BEGIN:VCALENDAR VERSION:2.0 PRODID:-//linuxsoftware.nz//NONSGML Joyous v1.4//EN BEGIN:VEVENT SUMMARY:Asymmetric Quantum Cryptography and Multipartite Correlations DTSTART:20220316T150000Z DTEND:20220316T170000Z DTSTAMP:20260626T122140Z UID:6da86d0c-8fc1-4806-908a-d6bb273e6ac2 SEQUENCE:2 CREATED:20220314T114504Z DESCRIPTION: AbstractThe subject of this thesis is the analysis of secure asymmetric cryptographic schemes\, and the study of the main resource for information processing protocols\, the total\, classical and quantum multi partite correlations.Motivated by the usefulness of secure multiparty comp utation as a privacy-protecting data analysis tool\, we proposed a practic al quantum realization of randomized oblivious transfer. Our solution is a imed at targeting the limitations of security and efficiency faced by the classical schemes for oblivious transfer. A detailed security proof was wr itten for the protocol. We also provide preliminary results of performance from an experimental setup based on an entangled photons source and polar ization encoding.The impossibility results for achieving unconditionally s ecure bit commitment have driven the research for secure solutions under s everal different assumptions. We propose a criteria for ranking the comple xity of such assumptions\, together with new functionality\, called the as ymmetric quantum beamer\, which is minimal under the listed criteria. Usin g this new assumption we develop a universally composable bit commitment p rotocol with linear com­ plexity in its security parameter.Based on previ ous work for a correlation hierarchy for probability distributions\, we fo r­ malize a framework of correlation structures for quantum systems. We e xplore some of its mathematical properties\, computational complexity\, us e for information compression of quantum states\, and some aspects of cate gorization of correlations by the way they are dis­ tributed as well as b y their nature (classical/quantum). Additionally\, we present a practical application for the correlation structures framework for early classificat ion of time series data sets. The proposed method is based on selectively cutting correlations that are not directly connected to the class variable until a criterion of optimality is satisfied. The algorithm was able to s uccessfully guess the class of test data from real world sources using onl y a few initial time steps. Its versatility for application for other prob lems is highlighted.Finally\, we lay the foundations of a quantum algorith mic complexity theory based on the dc-QTM model. We conclude that\, althou gh the algorithmic complexity of a physical state and its classical descri ption are equivalent\, they can be differentiated while taking the role of a resource to compute another state. Additionally\, we prove that the cha in rule does not hold for this version of algorithmic complexity and argue how that result can be used to define the complexity of correlations in q uantum systems. LAST-MODIFIED:20220315T153250Z LOCATION:Online URL:http://df.vps.tecnico.ulisboa.pt/pt/eventos/asymmetric-quantum-cryptog raphy-and-multipartite-correlations/ X-ALT-DESC;FMTTYPE=text/html:

Abstract

The subject of this thesis is the analysis of s ecure asymmetric cryptographic schemes\, and the study of the main resourc e for information processing protocols\, the total\, classical and quantum multipartite correlations.

Motivated by the usefulness of secure multiparty computation as a privacy-protecting data a nalysis tool\, we proposed a practical quantum realization of randomized o blivious transfer. Our solution is aimed at targeting the limitations of s ecurity and efficiency faced by the classical schemes for oblivious transf er. A detailed security proof was written for the protocol. We also provid e preliminary results of performance from an experimental setup based on a n entangled photons source and polarization encoding.

The impossibility results for achieving unconditionally secure bi t commitment have driven the research for secure solutions under several d ifferent assumptions. We propose a criteria for ranking the complexity of such assumptions\, together with new functionality\, called the asymmet ric quantum beamer\, which is minimal under the listed c riteria. Using this new assumption we develop a universally composable bit commitment protocol with linear com­ plexity in its security parameter.< /p>

Based on previous work for a correlation hier archy for probability distributions\, we for­ malize a framework of corre lation structures for quantum systems. We explore some of its mathematical properties\, computational complexity\, use for information compression o f quantum states\, and some aspects of categorization of correlations by t he way they are dis­ tributed as well as by their nature (classical/quant um). Additionally\, we present a practical application for the correlation structures framework for early classification of time series data sets. T he proposed method is based on selectively cutting correlations that are n ot directly connected to the class variable until a criterion of optimalit y is satisfied. The algorithm was able to successfully guess the class of test data from real world sources using only a few initial time steps. Its versatility for application for other problems is highlighted.

Finally\, we lay the foundations of a quantum algorithm ic complexity theory based on the dc-QTM model. We conclude that\, althoug h the algorithmic complexity of a physical state and its classical descrip tion are equivalent\, they can be differentiated while taking the role of a resource to compute another state. Additionally\, we prove that the chai n rule does not hold for this version of algorithmic complexity and argue how that result can be used to define the complexity of correlations in qu antum systems.

END:VEVENT END:VCALENDAR