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Capacity and Security of Cooperative Information Systems with Correlated Sources

Salehkalaibar, Sadaf | 2014

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 45865 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Aref, Mohammad Reza
  7. Abstract:
  8. The main problem in network information theory is how to send some sources in a network with multiple transmitters and receivers, in the presence of the noise and the interference.This problem is not solved in its general form and it needs source coding and channel coding. With the increase of users in a network, the secrecy becomes a challenging issue. The information-theoretic security is independent of the computational complexity.In this thesis, we investigate the transmission of correlated sources over information theoretic networks and study secrecy constraints in these networks. First, we study the secrecy of a one-receiver, two-eavesdropper broadcast channel with three degraded message sets. We consider three types of secrecy constraints: in the first type, we define perfect secrecy constraints at both eavesdroppers. In the second type, we define perfect secrecy constraint at one eavesdropper and imperfect secrecy constraint at the other. In the third type, we define imperfect secrecy constraints at both eavesdroppers. We find inner and outer bounds to the secrecy capacity region of this model and determine the secrecy capacity region for some special cases. Next, we study the active attack from an information theoretic approach. In this attack, the adversary can read the messages of the transmitter and can change it and send it to the receiver. We investigate the effect of fixed-length coding and variable-length coding on the problem modeling. We propose two structures for this attack: distortion-based and probability of error-based. We define three problems based on these structures and state our main results. We also consider transmission of correlated sources over a relay channel. We find sufficient conditions using separate source-channel coding and also joint scheme. We use partial decode-and-forward strategy at the relay. We compare these schemes through an example. Finally, we study the transmission of correlated sources over multiple-access wiretap channels. We obtain sufficient conditions using separate source-channel coding, hybrid coding and uncoded transmission. We consider the Gaussian case and find the optimal source-channel rate in some special cases
  9. Keywords:
  10. Channel Coding ; Source Coding ; Information Theoretic Security ; Active Attack ; one-Receiver, Two-Eavesdropper Broadcast Channel ; Multiple Access Wiretap Channel

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