Yahya S. Khiabani

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This paper considers the problem of end-to-end security enhancement by resorting to deliberate noise injected in ciphertexts. The main goal is to generate a degraded wiretap channel in the application layer over which Wyner-type secrecy encoding is invoked to deliver additional secure information. More specifically, we study secrecy enhancement of the Data(More)
This paper focuses on the problem of sharing secret keys using Automatic Repeat reQuest (ARQ) protocol. We consider cases where forward and feedback channels are erasure channels for a legitimate receiver (Bob) and an eavesdropper (Eve). In prior works, the wiretap channel is modeled as statistically independent packet erasure channels for Bob and Eve. In(More)
In this paper, we study the effect of channel errors on the performance of linear cryptanalysis against block ciphered system. We study DES block cipher working in cipher feedback mode (CFB) as a special case. In our model, eavesdropper launches linear attack by querying an oracle which provides her with corrupted ciphertexts over a binary symmetric channel(More)
The recently developed paradigm of cognitive radio wireless devices has been developed with the goal of achieving more customizable and efficient spectrum utilization of commonly used wireless frequency bands. The primary focus of such spectrum utilization approaches has been to discern occupancies and vacancies over portions of the wireless spectrum(More)
In this paper we propose an encoding-encryption approach to take advantage of intentional noise introduced in ciphertexts for a block cipher working in CFB or CBC mode. First of all, we provide a rigorous analysis of the impacts of channel degradation on block ciphered systems. We show that the overall channel can be modeled as a Finite State Markov Chain(More)
In this paper without tailoring to any physical channel condition or any restriction on adversary's computational resources we design a secrecy scheme with information leakage that decays at an exponential rate. The only advantage for legitimate users over eavesdropper is existence of a key source that is partially known by Eve. A key extractor based on a(More)
The main idea in this work is to design and analyze a symmetric key generation algorithm whereby we can strengthen wireless network security. Our main goal is generating a sequence of highly secure secret keys based on an ARQ based transmission mechanism that relies on the statistical independence of channel errors between the attacker and legitimate users.(More)
In this dissertation we try to achieve secrecy enhancement in communications by resorting to both cryptographic and information theoretic secrecy tools and metrics. Our objective is to unify tools and measures from cryptography community with techniques and metrics from information theory community that are utilized to provide privacy and confidentiality in(More)
In this paper without tailoring to any presumed condition on communication channel or any restriction on adversary's resources we design a secrecy scheme with information leakage that decays at an exponential rate. The only requirement for such an exponentially secure system is existence of a common key source between legitimate users that is partially(More)