Skype Traffic Identification

Skype uses strong encryption to secure communications inside the whole Skype network. Clients choose communication ports randomly. Therefore traditional port based or payload based identification of Skype traffic is not feasible. In this paper we introduce a novel flow dynamics based identification method to discover Skype host and voice calls as well. Our method uses only packet headers and the extracted flow level information. The whole identification process is scripted in Transact-SQL, thus it can be executed automatically. We also present the validation of the algorithm together with some analysis of the identification results.