What are covert channel algorithms?

Question

Covert channels are normally used for communicating illegally or for some hidden communications, but I am trying to figure out what covert channel algorithms might be.

Has anyone heard of this term before and what does it mean?

How covert channel algorithms could be implemented in non-Computing environments?

Answer 1

Covert channel algorithms is most commonly used as a name given to a set of algorithms used in IDS/IPS (Intrusion Detection/Prevention Systems) to detect, analyze and identify covert channels in TCP/IP networks, for example by probabilistic statistical analysis by e.g. using the Markov model TCP packet analysis, Bayesian inference and other algorithms, deterministic by static traffic analysis, rule set matching, or by several other techniques / algorithms that might be in place with various intrusion detection systems.

Suggested further reading:

• Network Covert Channels: Design, Analysis, Detection, and Elimination (Serdar Cabuk, Purdue University - PDF)
• Covert channels analysis in TCP/IP networks (Pierre Allix, IFIPS School of Engineering University of Paris­-Sud XI, Orsay, France - PDF)
• A Covert Channel Detection Algorithm Based on TCP Markov Model (Jiangtao Zhai ; Sch. of Autom., Nanjing Univ. of Sci. & Technol., Nanjing, China ; Guangjie Liu ; Yuewei Dai)
• A Robust Network Covert Channel Algorithm Based on Spread Coding (NIU Xiaopeng*, LI Qingbao, WANG Zuo)
• An Approach to Analyze Covert Channel Based on Finite State Machine (Xiong Liu ; Dept. of Comput. Sci. & Technol., Tsinghua Univ., Beijing, China ; Jian-guo Hao ; Yi-qi Dai)