order theories of downward unbounded layered structures, which are infinitely refinable structures consisting of a coarsest domain and an infinite number of finer and finer domains, and of upward unbounded layered structures, which consist of a finest domain and an infinite number of coarser and coarser domains, with expressively complete and elementarily decidable temporal logic counterparts. We obtain such a result in two steps. First, we define a new class of combined automata, called temporalized automata, which can be proved to be the automata-theoretic counterpart of temporalized logics, and show that relevant properties, such as closure under Boolean operations, decidability, and expressive equivalence with respect to temporal logics, transfer from component automata to temporalized ones. Then, we exploit the correspondence between temporalized logics and automata to reduce the task of finding the temporal logic counterparts of the given theories of time granularity to the easier one of finding temporalized automata counterparts of them.
Security protocols stipulate how the remote principals of a computer network should interact in order to obtain specific security goals. The crucial goals of confidentiality and authentication may be achieved in vario...
详细信息
Security protocols stipulate how the remote principals of a computer network should interact in order to obtain specific security goals. The crucial goals of confidentiality and authentication may be achieved in various forms, each of different strength. Using soft (rather than crisp) constraints, we develop a uniform formal notion for the two goals. They are no longer formalised as mere yes/no properties as in the existing literature, but gain an extra parameter, the security level. For example, different messages can enjoy different levels of confidentiality, or a principal can achieve different levels of authentication with different principals. The goals are formalised within a general framework for protocol analysis that is amenable to mechanisation by model checking. Following the application of the framework to analysing the asymmetric Needham-Schroeder protocol (Bella and Bistarelli 2001;Bella and Bistarelli 2002), we have recently discovered a new attack on that protocol as a form of retaliation by principals who have been attacked previously. Having commented on that attack, we then demonstrate the framework on a bigger, largely deployed protocol consisting of three phases, Kerberos.
Declarative multi-paradigm languages combine the main features of functional and logicprogramming, like laziness, logic variables and non-determinism. The operational semantics of these languages is based on a combin...
详细信息
The proceedings contain 28 papers. The special focus in this conference is on programming Languages and Systems. The topics include: Resources, concurrency, and local reasoning;relational abstract domains for the dete...
ISBN:
(纸本)3540213139
The proceedings contain 28 papers. The special focus in this conference is on programming Languages and Systems. The topics include: Resources, concurrency, and local reasoning;relational abstract domains for the detection of floating-point run-time errors;strong preservation as completeness in abstract interpretation;static analysis of digital filters;sound and decidable type inference for functional dependencies;ML-like inference for classifiers;from constraints to finite automata to filtering algorithms;a memoizing semantics for functional logic languages;adaptive pattern matching on binary data;compositional analysis of authentication protocols;a distributed abstract machine for boxed ambient calculi;a dependently typed ambient calculus;a control flow analysis for safe and boxed ambients;linear types for packet processing;modal proofs as distributed programs;a core programming model for global computing;a semantic framework for designer transactions;answer type polymorphism in call-by-name continuation passing;expansion variables for flexible typing with linear and non-linear types and intersection types;a hardest attacker for leaking references;a rely-guarantee method;just fast keying in the pi calculus;decidable analysis of cryptographic protocols with products and modular exponentiation;functors for proofs and programs;extracting a data flow analyser in constructive logic and canonical graph shapes.
This paper describes in detail how to bridge the gap between theory and practice in a new implementation of the CCS operational semantics in Maude, where transitions become rewrites and inference rules become conditio...
详细信息
We are presenting a semantic analysis of Reynolds’s specification logic of Idealized Algol using the parametric operational techniques developed by Pitts. We hope that this more elementary account will make the insig...
详细信息
Pricing policy is a sensitive and critical issue in today's competitive and dynamic market environment. This is especially true in the analysis of price structure in a supply chain where uncertainty in many factor...
详细信息
Pricing policy is a sensitive and critical issue in today's competitive and dynamic market environment. This is especially true in the analysis of price structure in a supply chain where uncertainty in many factors can have a profound effect on the supply chain performance. In this paper, we propose a novel approach to determine the price in a supply chain model in which several uncertain factors such as cost, inventory level, and competitors' prices have been considered. The objective here is to seek a coordinating, flexible pricing policy under uncertainty to maximize profit while meeting customer demand. As a result, artificial intelligence tools such as fuzzy logic have been applied to determine the price and the demand. A mathematical programming model has been used to find the optimal profit. Results showed that the dynamic pricing policy under uncertainty is an effective way to coordinate the price and supply chain channel and to improve the profit of the overall system. Fuzzy inferencing and mathematical modeling provided an efficient solution to the problem.
暂无评论