3,184 research outputs found
Timed Analysis of Security Protocols
We propose a method for engineering security protocols that are aware of
timing aspects. We study a simplified version of the well-known Needham
Schroeder protocol and the complete Yahalom protocol, where timing information
allows the study of different attack scenarios. We model check the protocols
using UPPAAL. Further, a taxonomy is obtained by studying and categorising
protocols from the well known Clark Jacob library and the Security Protocol
Open Repository (SPORE) library. Finally, we present some new challenges and
threats that arise when considering time in the analysis, by providing a novel
protocol that uses time challenges and exposing a timing attack over an
implementation of an existing security protocol
Options for Securing RTP Sessions
The Real-time Transport Protocol (RTP) is used in a large number of
different application domains and environments. This heterogeneity
implies that different security mechanisms are needed to provide
services such as confidentiality, integrity, and source
authentication of RTP and RTP Control Protocol (RTCP) packets
suitable for the various environments. The range of solutions makes
it difficult for RTP-based application developers to pick the most
suitable mechanism. This document provides an overview of a number
of security solutions for RTP and gives guidance for developers on
how to choose the appropriate security mechanism
On Non-Parallelizable Deterministic Client Puzzle Scheme with Batch Verification Modes
A (computational) client puzzle scheme enables a client to prove to a server that a certain amount of computing resources (CPU cycles and/or Memory look-ups) has been dedicated to solve a puzzle. Researchers have identified a number of potential applications, such as constructing timed cryptography, fighting junk emails, and protecting critical infrastructure from DoS attacks. In this paper, we first revisit this concept and formally define two properties, namely deterministic computation and parallel computation resistance. Our analysis show that both properties are crucial for the effectiveness of client puzzle schemes in most application scenarios. We prove that the RSW client puzzle scheme, which is based on the repeated squaring technique, achieves both properties. Secondly, we introduce two batch verification modes for the RSW client puzzle scheme in order to improve the verification efficiency of the server, and investigate three methods for handling errors in batch verifications. Lastly, we show that client puzzle schemes can be integrated with reputation systems to further improve the effectiveness in practice
Oblivion: Mitigating Privacy Leaks by Controlling the Discoverability of Online Information
Search engines are the prevalently used tools to collect information about
individuals on the Internet. Search results typically comprise a variety of
sources that contain personal information -- either intentionally released by
the person herself, or unintentionally leaked or published by third parties,
often with detrimental effects on the individual's privacy. To grant
individuals the ability to regain control over their disseminated personal
information, the European Court of Justice recently ruled that EU citizens have
a right to be forgotten in the sense that indexing systems, must offer them
technical means to request removal of links from search results that point to
sources violating their data protection rights. As of now, these technical
means consist of a web form that requires a user to manually identify all
relevant links upfront and to insert them into the web form, followed by a
manual evaluation by employees of the indexing system to assess if the request
is eligible and lawful.
We propose a universal framework Oblivion to support the automation of the
right to be forgotten in a scalable, provable and privacy-preserving manner.
First, Oblivion enables a user to automatically find and tag her disseminated
personal information using natural language processing and image recognition
techniques and file a request in a privacy-preserving manner. Second, Oblivion
provides indexing systems with an automated and provable eligibility mechanism,
asserting that the author of a request is indeed affected by an online
resource. The automated ligibility proof ensures censorship-resistance so that
only legitimately affected individuals can request the removal of corresponding
links from search results. We have conducted comprehensive evaluations, showing
that Oblivion is capable of handling 278 removal requests per second, and is
hence suitable for large-scale deployment
Specification and Verification of Context-dependent Services
Current approaches for the discovery, specification, and provision of
services ignore the relationship between the service contract and the
conditions in which the service can guarantee its contract. Moreover, they do
not use formal methods for specifying services, contracts, and compositions.
Without a formal basis it is not possible to justify through formal
verification the correctness conditions for service compositions and the
satisfaction of contractual obligations in service provisions. We remedy this
situation in this paper. We present a formal definition of services with
context-dependent contracts. We define a composition theory of services with
context-dependent contracts taking into consideration functional,
nonfunctional, legal and contextual information. Finally, we present a formal
verification approach that transforms the formal specification of service
composition into extended timed automata that can be verified using the model
checking tool UPPAAL.Comment: In Proceedings WWV 2011, arXiv:1108.208
Federated Embedded Systems – a review of the literature in related fields
This report is concerned with the vision of smart interconnected objects, a vision that has attracted much attention lately. In this paper, embedded, interconnected, open, and heterogeneous control systems are in focus, formally referred to as Federated Embedded Systems. To place FES into a context, a review of some related research directions is presented. This review includes such concepts as systems of systems, cyber-physical systems, ubiquitous
computing, internet of things, and multi-agent systems. Interestingly, the reviewed fields seem to overlap with each other in an increasing number of ways
Behavioral types in programming languages
A recent trend in programming language research is to use behav- ioral type theory to ensure various correctness properties of large- scale, communication-intensive systems. Behavioral types encompass concepts such as interfaces, communication protocols, contracts, and choreography. The successful application of behavioral types requires a solid understanding of several practical aspects, from their represen- tation in a concrete programming language, to their integration with other programming constructs such as methods and functions, to de- sign and monitoring methodologies that take behaviors into account. This survey provides an overview of the state of the art of these aspects, which we summarize as the pragmatics of behavioral types
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