Security proof of BB84 quantum key distribution (QKD) protocol and study of imperfections over the implementation of the weak+vacuum decoy-state QKD protocol

Papapanos, Christos; Παπαπάνος, Χρήστος

dc.contributor.author	Papapanos, Christos	en
dc.contributor.author	Παπαπάνος, Χρήστος	el
dc.date.accessioned	2020-11-22T08:37:29Z
dc.date.available	2020-11-22T08:37:29Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/51998
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.19696
dc.rights	Default License
dc.subject	Quantum protocols	en
dc.subject	Security proof	en
dc.subject	CSS codes	en
dc.subject	Quantum Key Distribution (QKD)	en
dc.subject	BB84 QKD	en
dc.subject	Decoy-state QKD	en
dc.subject	Weak+vacuum decoy-state QKD	en
dc.subject	Imperfections	en
dc.subject	Implementation	en
dc.subject	Afterpulse	el
dc.subject	Chromatic dispersion	en
dc.subject	Non ideal VOA	en
dc.subject	Κβαντικά πρωτόκολλα	el
dc.subject	Απόδειξη ασφαλείας	el
dc.subject	Κώδικες CSS	el
dc.subject	Ατέλειες	el
dc.subject	Υλοποίηση	el
dc.subject	Χρωματική διασπορά	el
dc.subject	Μη ιδανικός VOA	el
dc.title	Security proof of BB84 quantum key distribution (QKD) protocol and study of imperfections over the implementation of the weak+vacuum decoy-state QKD protocol	en
dc.contributor.department	Εργαστήριο Φωτονικών Επικοινωνιών	el
heal.type	bachelorThesis
heal.secondaryTitle	Απόδειξη Ασφαλείας του Πρωτοκόλλου Διανομής Κβαντικού Κλειδιού (QKD) BB84 και Μελέτη Ατελειών στην Υλοποίηση του Πρωτοκόλλου Weak+Vacuum Decoy-state QKD	el
heal.classification	Quantum protocols	en
heal.classification	Quantum optics	en
heal.language	el
heal.language	en
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2020-03-12
heal.abstract	Quantum cryptographic protocols exploit basic principles of physics in order to conceal the content of the transmitter's message from third parties. This seems to be the end of the interception of communications. However, just like the classical cryptographic protocols, comprehensive studies are needed in order to prove their security from any kind of possible attacks, namely to guarantee their security level information-theoretically. In the field of Quantum Key Distribution (QKD), where single photons are transferred through fiber networks, the non ideal features of optical components as well other implementation imperfections could cause significant security loopholes. Inspired from this research topic, this diploma thesis contributes to the study of practical real-time implementation of Discrete Variable-QKD (DV-QKD) protocols. This diploma thesis has three goals. The first goal is the brief study of the proof of security of BB84 QKD protocol using the concept of protocols' equivalence and the CSS codes; at the same time we manage to keep only the main steps of this proof so even readers lacking specialized knowledge will be able to understand it. The second goal of this diploma thesis is the study of the way that we can conduct the mathematical formulas for the efficiency metrics (Secure Key Rate, Quantum Bit Error Rate) of a group of protocols- the decoy-state protocols- in a system that uses a fiber optic for the transmittance. In order to accomplish our third goal we choose, from the aforementioned group of protocols, the weak+vacuum decoy-state QKD protocol. We study the way that the non ideal Variable Optical Attenuator (VOA) affects this protocol's efficiency by generalizing the vacuum decoy state and we conduct new formulas for studying the effect of the afterpulse phenomenon on the efficiency of this protocol. Then, we consider the effect of chromatic dispersion in a setup with two Mach-Zehnder interferometers which are used not only on the aforementioned protocols but on even more protocols, thus the mathematical formulas which we conduct are universal. We find the maximum possible generation rate of the Secure Key Rate that this setup can create as well as the value of each phase shifter of the two interferometers in relation to the communication's length and the error detection due to the interference Visibility that we want to succeed. Finally, we present a graphic representation of the previous imperfection on a Matlab environment.	en
heal.advisorName	Αβραμόπουλος, Ηρακλής	el
heal.committeeMemberName	Φικιώρης, Γεώργιος	el
heal.committeeMemberName	Ματσόπουλος, Γεώργιος	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών	el
heal.academicPublisherID	ntua
heal.numberOfPages	76 p.	en
heal.fullTextAvailability	false