390 research outputs found

    Intrusion Tolerance: Concepts and Design Principles. A Tutorial

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    In traditional dependability, fault tolerance has been the workhorse of the many solutions published over the years. Classical security-related work has on the other hand privileged, with few exceptions, intrusion prevention, or intrusion detection without systematic forms of processing the intrusion symptoms. A new approach has slowly emerged during the past decade, and gained impressive momentum recently: intrusion tolerance. The purpose of this tutorial is to explain the underlying concepts and design principles. The tutorial reviews previous results under the light of intrusion tolerance (IT), introduces the fundamental ideas behind IT, and presents recent advances of the state-of-the-art, coming from European and US research efforts devoted to IT. The program of the tutorial will address: a review of the dependability and security background; introduction of the fundamental concepts of intrusion tolerance (IT); intrusion-aware fault models; intrusion prevention; intrusion detection; IT strategies and mechanisms; design methodologies for IT systems; examples of IT systems and protocol

    Enhancing efficiency of Byzantine-tolerant coordination protocols via hash functions

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    Abstract. Distributed protocols resilient to Byzantine failures are notorious to be costly from the computational and communication point of view. In this paper we discuss the role that collision–resistant hash functions can have in enhancing the efficiency of Byzantine–tolerant coordination protocols. In particular, we show two settings in which their use leads to a remarkable improvement of the system performance in case of large data or large populations. More precisely, we show how they can be applied to the implementation of atomic shared objects, and propose a technique that combines randomization and hash functions. We discuss also the earnings of these approaches and compute their complexity.

    Monkeys, typewriters and networks: the internet in the light of the theory of accidental excellence

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    Viewed in the light of the theory of accidental excellence, there is much to suggest that the success of the Internet and its various protocols derives from a communications technology accident, or better, a series of accidents. In the early 1990s, many experts still saw the Internet as an academic toy that would soon vanish into thin air again. The Internet probably gained its reputation as an academic toy largely because it violated the basic principles of traditional communications networks. The quarrel about paradigms that erupted in the 1970s between the telephony world and the newly emerging Internet community was not, however, only about transmission technology doctrines. It was also about the question – still unresolved today – as to who actually governs the flow of information: the operators or the users of the network? The paper first describes various network architectures in relation to the communication cultures expressed in their make-up. It then examines the creative environment found at the nodes of the network, whose coincidental importance for the Internet boom must not be forgotten. Finally, the example of Usenet is taken to look at the kind of regulatory practices that have emerged in the communications services provided within the framework of a decentralised network architecture. --

    Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 1: Army fault tolerant architecture overview

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    Digital computing systems needed for Army programs such as the Computer-Aided Low Altitude Helicopter Flight Program and the Armored Systems Modernization (ASM) vehicles may be characterized by high computational throughput and input/output bandwidth, hard real-time response, high reliability and availability, and maintainability, testability, and producibility requirements. In addition, such a system should be affordable to produce, procure, maintain, and upgrade. To address these needs, the Army Fault Tolerant Architecture (AFTA) is being designed and constructed under a three-year program comprised of a conceptual study, detailed design and fabrication, and demonstration and validation phases. Described here are the results of the conceptual study phase of the AFTA development. Given here is an introduction to the AFTA program, its objectives, and key elements of its technical approach. A format is designed for representing mission requirements in a manner suitable for first order AFTA sizing and analysis, followed by a discussion of the current state of mission requirements acquisition for the targeted Army missions. An overview is given of AFTA's architectural theory of operation
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