  We present here the first work to propose different mechanisms for hiding
data in the Extensible Messaging and Presence Protocol (XMPP). This is a very
popular instant messaging protocol used by many messaging platforms such as
Google Talk, Cisco, LiveJournal and many others. Our paper describes how to
send a secret message from one XMPP client to another, without raising the
suspicion of any intermediaries. The methods described primarily focus on using
the underlying protocol as a means for steganography, unlike other related
works that try to hide data in the content of instant messages. In doing so, we
provide a more robust means of data hiding and additionally offer some
preliminary analysis of its general security, in particular against
entropic-based steganalysis.
