In the previous years, Skype has gained more and more popularity, since it is seen as the best VoIP software with good quality of sound, ease of use and one that works everywhere and with every OS. Because of its great diffusion, both the operators and the users are, for different reasons, interested in detecting Skype traffic.In this paper we propose a real-time algorithm (named Skype-Hunter) to detect and classify Skype traffic. In more detail, this novel method, by means of both signature-based and statistical procedures, is able to correctly reveal and classify the signaling traffic as well as the data traffic (calls and file transfers). To assess the effectiveness of the algorithm, experimental tests have been performed with several traffic data sets, collected in different network scenarios. Our system outperforms the 'classical' statistical traffic classifiers as well as the state-of-the-art ad hoc Skype classifier.
The increasing number of network attacks causes growing problems for network operators and users. Thus, detecting anomalous traffic is of primary interest in IP networks management. In this paper we address the problem considering a method based on PCA for detecting network anomalies. In more detail, we present a new technique that extends the state of the art in PCA based anomaly detection. Indeed, by means of the Kullback-Leibler divergence we are able to obtain great improvements with respect to the performance of the "classical" approach. Moreover we also introduce a method for identifying the flows responsible for an anomaly detected at the aggregated level. The performance analysis, presented in this paper, demonstrates the effectiveness of the proposed method
The increasing number of network attacks causes growing problems for network operators and users. Thus, detecting anomalous traffic is of primary interest in IP networks management. In this paper, we address the problem considering a method based on PCA for detecting network anomalies. In more detail, this paper presents a new technique that extends the state of the art in PCA-based anomaly detection. Indeed, by means of multi-scale analysis and Kullback-Leibler divergence, we are able to obtain great improvements with respect to the performance of the 'classical' approach. Moreover, we also introduce a method for identifying the flows responsible for an anomaly detected at the aggregated level. The performance analysis, presented in this paper, demonstrates the effectiveness of the proposed metho
The recent introduction of the smart grids poses the need for a distributed communication infrastructure able to efficiently transmit the energy measurements collected by the smart meters, while simultaneously coping with several privacy and security constraints. In this work we introduce a novel communication architecture able to efficiently solve such a problem. Our proposal is based on a heterogeneous architecture that makes use of functional nodes (namely the privacy peers) that are interposed between the users and the utility server. The proposed architecture is able to deal with both the need of anonymizing the measurement data (by implementing a Secure Multiparty Computation method) and of simultaneously attributing these data to the users for billing purposes. Moreover, we also show that our architecture is robust to both semi-honest and malicious adversaries
In this Chapter we give an overview of statistical methods for anomaly detection (AD), thereby targeting an audience of practitioners with general knowledge of statistics. We focus on the applicability of the methods by stating and comparing the conditions in which they can be applied and by discussing the parameters that need to be set
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