Despite extensive research, covert channels are a principal threat to information security. Covert channels employ specially-crafted content or timing characteristics to transmit internal information to external attackers. Most techniques for detecting covert channels model legitimate network traffic. However, such an approach may not be applicable in dynamic virtualized environments because tr...

Although both anonymity and covert channels are part of the larger topic of information hiding, there also exists an intrinsic linkage between anonymity and covert channels. This linkage was illustrated in [1]; however, [1] just scratched the surface of the interplay between covert channels and anonymity, without a formal analysis of the related issues. This paper begins the process of formaliz...

Network covert channels enable a policy-breaking network communication (e.g., within botnets). Within the last years, new covert channel techniques occurred which are based on the capability of protocol switching. There are currently no means available to counter these new techniques. In this paper we present the first approach to effectively limit the bandwidth of such covert channels by intro...

A network covert channel violates security rules and leaks information imperceptibly. Many researchers have been studying how to construct it, and the basic methods involve exploiting packets head, packets sorting and packets timing, etc. To construct a more secret covert channel, this paper proposes a novel approach based on packet classification. With this method, covert information is encode...

While the secure transaction schedulers in multilevel secure database systems synchronize transactions cleared at different security levels, they must consider the problem of covert channel. Through the covert channel, malicious users leak secret information in a way of intentional interference among the transactions that they invoked. Much work had been done for closing the covert channel. Alt...

Cloud computing is becoming increasingly popular because of the dynamic deployment of computing service. Another advantage of cloud is that data confidentiality is protected by the cloud provider with the virtualization technology. However, a covert channel can break the isolation of the virtualization platform and leak confidential information without letting it known by virtual machines. In t...

Attention can be directed to particular spatial locations, or to objects that appear at anticipated points in time. While most work has focused on spatial or temporal attention in isolation, we investigated covert tracking of smoothly moving objects, which requires continuous coordination of both. We tested two propositions about the neural and cognitive basis of this operation: first that cove...

Covert Channel are the methods to conceal a message in the volatile medium carrier such as radio signal and network packets. Until now, covert channels based on the packet length produce abnormal packet length when the length of the message is long. Abnormal packet length, especially in the normal network will expose the covert channels to network security perimeter. Therefore, it motivates the...