18,042 research outputs found
Detection and Filtering of Collaborative Malicious Users in Reputation System using Quality Repository Approach
Online reputation system is gaining popularity as it helps a user to be sure
about the quality of a product/service he wants to buy. Nonetheless online
reputation system is not immune from attack. Dealing with malicious ratings in
reputation systems has been recognized as an important but difficult task. This
problem is challenging when the number of true user's ratings is relatively
small and unfair ratings plays majority in rated values. In this paper, we have
proposed a new method to find malicious users in online reputation systems
using Quality Repository Approach (QRA). We mainly concentrated on anomaly
detection in both rating values and the malicious users. QRA is very efficient
to detect malicious user ratings and aggregate true ratings. The proposed
reputation system has been evaluated through simulations and it is concluded
that the QRA based system significantly reduces the impact of unfair ratings
and improve trust on reputation score with lower false positive as compared to
other method used for the purpose.Comment: 14 pages, 5 figures, 5 tables, submitted to ICACCI 2013, Mysore,
indi
Conceptualizing human resilience in the face of the global epidemiology of cyber attacks
Computer security is a complex global phenomenon where different populations interact, and the infection of one person creates risk for another. Given the dynamics and scope of cyber campaigns, studies of local resilience without reference to global populations are inadequate. In this paper we describe a set of minimal requirements for implementing a global epidemiological infrastructure to understand and respond to large-scale computer security outbreaks. We enumerate the relevant dimensions, the applicable measurement tools, and define a systematic approach to evaluate cyber security resilience. From the experience in conceptualizing and designing a cross-national coordinated phishing resilience evaluation we describe the cultural, logistic, and regulatory challenges to this proposed public health approach to global computer assault resilience. We conclude that mechanisms for systematic evaluations of global attacks and the resilience against those attacks exist. Coordinated global science is needed to address organised global ecrime
Chiron: A Robust Recommendation System with Graph Regularizer
Recommendation systems have been widely used by commercial service providers
for giving suggestions to users. Collaborative filtering (CF) systems, one of
the most popular recommendation systems, utilize the history of behaviors of
the aggregate user-base to provide individual recommendations and are effective
when almost all users faithfully express their opinions. However, they are
vulnerable to malicious users biasing their inputs in order to change the
overall ratings of a specific group of items. CF systems largely fall into two
categories - neighborhood-based and (matrix) factorization-based - and the
presence of adversarial input can influence recommendations in both categories,
leading to instabilities in estimation and prediction. Although the robustness
of different collaborative filtering algorithms has been extensively studied,
designing an efficient system that is immune to manipulation remains a
significant challenge. In this work we propose a novel "hybrid" recommendation
system with an adaptive graph-based user/item similarity-regularization -
"Chiron". Chiron ties the performance benefits of dimensionality reduction
(through factorization) with the advantage of neighborhood clustering (through
regularization). We demonstrate, using extensive comparative experiments, that
Chiron is resistant to manipulation by large and lethal attacks
A Formal Framework for Modeling Trust and Reputation in Collective Adaptive Systems
Trust and reputation models for distributed, collaborative systems have been
studied and applied in several domains, in order to stimulate cooperation while
preventing selfish and malicious behaviors. Nonetheless, such models have
received less attention in the process of specifying and analyzing formally the
functionalities of the systems mentioned above. The objective of this paper is
to define a process algebraic framework for the modeling of systems that use
(i) trust and reputation to govern the interactions among nodes, and (ii)
communication models characterized by a high level of adaptiveness and
flexibility. Hence, we propose a formalism for verifying, through model
checking techniques, the robustness of these systems with respect to the
typical attacks conducted against webs of trust.Comment: In Proceedings FORECAST 2016, arXiv:1607.0200
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