71,341 research outputs found
Modeling Adversaries in a Logic for Security Protocol Analysis
Logics for security protocol analysis require the formalization of an
adversary model that specifies the capabilities of adversaries. A common model
is the Dolev-Yao model, which considers only adversaries that can compose and
replay messages, and decipher them with known keys. The Dolev-Yao model is a
useful abstraction, but it suffers from some drawbacks: it cannot handle the
adversary knowing protocol-specific information, and it cannot handle
probabilistic notions, such as the adversary attempting to guess the keys. We
show how we can analyze security protocols under different adversary models by
using a logic with a notion of algorithmic knowledge. Roughly speaking,
adversaries are assumed to use algorithms to compute their knowledge; adversary
capabilities are captured by suitable restrictions on the algorithms used. We
show how we can model the standard Dolev-Yao adversary in this setting, and how
we can capture more general capabilities including protocol-specific knowledge
and guesses.Comment: 23 pages. A preliminary version appeared in the proceedings of
FaSec'0
States in Process Calculi
Formal reasoning about distributed algorithms (like Consensus) typically
requires to analyze global states in a traditional state-based style. This is
in contrast to the traditional action-based reasoning of process calculi.
Nevertheless, we use domain-specific variants of the latter, as they are
convenient modeling languages in which the local code of processes can be
programmed explicitly, with the local state information usually managed via
parameter lists of process constants. However, domain-specific process calculi
are often equipped with (unlabeled) reduction semantics, building upon a rich
and convenient notion of structural congruence. Unfortunately, the price for
this convenience is that the analysis is cumbersome: the set of reachable
states is modulo structural congruence, and the processes' state information is
very hard to identify. We extract from congruence classes of reachable states
individual state-informative representatives that we supply with a proper
formal semantics. As a result, we can now freely switch between the process
calculus terms and their representatives, and we can use the stateful
representatives to perform assertional reasoning on process calculus models.Comment: In Proceedings EXPRESS/SOS 2014, arXiv:1408.127
Semantic web service automation with lightweight annotations
Web services, both RESTful and WSDL-based, are an increasingly important part of the Web. With the application of semantic technologies, we can achieve automation of the use of those services. In this paper, we present WSMO-Lite and MicroWSMO, two related lightweight approaches to semantic Web service description, evolved from the WSMO framework. WSMO-Lite uses SAWSDL to annotate WSDL-based services, whereas MicroWSMO uses the hRESTS microformat to annotate RESTful APIs and services. Both frameworks share an ontology for service semantics together with most of automation algorithms
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A linked data compliant framework for dynamic and web-scale consumption of web services
The While Semantic Web Services (SWS) research aims at automating Web service tasks such as discovery, orchestration and execution, its take-up is very limited so far. This is due to several reasons, such as inherent complexity of existing SWS frameworks and the considerable costs involved in creating correct SWS descriptions. In addition, while semantics are in use to enable tasks such as discovery, interaction between service consumers, providers and brokering environments is still not supported by semantic message descriptions. On the other hand, the Linked Data approach has produced a set of established principles for sharing and describing data, such as RDF as representation language and the integral use of dereferencable URIs. In this paper we propose to apply those principles to expose Web services and Web APIs and introduce a framework in which service registries as well as services contribute to the automation of service discovery, and hence, workload is distributed more efficiently. This is achieved by developing a Linked Data compliant Web services framework with that communicate with semi-centralised registries but compute their suitability for a given request themselves. All communications among different framework components are using RDF-based message protocols including service input and output. This framework aims at optimizing load balance and performance by dynamically assembling services at run time in a massively distributed Web environment
Common Knowledge in Email Exchanges
We consider a framework in which a group of agents communicates by means of
emails, with the possibility of replies, forwards and blind carbon copies
(BCC). We study the epistemic consequences of such email exchanges by
introducing an appropriate epistemic language and semantics. This allows us to
find out what agents learn from the emails they receive and to determine when a
group of agents acquires common knowledge of the fact that an email was sent.
We also show that in our framework from the epistemic point of view the BCC
feature of emails cannot be simulated using messages without BCC recipients.Comment: 34 pages. To appear in ACM Transactions on Computational Logi
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