Browsing by Author "Mohamed, Emad Eldin"

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    Leaker identification in multicast communication
    (Springer Nature Switzerland AG, 2012) Mohamed, Emad Eldin; Guerchi, Driss
    Multicast is a communication mode in which data is exchanged among multiple end systems. An important concern in multicast communications is the protection of copyrights. While preventing copyright violations seems very difficult, tracing copyright violators (leaker identification) is more feasible and can be used as a deterrence alternative. In order to identify leakers in a multicast environment, every receiver should obtain a uniquely marked copy of the data. However, delivering unique copies from the sender to the receivers is inefficient. This paper investigates multicast leaker identification and introduces an efficient solution that is based on binary search tree. We introduce the notion of suspicious set that includes suspected end systems. When a leak is detected, all receivers are inserted in the suspicious set. Using a binary search, the suspicious set is refined successively until it includes only the leakers. An analytical study is conducted to evaluate the proposed solution. © Springer-Verlag Berlin Heidelberg 2012.
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    LPC-based narrowband speech steganography
    (Springer Nature Switzerland AG, 2012) Guerchi, Driss; Mohamed, Emad Eldin
    This paper proposes a new speech steganography system for secure sound massages sharing. This system exploits the advancements in speech processing to hide efficiently secret speech in narrowband cover speech. Linear predictive coding is used to represent the secret speech with reduced number of parameters. These parameters are embedded in selective perceptually-irrelevant frequency locations of the cover speech. Objective and subjective measures show that the resulting stego speech, which contains the secret message, is indistinguishable from the cover speech. © Springer-Verlag Berlin Heidelberg 2012.
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    OMAC : a new access control architecture for overlay multicast communications
    (John Wiley & Sons, Inc., 2011) Mohamed, Emad Eldin; Barka, Ezedin
    Multicast communications concern the transfer of data among multiple users. Multicast communications can be provided at the network layera-an example is IP multicasta-or at the application layer, also called overlay multicast. An important issue in multicast communications is to control how different usersa-senders, receivers, and delivery nodesa-access the transmitted data as well as the network resources. Many researchers have proposed solutions addressing access control in IP multicast. However, little attention has been paid to overlay multicast. In this paper, we investigate the access control issues in overlay multicast and present OMAC: a new solution to address these issues. OMAC provides access control for senders, receivers, and delivery nodes in overlay multicast. The proposed architecture, which is based on symmetric key cryptosystem, centralizes the authentication process in one server whereas it distributes the authorization process among the delivery nodes. Moreover, delivery nodes are utilized as a buffer zone between end systems and the authentication server, making it less exposed to malicious end systems. To evaluate our work, we have used simulation to compare the performance of OMAC against previous solutions. Results of the simulation show that OMAC outperforms previous multicast access control schemes. © 2010 John Wiley & Sons, Ltd.
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    PSCAN : a port scanning network covert channel
    (IEEE Computer Society, 2016) Mohamed, Emad Eldin; Mnaouer, Adel Ben; Barka, Ezedin
    This paper introduces PSCAN, a port scanning-based network covert channel that violates non-discretionary system security policy that does not allow data transfer from a given process (the sender) to another given process (the receiver). Using PSCAN, the sender opens and closes network ports in a way that encodes covert data. The receiver performs a synchronized port scanning procedure on the sender's host to determine which ports are open and which ones are closed then decodes the data. The paper defines the covert channel and analyzes its data rate, stealthiness, and robustness. In addition, the paper investigates countermeasures against the channel. © 2016 IEEE.