Decision makers in the field of national security, counterterrorism and counterinsurgency are faced with an uncertain, adaptive and asymmetrical threat. It should come as no surprise that a great need exists to understand covert organizations, the structure of which becomes known partially only after an attack or operation has occurred. What is known however is that many covert networks are org...

Covert channels are used for the secret transfer of information. Unlike encryption, which only protects the information from unauthorised observers, covert channels aim to hide the very existence of the communication. The huge amount of data and vast number of different network protocols in the Internet makes it an ideal high-capacity vehicle for covert communication. Covert channels pose a ser...

Covert communication aims to hide the very existence of wireless transmissions in order to guarantee a strong security in wireless networks. In this work, we examine the possibility and achievable performance of covert communication in one-way relay networks. Specifically, the relay is greedy and opportunistically transmits its own information to the destination covertly on top of forwarding th...

Covert channels can be used to circumvent system and network policies by establishing communications that have not been considered in the design of the computing system. We construct a covert channel between different computing systems that utilizes audio modulation/demodulation to exchange data between the computing systems over the air medium. The underlying network stack is based on a commun...

Interindividual variations in DNA repair capacity/efficiency linked to the presence of polymorphisms in DNA repair-related genes have been suggested to account for different risk of developing cancers. In this review article, on the basis of breast cancer formation as a model, we propose a 'hide-then-hit' hypothesis indicating the importance of escaping checkpoint surveillance for sub-optimal D...

Covert channels may be dangerous to company networks as they can lead to the leakage of confidential information. However, it is hard to assess what bandwidth of a covert channel poses a serious threat. Generally, it depends on the security policy that is implemented by the organisation concerned. The ideal case will be to eliminate all possibilities of hidden communication, but practically it ...

Lost audio packet steganography (LACK) is a steganography technique established on the VoIP network. LACK provides a high-capacity covert channel over VoIP network by artificially delaying and dropping a number of packets in use to convey stegnogram. However, the increasing loss of packets will hurt the quality of the VoIP service. The quality deterioration will not only affect the legitimate V...

We present a protocol for sending data over a common class of low-bandwidth covert channels. Covert channels exist in most communications systems and allow individuals to communicate truly undetectably. However, covert channels are seldom used due to their complexity. Our protocol is both practical and secure against attack by powerful adversaries. We implement our protocol on a standard platfo...

A general framework for exploiting covert channels in combinatorial games is presented. The framework is applicable to all combinatorial games, including Chess and Go, but is applied to the game of Tic-Tac-Toe for ease of experimental analysis. The security and capacity of the resulting covert channel are analyzed experimentally. By considering the ways in which a passive adversary can attempt ...

Under certain environmental conditions, naturally transforming bacteria are induced to pick up DNA released into the environment by other cells of the same or closely related species and, by homologous recombination, integrate that DNA into their chromosome. The selective pressures responsible for the evolution and maintenance of this form of genetic outcrossing, or sex, in bacteria are not kno...