Skype is one of the most popular voice-over-IP (VoIP) service providers. One of the main reasons for the popularity of Skype VoIP services is its unique set of features to protect privacy of VoIP calls such as strong encryption, proprietary protocols, unknown codecs, dynamic path selection, and the constant packet rate. In this paper, we propose a class of passive traffic analysis attacks to compromise privacy of Skype VoIP calls. The proposed attacks are based on application-level features extracted from VoIP call traces. The proposed attacks are evaluated by extensive experiments over different types of networks including commercialized anonymity networks and our campus network. The experiment results show that the proposed traffic analysis attacks can greatly compromise the privacy of Skype calls. Possible countermeasure to mitigate the proposed traffic analysis attacks are analyzed in this paper.
Zhu, Ye and Fu, Huirong, "Traffic Analysis Attacks on Skype VoIP Calls" (2011). Electrical Engineering & Computer Science Faculty Publications. 50.
Zhu, Y., , & Fu, H. (2011). Traffic analysis attacks on Skype VoIP calls. Computer Communications, 34(10), 1202-1212. doi:10.1016/j.comcom.2010.12.007
NOTICE: this is the author’s version of a work that was accepted for publication in Computer Communications. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Computer Communications, 34, 10, (07-01-2011); 10.1016/j.comcom.2010.12.007