1,875 research outputs found
Applying Formal Methods to Networking: Theory, Techniques and Applications
Despite its great importance, modern network infrastructure is remarkable for
the lack of rigor in its engineering. The Internet which began as a research
experiment was never designed to handle the users and applications it hosts
today. The lack of formalization of the Internet architecture meant limited
abstractions and modularity, especially for the control and management planes,
thus requiring for every new need a new protocol built from scratch. This led
to an unwieldy ossified Internet architecture resistant to any attempts at
formal verification, and an Internet culture where expediency and pragmatism
are favored over formal correctness. Fortunately, recent work in the space of
clean slate Internet design---especially, the software defined networking (SDN)
paradigm---offers the Internet community another chance to develop the right
kind of architecture and abstractions. This has also led to a great resurgence
in interest of applying formal methods to specification, verification, and
synthesis of networking protocols and applications. In this paper, we present a
self-contained tutorial of the formidable amount of work that has been done in
formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial
Efficient First-Order Temporal Logic for Infinite-State Systems
In this paper we consider the specification and verification of
infinite-state systems using temporal logic. In particular, we describe
parameterised systems using a new variety of first-order temporal logic that is
both powerful enough for this form of specification and tractable enough for
practical deductive verification. Importantly, the power of the temporal
language allows us to describe (and verify) asynchronous systems, communication
delays and more complex properties such as liveness and fairness properties.
These aspects appear difficult for many other approaches to infinite-state
verification.Comment: 16 pages, 2 figure
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
Aximo: automated axiomatic reasoning for information update
Aximo is a software written in C++ that verifies epistemic properties of dynamic scenarios in multi-agent systems. The underlying logic of our tool is based on the algebraic axiomatics of Dynamic Epistemic Logic. We also present a new theoretical result: the worst case complexity of the verification problem of Aximo
Towards the Verification of Pervasive Systems
Pervasive systems, that is roughly speaking systems that can interact with their environment, are increasingly common. In such systems, there are many dimensions to assess: security and reliability, safety and liveness, real-time response, etc. So far modelling and formalizing attempts have been very piecemeal approaches. This paper describes our analysis of a pervasive case study (MATCH, a homecare application) and our proposal for formal (particularly verification) approaches. Our goal is to see to what extent current state of the art formal methods are capable of coping with the verification demand introduced by pervasive systems, and to point out their limitations
Tool support for reasoning in display calculi
We present a tool for reasoning in and about propositional sequent calculi.
One aim is to support reasoning in calculi that contain a hundred rules or
more, so that even relatively small pen and paper derivations become tedious
and error prone. As an example, we implement the display calculus D.EAK of
dynamic epistemic logic. Second, we provide embeddings of the calculus in the
theorem prover Isabelle for formalising proofs about D.EAK. As a case study we
show that the solution of the muddy children puzzle is derivable for any number
of muddy children. Third, there is a set of meta-tools, that allows us to adapt
the tool for a wide variety of user defined calculi
Modal tableaux for verifying stream authentication protocols
To develop theories to specify and reason about various aspects of multi-agent systems, many researchers have proposed the use of modal logics such as belief logics, logics of knowledge, and logics of norms. As multi-agent systems operate in dynamic environments, there is also a need to model the evolution of multi-agent systems through time. In order to introduce a temporal dimension to a belief logic, we combine it with a linear-time temporal logic using a powerful technique called fibring for combining logics. We describe a labelled modal tableaux system for the resulting fibred belief logic (FL) which can be used to automatically verify correctness of inter-agent stream authentication protocols. With the resulting fibred belief logic and its associated modal tableaux, one is able to build theories of trust for the description of, and reasoning about, multi-agent systems operating in dynamic environments
A standard-driven communication protocol for disconnected clinics in rural areas
The importance of the Electronic Health Record (EHR), which stores all healthcare-related data belonging to a patient, has been recognized in recent years by governments, institutions, and industry. Initiatives like Integrating the Healthcare Enterprise (IHE) have been developed for the definition of standard methodologies for secure and interoperable EHR exchanges among clinics and hospitals. Using the requisites specified by these initiatives, many large-scale projects have been set up to enable healthcare professionals to handle patients' EHRs. Applications deployed in these settings are often considered safety-critical, thus ensuring such security properties as confidentiality, authentication, and authorization is crucial for their success. In this paper, we propose a communication protocol, based on the IHE specifications, for authenticating healthcare professionals and assuring patients' safety in settings where no network connection is available, such as in rural areas of some developing countries. We define a specific threat model, driven by the experience of use cases covered by international projects, and prove that an intruder cannot cause damages to the safety of patients and their data by performing any of the attacks falling within this threat model. To demonstrate the feasibility and effectiveness of our protocol, we have fully implemented it
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