13 documents found, page 1 of 2
Coordenação desacoplada tolerante a faltas bizantinas
Bessani, Alysson NevesTese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Engenharia Elétrica; Sistemas distribuídos abertos são tipicamente compostos por um número desconhecido e variável de processos executando em um ambiente heterogêneo, onde as comunicações muitas vezes requerem desconexões temporárias e segurança contra ações maliciosas. A coordenação por espaço de tuplas ...
O padrão UMIOP como base para comunicação de grupo confiável em sistemas distri...
Bessani, Alysson NevesDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica.; O conceito de grupo de objetos é uma abstração largamente usada no tratamento de replicação em sistemas distribuídos tolerantes a faltas. Os sistemas que se baseiam neste conceito geralmente utilizam algum tipo de suporte de comunicação de grupo (SCG), que oferece comunicação m...
Architecture, Services and Protocols for CRUTIAL
Abou El Kalan, Anas; Baina, Amine; Beitollahi, Hakem; Bessani, Alysson Neves; Bondavalli, Andrea; Correia, Miguel; Daidone, Alessandro; Dantas, WagnerThis document describes the complete specification of the architecture, services and protocols of the project CRUTIAL. The CRUTIAL Architecture intends to reply to a grand challenge of computer science and control engineering: how to achieve resilience of critical information infrastructures (CII), in particular in the electrical sector. In general lines, the document starts by presenting the main architectural...
Minimal Byzantine Fault Tolerance: Algorithm and Evaluation
Veronese, Giuliana Santos; Correia, Miguel; Bessani, Alysson Neves; Lung, Lau Cheuk; Verissimo, PauloThis paper presents two asynchronous Byzantine faulttolerant state machine replication (BFT) algorithms that are minimal in several senses. First, they require only 2 f +1 replicas, instead of the usual 3 f +1. Second, the trusted service in which this reduction of replicas is based is arguably minimal, so it is simple to verify and implement (which is possible even using commercial trusted hardware). Third, in...
Experimental Validation of Architectural Solutions
Franceschinis, Giuliana; Alata, Eric; Antunes, João; Beitollah, Hakem; Bessani, Alysson Neves; Correia, Miguel; Dantas, Wagner; Deconinck, GeertIn this deliverable the experimental results carried out in four different contexts are reported. The first contribution concerns an experimental campaign performed using the AJECT (Attack inJECTion) tool able to emulate different types of attackers behaviour and to collect information on the effect of such attacks on the target system performance. This tool is also used to perform some of the experiments described...
Minimal Byzantine Fault Tolerance
Veronese, Giuliana Santos; Correia, Miguel; Lung, Lau Cheuk; Bessani, Alysson NevesThis paper presents two Byzantine fault-tolerant state machine replication (BFT) algorithms that are minimal in several senses. First, they require only 2 f +1 replicas, instead of the usual 3 f +1. Second, the trusted service in which this reduction of replicas is based is arguably minimal: it provides an interface with a single function and is composed only by a counter and a signature generation primitive. T...
On the Effects of Diversity on Intrusion Tolerance
Bessani, Alysson Neves; Obelheiro, Rafael R.; Sousa, Paulo; Gashi, IlirThe security gains of intrusion-tolerant systems are directly dependent on the assumption that system components fail independently of one another. The coverage of this assumption in a real-world deployment depends on how diversity is employed, using, for example, diverse off-the-shelf components. In this paper we detail a study we have done with vulnerability data, reported in the period 1999 to 2007, which we...
Resilient Intrusion Tolerance through Proactive and Reactive Recovery
Sousa, Paulo; Bessani, Alysson Neves; Correia, Miguel; Neves, Nuno Ferreira; Veríssimo, PauloPrevious works have studied how to use proactive recovery to build intrusion-tolerant replicated systems that are resilient to any number of faults, as long as recoveries are faster than an upper-bound on fault production assumed at system deployment time. In this work, we propose a complementary approach that combines proactive recovery with services that allow correct replicas to react and recover replicas th...
Decoupled Quorum-based Byzantine-Resilient Coordination in Open Distributed Sys...
Bessani, Alysson Neves; Correia, Miguel; Fraga, Joni da Silva; Lung, Lau CheukOpen distributed systems are typically composed by an unknown number of processes running in heterogeneous hosts. Their communication often requires tolerance to temporary disconnections and security against malicious actions. Tuple spaces are a well-known coordination model for this kind of systems. They can support communication that is decoupled both in time and space. There are currently several implementat...
Intrusion-Tolerant Protection for Critical Infrastructures
Bessani, Alysson Neves; Sousa, Paulo; Correia, Miguel; Neves, Nuno Ferreira; Veríssimo, PauloToday's critical infrastructures like the Power Grid are essentially physical processes controlled by computers connected by networks. They are usually as vulnerable as any other interconnected computer system, but their failure has a high socio-economic impact. The paper describes a new construct for the protection of these infrastructures, based on distributed algorithms and mechanisms implemented between a s...