This paper presents experimental results of the implementation of network
steganography method called RSTEG (Retransmission Steganography). The main idea
of RSTEG is to not acknowledge a successfully received packet to intentionally
invoke retransmission. The retransmitted packet carries a steganogram instead
of user data in the payload field. RSTEG can be applied to many network
protocols that utilize retransmissions. We present experimental results for
RSTEG applied to TCP (Transmission Control Protocol) as TCP is the most popular
network protocol which ensures reliable data transfer.