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Quantum cryptography : Public key distribution and coin tossing

01 Jan 1984-pp 175-179
About: The article was published on 1984-01-01 and is currently open access. It has received 5589 citations till now. The article focuses on the topics: Quantum cryptography & Quantum money.
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Journal ArticleDOI
TL;DR: In this paper, four measures of distinguishability for quantum-mechanical states are surveyed from the point of view of the cryptographer with a particular eye on applications in quantum cryptography.
Abstract: This paper, mostly expository in nature, surveys four measures of distinguishability for quantum-mechanical states. This is done from the point of view of the cryptographer with a particular eye on applications in quantum cryptography. Each of the measures considered is rooted in an analogous classical measure of distinguishability for probability distributions: namely, the probability of an identification error, the Kolmogorov distance, the Bhattacharyya coefficient, and the Shannon (1948) distinguishability (as defined through mutual information). These measures have a long history of use in statistical pattern recognition and classical cryptography. We obtain several inequalities that relate the quantum distinguishability measures to each other, one of which may be crucial for proving the security of quantum cryptographic key distribution. In another vein, these measures and their connecting inequalities are used to define a single notion of cryptographic exponential indistinguishability for two families of quantum states. This is a tool that may prove useful in the analysis of various quantum-cryptographic protocols.

759 citations

Journal ArticleDOI
TL;DR: In this article, the authors reported the violation of the CHSH inequality measured by two observers separated by 144 km between the Canary Islands of La Palma and Tenerife via an optical free-space link using the Optical Ground Station (OGS) of the European Space Agency (ESA).
Abstract: Quantum Entanglement is the essence of quantum physics and inspires fundamental questions about the principles of nature. Moreover it is also the basis for emerging technologies of quantum information processing such as quantum cryptography, quantum teleportation and quantum computation. Bell's discovery, that correlations measured on entangled quantum systems are at variance with a local realistic picture led to a flurry of experiments confirming the quantum predictions. However, it is still experimentally undecided whether quantum entanglement can survive global distances, as predicted by quantum theory. Here we report the violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality measured by two observers separated by 144 km between the Canary Islands of La Palma and Tenerife via an optical free-space link using the Optical Ground Station (OGS) of the European Space Agency (ESA). Furthermore we used the entangled pairs to generate a quantum cryptographic key under experimental conditions and constraints characteristic for a Space-to-ground experiment. The distance in our experiment exceeds all previous free-space experiments by more than one order of magnitude and exploits the limit for ground-based free-space communication; significantly longer distances can only be reached using air- or space-based platforms. The range achieved thereby demonstrates the feasibility of quantum communication in space, involving satellites or the International Space Station (ISS).

748 citations

Proceedings ArticleDOI
27 Jun 2004
TL;DR: This paper proves the security of the Bennett-Brassard (BB84) quantum key distribution protocol in the case where the source and detector are under the limited control of an adversary.
Abstract: This paper prove the security of the Bennett-Brassard (BB84) quantum key distribution protocol in the case where the source and detector are under the limited control of an adversary. This proof applies when both the source and the detector have small basis-dependent flaws, as is typical in practical implementations of the protocol. The estimation of the key generation rate in some special cases: sources that emit weak coherent states, detectors with basis-dependent efficiency, and misaligned sources and detectors.

682 citations

Journal Article
TL;DR: In this paper, a short review of ideas in quantum information theory is presented at the level of advanced undergraduate knowledge, together with some useful tools for quantum mechanics of open systems and a new resource: quantum information.
Abstract: In this thesis I present a short review of ideas in quantum information theory. The first chapter contains introductory material, sketching the central ideas of probability and information theory. Quantum mechanics is presented at the level of advanced undergraduate knowledge, together with some useful tools for quantum mechanics of open systems. In the second chapter I outline how classical information is represented in quantum systems and what this means for agents trying to extract information from these systems. The final chapter presents a new resource: quantum information. This resource has some bewildering applications which have been discovered in the last ten years, and continually presents us with unexpected insights into quantum theory and the universe. The treatment is pedagogical and suitable for beginning graduates in the field.

635 citations

Journal ArticleDOI
TL;DR: At the heart of such optimism has been the widespread belief that unconditionally secure quantum bit commitment (QBC) schemes exist, which is put into very serious doubt by showing.
Abstract: We show that all proposed quantum bit commitment schemes are insecure because the sender, Alice, can almost always cheat successfully by using an Einstein-Podolsky-Rosen--type of attack and delaying her measurement until she opens her commitment.

625 citations