On Characterizing and Measuring Out-of-Band Covert Channels

摘要: A methodology for characterizing and measuring out-of-band covert channels (OOB-CCs) is proposed used to evaluate covert-acoustic (i.e., established using speakers microphones). OOB-CCs are low-probability of detection/low-probability interception commodity devices that not traditionally communication (e.g., speaker microphone, display FM radio, etc.). To date, have been declared "covert" if the signals establish these could be perceived by a human adversary. This work examines from perspective passive adversary argues different required in order effectively assess OOB-CCs. Traditional systems measured their capacity bit error rate; while important parameters, they do capture key measures OOB-CCs: namely, probability an detecting channel amount data two covertly communicating parties can exchange without being detected. As result, adoption measure steganographic (in bits) transferred through OOB-CC before adversary's reaches given threshold. The theoretical discrete memoryless as well additive white Gaussian noise calculated this paper case study performed OOB channels, when uses energy detector detect communication. reveals conditions under which achieve perfect steganography communicated risk detection).