Covert channels are a fundamental concept for cryptanalytic side-channel attacks. Covert timing channels use latency to carry data, and are the foundation for timing and cache-timing attacks. Covert storage channels instead utilize existing system bits to carry data, and are not historically used for cryptanalytic side-channel attacks. This paper introduces a new storage channel made available ...

We consider the problem of detecting covert channels within security-enforcing object-capability patterns. Traditional formalisms for reasoning about the security properties of object-capability patterns require one to be aware, a priori, of all possible mechanisms for covert information flow that might be present within a pattern, in order to detect covert channels within it. We show how the C...

This letter studies and compares the physical-layer security approach and the covert communication approach for a wiretap channel with a transmitter, an intended receiver and an eavesdropper. In order to make the comparison, we investigate the power allocation problems for maximizing the secrecy/covert rate subject to the transmit power constraint. Simulation results illustrate that if the eave...

BACKGROUND AND PURPOSE Unrecognized or unreported stroke-like symptoms, called covert symptoms, occur in persons free of clinical stroke. Whether covert symptoms are associated with subclinical brain infarcts (SBIs) is unknown. This study examined the association between covert stroke-like symptoms and SBI/stroke in persons with no history of stroke or transient ischemic attack. METHODS A tot...

Auditory perception and auditory imagery have been shown to activate overlapping brain regions. We hypothesized that these phenomena also share a common underlying neural representation. To assess this, we used electrocorticography intracranial recordings from epileptic patients performing an out loud or a silent reading task. In these tasks, short stories scrolled across a video screen in two ...

This paper uses jamming legitimate transmissions over a slotted ALOHA system as a means of covert communication. The resulting covert channel is found to be source dependent, and to have infinite memory. Hence, a characterization of the capacity of covert communication over such a medium is an inherently complex problem. Employing i.i.d. jamming strategies, this paper derives achievable rates f...

A Guide to Understanding Covert Channel Analysis of Trusted Systems provides a set of good practices related to covert channel analysis. We have written this guide to help the vendor and evaluator communities understand the requirements for covert channel analysis as described in the Department of Defense Trusted Computer System Evaluation Criteria (TCSEC). In an effort to provide guidance, we ...