31,864 research outputs found
PDFS: Practical Data Feed Service for Smart Contracts
Smart contracts are a new paradigm that emerged with the rise of the
blockchain technology. They allow untrusting parties to arrange agreements.
These agreements are encoded as a programming language code and deployed on a
blockchain platform, where all participants execute them and maintain their
state. Smart contracts are promising since they are automated and
decentralized, thus limiting the involvement of third trusted parties, and can
contain monetary transfers. Due to these features, many people believe that
smart contracts will revolutionize the way we think of distributed
applications, information sharing, financial services, and infrastructures.
To release the potential of smart contracts, it is necessary to connect the
contracts with the outside world, such that they can understand and use
information from other infrastructures. For instance, smart contracts would
greatly benefit when they have access to web content. However, there are many
challenges associated with realizing such a system, and despite the existence
of many proposals, no solution is secure, provides easily-parsable data,
introduces small overheads, and is easy to deploy.
In this paper we propose PDFS, a practical system for data feeds that
combines the advantages of the previous schemes and introduces new
functionalities. PDFS extends content providers by including new features for
data transparency and consistency validations. This combination provides
multiple benefits like content which is easy to parse and efficient
authenticity verification without breaking natural trust chains. PDFS keeps
content providers auditable, mitigates their malicious activities (like data
modification or censorship), and allows them to create a new business model. We
show how PDFS is integrated with existing web services, report on a PDFS
implementation and present results from conducted case studies and experiments.Comment: Blockchain; Smart Contracts; Data Authentication; Ethereu
Secure Vehicular Communication Systems: Implementation, Performance, and Research Challenges
Vehicular Communication (VC) systems are on the verge of practical
deployment. Nonetheless, their security and privacy protection is one of the
problems that have been addressed only recently. In order to show the
feasibility of secure VC, certain implementations are required. In [1] we
discuss the design of a VC security system that has emerged as a result of the
European SeVeCom project. In this second paper, we discuss various issues
related to the implementation and deployment aspects of secure VC systems.
Moreover, we provide an outlook on open security research issues that will
arise as VC systems develop from today's simple prototypes to full-fledged
systems
Finite Model Finding for Parameterized Verification
In this paper we investigate to which extent a very simple and natural
"reachability as deducibility" approach, originated in the research in formal
methods in security, is applicable to the automated verification of large
classes of infinite state and parameterized systems. The approach is based on
modeling the reachability between (parameterized) states as deducibility
between suitable encodings of states by formulas of first-order predicate
logic. The verification of a safety property is reduced to a pure logical
problem of finding a countermodel for a first-order formula. The later task is
delegated then to the generic automated finite model building procedures. In
this paper we first establish the relative completeness of the finite
countermodel finding method (FCM) for a class of parameterized linear arrays of
finite automata. The method is shown to be at least as powerful as known
methods based on monotonic abstraction and symbolic backward reachability.
Further, we extend the relative completeness of the approach and show that it
can solve all safety verification problems which can be solved by the
traditional regular model checking.Comment: 17 pages, slightly different version of the paper is submitted to
TACAS 201
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