A Secure and Robust Covert Channel Based on Secret Sharing Scheme.

Network covert channel (referred to as network steganography) is a covert communication technique that uses the redundancies of network protocols to transfer secret information. While encryption only protects communication from being decoded by unauthorised parties, a covert channel aims to hide the very existence of the secret communication. More recently focus has shifted towards network protocols based covert channels because the huge amount of data and vast number of different protocols in the Internet seems ideal as a high-bandwidth vehicle for covert communication. However, few approaches which can embed secret information with both great security and robustness ensured have been worked out by so far. In this paper, we propose a novel packet length based covert channel exploiting the secret sharing scheme in order to overcome the drawbacks of existing schemes. A comprehensive set of corresponding experiment results and security analysis show that the proposed covert channel is provably secure and with great robustness than that of the existing algorithms.