  This paper introduces SkyDe (Skype Hide), a new steganographic method that
utilizes Skype encrypted packets with silence to provide the means for
clandestine communication. It is possible to reuse packets that do not carry
voice signals for steganographic purposes because Skype does not use any
silence suppression mechanism. The method's proof-of-concept implementation and
first experimental results are presented. They prove that the method is
feasible and offers steganographic bandwidth as high as 2.8 kbps.
