Covert Communication Using Port Knocking

Data theft and espionage attacks, which is evolved rapidly, impose the need to develop new and stealthy communication techniques to protect sensitive data that is transferred over the Internet. These new techniques should be built in different way than traditional and known communication techniques, in order to eschew detection and monitoring tools. This paper proposes a new covert channel for stealthy communication. The communication channel uses Least Significant Bit steganography and Tariq port knocking to hide data, besides that GnuPG encryption is applied before hiding the data to add another layer of protection. The communication efficiency has been evaluated using Peak Signal to Noise Ratio, and the result indicates better image quality compared with other techniques. Also, the maximum capacity and transfer rate of the channel have been evaluated, the channel is capable to achieve 152 bps as a maximum transmission rate in its current implementation.