Introducing an Upper bound on Capacity of Quantum Key Distillation

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Keykhosravi, Kamran | 2014

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 45902 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Aref, Mohammad Reza; Aminzadeh Gohari, Amin
Abstract:
In modern cryptography the main goal in symmetric cryptography algorithms is that the security of the protocol should be only dependent on the secrecy of key. Further, secret key agreement has a major role in perfect security. However, it is impossible to share a secrete key only by the use of a public channel and there must be another shared source. This source can be for instance random variables with some joint distribution (as in source model classical key distillation problem) or it can be some entangled quantum systems (as in quantum key distillation problem). The question here is that with the optimum efficiency, what is the maximum number of key bits that can be distilled from one copy of source. For this question no exact answer has been found yet but there are plenty of introduced upper and lower bounds. Here we introduce an upper bound which is a generalization of its classical case. Even though this bound is presented for the quantum problem, it may improve its classical version in some cases
Keywords:
Quantum Cryptography ; Quantum Information Theory ; Quantum Key Disstillation