In this paper, we examine general mechanisms that a covert channel may exploit and derive new minimum requirements for setting up a covert channel. We also propose a new classification of covert channels based on our analysis. Unlike the non-interference approaches, our approach is constructive, allowing the direct examination of system architectures at different abstraction levels for the pres...

This paper presents an overview of different concepts regarding covert channels. It discusses the various classifications and the detailing of various fields used to manipulate for the covert channel execution. Different evaluation criteria’s are presented for measuring the strength of covert channels. The defenses and prevention schemes for this covert channel will also be discussed. This pape...

Computer network is unpredictable due to information warfare and is prone to various attacks. Such attacks on network compromise the most important attribute, the privacy. Most of such attacks are devised using special communication channel called ``Covert Channel''. The word ``Covert'' stands for hidden or non-transparent. Network Covert Channel is a concealed communication path within legitim...

In this paper, we propose CoCo, a novel framework for establishing covert timing channels. The CoCo covert channel modulates the covert message in the inter-packet delays of the network flows, while a coding algorithm is used to ensure the robustness of the covert message to different perturbations. The CoCo covert channel is adjustable: by adjusting certain parameters one can trade off differe...

Covert channels is a vital setup in the analysing the strength of security in a network. Covert Channel is illegitimate channelling over the secured channel and establishes a malicious conversation. The trap-door set in such channels proliferates making covert channel sophisticated to detect their presence in network firewall. This is due to the intricate covert scheme that enables to build rob...

In this paper we analyze the possibility for malicious agents to transmit an information possibly hidden in a Multi Level Security System via a covert channel. We give a framework for which we get two decidability results. Firstly, given a code and a system one can decide whether the system allows a covert channel for this code. Secondly, one can decide whether there exists a code to transmit o...

Covert channels emerged in mystery and departed in