Investigative support for information confidentiality

Abstract

With the ubiquity and pervasiveness of computers in daily activities and with the ever-growing complexity of communication networks and protocols, covert channels are becoming an eminent threat to the confidentiality of information. In light of this threat, we propose a technique to detect confidential information leakage via protocol-based covert channels. Although several works examine covert channel detection and analysis from the perspective of information theory by, for instance, analysing channel capacities, we propose a different technique that tackles the problem from a different perspective. The proposed technique takes an algebraic approach using relations. It provides tests to verify the existence of a leakage of information via a monitored covert channel. It also provides computations which show how the information was leaked if a leakage exists. We also discuss possible applications of the proposed technique in cryptanalysis and digital forensics based on a known-plaintext attack. We report on a prototype tool that allows for the automation of the proposed technique.