We define a probabilistic model for the NRL Pump and using FHP-murφ show experimentally that there exists a probabilistic covert channel whose capacity depends on various NRL Pump parameters (e.g. buffer size, number of samples in the moving average, etc).

The paper concerns available steganographic techniques that can be used for creating covert channels for VoIP (Voice over Internet Protocol) streams. Apart from characterizing existing steganographic methods we provide new insights by presenting two new techniques. The first one is network steganography solution which exploits free/unused protocols’ fields and is known for IP, UDP or TCP protoc...

The creation of covert channels in public computer networks can prove an effective means of information hiding and secret communication. With the widespread adoption of the Internet the TCP/IP suite of protocols have become pervasive, and therefore an attractive target for covert channel exploitation. This paper gives a brief overview of covert channels in communication networks, and presents a...

the aim of this study was to examine the effect of overt and covert motivationalself-talk on perceived exertion and performance in a progressive exercise untilexhaustion in wrestlers. the population consisted of wrestlers in urmia and 15volunteer subjects were selected. this study was performed in three sessions with aone-week interval. the first session was held without self–talk while the sec...

A covert channel is a mechanism that can be used to communicate data across network or between processes within the system by violating the networks/ systems security policy and in a manner that goes unnoticed. An effective covert channel is the one that is undetectable by the adversary and can provide high degree of privacy. The goal of the covert channel is to communicate data from one host t...

We address the problem of detecting the presence of hidden messages in audio. The detector is based on the characteristics of the denoised residuals of the audio file, which may consist of a mixture of speech and music data. A set of generalized moments of the audio signal is measured in terms of objective and perceptual quality measures. The detector discriminates between cover and stego files...

This paper addresses a method to solve a node discovery problem in a complex network. Covert nodes which exist in a social network do not appear in the records which are observed on the communication or collaborative activities among the nodes. Discovering the covert nodes refers to identifying suspicious records in which the covert nodes would appear, or suspicious nodes which would be the nei...

Network covert channels enable a policy-breaking network communication (e.g., within botnets). Within the last years, new covert channel techniques arose which are based on the capability of protocol switching. Such protocol switching covert channels operate within overlay networks and can (as a special case) contain their own internal control protocols. We present the first approach to effecti...

Communication is not necessarily made secure by the use of encryption alone. The mere existence of communication is often enough to raise suspicion and trigger investigative actions. Covert channels aim to hide the very existence of the communication. The huge amount of data and vast number of different protocols in the Internet makes it ideal as a high-bandwidth vehicle for covert communicatio...

The Transportation Security Administration (TSA) uses undercover, or covert, testing to approximate techniques that terrorists may use to identify vulnerabilities in and measure the performance of airport security systems. During these tests, undercover inspectors attempt to pass threat objects through passenger and baggage screening systems, and access secure airport areas. In response to a co...