3 research outputs found

    Collaborative Caching for efficient and Robust Certificate Authority Services in Mobile Ad-Hoc Networks

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    Security in Mobile Ad-Hoc Network (MANET) is getting a lot of attention due to its inherent vulnerability to a wide spectrum of attacks. Threats exist in every layer of MANET stack, and different solutions have been adapted for each security problem. Additionally, availability is an important criterion in most MANET solutions, but many security frameworks did not consider it. Public-Key Infrastructure (PKI) is no exception, and its deployment in MANET needs major design and implementation modifications that can fit constraints unique to this environment. Our focus in this dissertation is to adapt and increase the availability of Certificate Authority (CA) services, as a major PKI entity, in MANET. Several attempts have been proposed to deal with the problem of deploying CA in MANET to provide a generic public-key framework, but each either ends up sacrificing system security or availability. Here, the main goal of our work is to provide a solution that addresses performance and security issues of providing MANET-based PKI. Particularly, we would like to maintain the availability of the services provided by CA while keeping the network\u27s packet overhead as low as possible. In this dissertation, we present a MANET-based framework suitable for exchanging public-key certificates by collaborative caching between MANET clients. We show that our system can meet the challenges of providing robust and secure CA services in MANET. Augmented by simulation results, we demonstrate quantitatively the feasibility of our work as we were able to reduce network overhead associated with threshold based CA queries up to 92% as compared to related work in addition to having a very short response time. The dependency on CA servers has been reduced, and the system was able to tolerate as much as two-third inoperative CA servers without noticeable decrease in the service performance

    Quorumcast routing by multispace search

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    In this paper, we present a multispace search algorithm, MUSQ, for the quorumcast routing problem. We first prune the candidate set to reduce the original search space. Some of the unqualified links for the optimal tree are removed from the network. Then a multispace search algorithm is used to solve the quorumcast routing problem. By altering the original objective function, the original problem instance is transformed into a series of gradually more simplified problem instances with smoother terrain surfaces. A local search algorithm is used to solve each problem instance, from the simplest structure to the original structure, and the solutions of the more simplified problem instances are used to guide the search of more complicated ones. Experimental results showed that this new method improved the performance of the existing heuristic algorithms

    Quorumcast Routing by Multispace Search

    No full text
    In this paper, we present a multispace search algorithm, MUSQ, for the quorumcast routing problem. We first prune the candidate set to reduce the original search space. Some of the unqualified links for the optimal tree are removed from the network. Then a multispace search algorithm is used to solve the quorumcast routing problem. By altering the original objective function, the original problem instance is transformed into a series of gradually more simplified problem instances with smoother terrain surfaces. A local search algorithm is used to solve each problem instance, from the simplest structure to the original structure, and the solutions of the more simplified problem instances are used to guide the search of more complicated ones. Experimental results showed that this new method improved the performance of the existing heuristic algorithms. 1 Introduction Many networking applications require multicast connections in addition to conventional unicast connections. Multicastin..
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