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...

Covert communication refers to the process of communicating data through a channel that is neither designed, nor intended to transfer information. Traditionally, covert channels are considered as security threats in computer systems and a great deal of attention has been given to countermeasures for covert communication schemes. The evolution of computer networks led the communication community...

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...

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Covert channels evade isolation mechanisms between multiple parties in the cloud. Especially cache covert channels allow the transmission of several hundred kilobits per second between unprivileged user programs in separate virtual machines. However, caches are small and shared and thus cache-based communication is susceptible to noise from any system activity and interrupts. The feasibility of...

For extremely sensitive applications, it may be advantageous for users to transmit certain types of data covertly over the network. This provides an additional layer of security to that provided by the different layers of the protocol stack. In this paper we present a covert side channel that uses the 802.11 MAC rate switching protocol. The covert channel provides a general method to hide commu...

Information hiding in JPEG2000 compressed images is investigated in this research. The challenges of covert communication in this state-of-the-art image codec are analyzed and a steganographic scheme is then proposed to reliably embed high-volume data into the JPEG2000 bitstream. A special mode of JPEG2000 is employed, and its usage and functions are explained and justified. Experimental result...

This article examines women's covert use of contraceptives, that is, their use of a method without their husbands' knowledge. Three questions are addressed: (1) How is covert use measured? (2) How prevalent is it? and (3) What are the factors underlying covert use? Existing studies are used together with survey and qualitative data collected in 1997 in an urban setting in Zambia from married wo...

Covert channels are a security threat for information systems, since they permit illegal flows, and sometimes leaks, of classified data. Although numerous descriptions have been given at a concrete level, relatively little work has been carried out at a more abstract level, outside probabilistic models. In this paper, we propose a definition of covert channels based on encoding and decoding bin...