  Steganography is an ancient art that encompasses various techniques of
information hiding, the aim of which is to secret information into a carrier
message. Steganographic methods are usually aimed at hiding the very existence
of the communication. Due to the rise in popularity of IP telephony, together
with the large volume of data and variety of protocols involved, it is
currently attracting the attention of the research community as a perfect
carrier for steganographic purposes. This paper is a survey of the existing
VoIP steganography (steganophony) methods and their countermeasures.
