International Journal of Information Security

, Volume 9, Issue 5, pp 313–325 | Cite as

Analysis of information leakage from encrypted Skype conversations

  • Benoît DupasquierEmail author
  • Stefan Burschka
  • Kieran McLaughlin
  • Sakir Sezer
Regular Contribution


Voice over IP (VoIP) has experienced a tremendous growth over the last few years and is now widely used among the population and for business purposes. The security of such VoIP systems is often assumed, creating a false sense of privacy. This paper investigates in detail the leakage of information from Skype, a widely used and protected VoIP application. Experiments have shown that isolated phonemes can be classified and given sentences identified. By using the dynamic time warping (DTW) algorithm, frequently used in speech processing, an accuracy of 60% can be reached. The results can be further improved by choosing specific training data and reach an accuracy of 83% under specific conditions. The initial results being speaker dependent, an approach involving the Kalman filter is proposed to extract the kernel of all training signals.


Information security Privacy Skype Voice over IP (VoIP) 


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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Benoît Dupasquier
    • 1
    Email author
  • Stefan Burschka
    • 1
  • Kieran McLaughlin
    • 1
  • Sakir Sezer
    • 1
  1. 1.Centre for Secure Information Technologies (CSIT)Queen’s University of BelfastBelfastNorthern Ireland, UK

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