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Les ordinateurs quantiques sont une technologie prometteuse qui pourrait permettre de faire des calculs qui sont impossibles pour les ordinateurs modernes dans un temps raison- nable. D’autre part, les techniques cryptographiques modernes se basent sur des problèmes computationnels difficiles pour assurer leur sécurité. Ainsi, l’arrivée des ordinateurs quan- tiques pourrait sévèrement compromettre la sécurité des techniques courantes. La distri- bution quantique de clés (QKD en anglais) est une façon de distribuer des clés de cryptage secrètes qui utilise des propriétés quantiques. Ceci fait en sorte qu’un malfaiteur (même avec un ordinateur quantique) ne pourrait pas essayer d’intercepter le message sans courir la chance d’induire des erreurs dans le message. En QKD, l’information (les qubits) est transmise via des fibres optiques ou l’air libre, mais la distance et la vitesse de transmission est limitée en ce moment. Le but de ce projet est de faire un circuit intégré qui servirait de détecteur pour un receveur QKD. Il utilisera des PDC (Photon-to-Digital Converter) et l’électronique rapide de 65 nm TSMC afin de livrer un receveur à haut débit. L’avan- tage d’un PDC est qu’il offre la possibilité d’adapter le détecteur pour l’application. Dans ce cas, du traitement de données et un circuit de fenêtrage ont été ajoutés pour rendre le receveur plus efficace. Le PDC contient aussi des TDC (time-to-digital converter) qui mesurent le temps d’arrivée des photons détectés. Parmi mes contributions originales, j’ai développé, implémenté et validé un circuit de fenêtrage pour les TDC ainsi qu’un circuit de catégorisation pour le QKD. Dans ce mémoire et dans l’article publié (chapitre 7), je présente ces contributions et je démontre ainsi que les PDC peuvent être des receveurs QKD qui offrent une excellente performance temporelle (22.7 ps gigue temporelle) qui est très attrayante pour le QKD. Le but du projet était de démontrer l’avantage des PDC et la tâche a été accomplie.

Quantum key distribution (QKD) is a method of secure key distribution which provides protection against the tampering and interception of information. Following the Bennet-Brassard 1984 (BB84) protocol of QKD, we select randomly from a set of bases in which to produce polarized photons and send the photons to a receiver, who measures them in a basis randomly selected from the same set. The fact that quantum mechanics prohibits the exact copying of a photon ensures that any eavesdropper who intercepts, measures, and attempts to pass the photons on to the receiver will be unable to faithfully reproduce that signal. The presence of the eavesdropper can then be detected, prior to any exchange of information, by an examination of the error rate between portions of the keys generated by the sender and receiver. Using a biphoton source, we have constructed a QKD system for use in research towards naval applications., Lieutenant, United States Navy, Approved for public release. Distribution is unlimited.

We report on a quantum key distribution field trial in the Copenhagen metropolitan area using true single photons from a quantum-dot-based near-deterministic source. A stable secret key generation rate of 2 kbit/s with 9.6-dB channel loss is achieved with a polarization-based BB84 scheme.

Quantum key distribution (QKD) protocols allow for information theoretically secure distribution of (classical) cryptographic key material. However, due to practical limitations the performance of QKD implementations is somewhat restricted. For this reason, it is crucial to find optimal protocol parameters, while guaranteeing information theoretic security. The performance of a QKD implementation is determined by the tightness of the underlying security analysis. In particular, the security analyses determines the key-rate, i.e., the amount of cryptographic key material that can be distributed per time unit. Nowadays, the security analyses of various QKD protocols are well understood. It is known that optimal protocol parameters, such as the number of decoy states and their intensities, can be found by solving a nonlinear optimization problem. The complexity of this optimization problem is typically handled by making a number of heuristic assumptions. For instance, the number of decoy states is restricted to only one or two, with one of the decoy intensities set to a fixed value, and vacuum states are ignored as they are assumed to contribute only marginally to the secure key-rate. These assumptions simplify the optimization problem and reduce the size of search space significantly. However, they also cause the security analysis to be non-tight, and thereby result in sub-optimal performance. In this work, we follow a more rigorous approach using both linear and nonlinear programs describing the optimization problem. Our approach, focusing on the decoy-state BB84 protocol, allows heuristic assumptions to be omitted, and therefore results in a tighter security analysis with better protocol parameters. We show an improved performance for the decoy-state BB84 QKD protocol, demonstrating that the heuristic assumptions typically made are too restrictive. Moreover, our improved optimization frameworks shows that the complexity of the performance optimization problem can al

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

This article presents basics of quantum key distribution BB84-like protocols. Brieflyexplains principles of their operations and impact of QBER on intrusion detection. Afterwards resultsof QKD simulations are presented as well as own QKD polygon draft (on multiplexed optical fibre).

Quantum key distribution (QKD) protocols allow for information theoretically secure distribution of (classical) cryptographic key material. However, due to practical limitations the performance of QKD implementations is somewhat restricted. For this reason, it is crucial to find optimal protocol parameters, while guaranteeing information theoretic security. The performance of a QKD implementation is determined by the tightness of the underlying security analysis. In particular, the security analyses determines the key-rate, i.e., the amount of cryptographic key material that can be distributed per time unit. Nowadays, the security analyses of various QKD protocols are well understood. It is known that optimal protocol parameters, such as the number of decoy states and their intensities, can be found by solving a nonlinear optimization problem. The complexity of this optimization problem is typically handled by making a number of heuristic assumptions. For instance, the number of decoy states is restricted to only one or two, with one of the decoy intensities set to a fixed value, and vacuum states are ignored as they are assumed to contribute only marginally to the secure key-rate. These assumptions simplify the optimization problem and reduce the size of search space significantly. However, they also cause the security analysis to be non-tight, and thereby result in sub-optimal performance. In this work, we follow a more rigorous approach using both linear and nonlinear programs describing the optimization problem. Our approach, focusing on the decoy-state BB84 protocol, allows heuristic assumptions to be omitted, and therefore results in a tighter security analysis with better protocol parameters. We show an improved performance for the decoy-state BB84 QKD protocol, demonstrating that the heuristic assumptions typically made are too restrictive. Moreover, our improved optimization frameworks shows that the complexity of the performance optimization problem can al

Quantum key distribution from satellites becomes particularly valuable when it can be used on a large network and on-demand to provide a symmetric encryption key to any two nodes. A constellation model is described which enables QKD-derived encryption keys to be established between any two ground stations with low latency. This is achieved through the use of low earth orbit trusted-node QKD satellites which create a buffer of keys with the ground stations they pass over, and geostationary relay satellites to transfer secure combinations of the keys to the ground stations. Regional and global network models are considered and the use of inter-satellite QKD links for balancing keys is assessed., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Space Systems Egineering

Quantum key distribution from satellites becomes particularly valuable when it can be used on a large network and on-demand to provide a symmetric encryption key to any two nodes. A constellation model is described which enables QKD-derived encryption keys to be established between any two ground stations with low latency. This is achieved through the use of low earth orbit trusted-node QKD satellites which create a buffer of keys with the ground stations they pass over, and geostationary relay satellites to transfer secure combinations of the keys to the ground stations. Regional and global network models are considered and the use of inter-satellite QKD links for balancing keys is assessed., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Space Systems Egineering

In dieser Doktorarbeit werden zwei Konzepte der Quanteninformationsverarbeitung realisiert. Der Quantenschlüsselaustausch ist revolutionär, weil er perfekte Sicherheit gewährleistet. Zahlreiche Quantenkryptografieprotokolle wurden schon untersucht. Zwei Probleme bestehen. Zum einen ist es sehr schwer, die Bedingungen herzustellen, die in den Annahmen für perfekte Sicherheit impliziert sind. Zum anderen sind die Reichweiten auf momentan etwa 200 km begrenzt, aufgrund des abnehmenden Signals gegenüber des konstanten Rauschens. Ein Experiment dieser Doktorarbeit beschäftigt sich mit dem ersten Problem. Insbesondere der übertragene Quantenzustands ist kritisch für die Sicherheit des Verfahrens. Es werden Einzelphotonen von Stickstoff- Fehlstellen-Zentren und zum ersten Mal von Silizium-Fehlstellen-Zentren für einen Quantenschlüsselaustausch mit Hilfe des BB84-Protokolls benutzt. Die Abweichung von idealen Einzelphotonenzuständen sowie deren Bedeutung für die Sicherheit werden analysiert. Die Übertragung von Quantenzuständen via Satellit könnte das Problem der begrenzten Reichweite lösen. Das neue Frequenz-Zeit- Protokoll eignet sich dafür besonders gut. Es wird während dieser Arbeit zum ersten Mal überhaupt implementiert. Umfangreiche Untersuchungen inklusive der Variation wesentlicher experimenteller Parameter geben Aufschluss über die Leistungsfähigkeit und Sicherheit des Protokolls. Außerdem werden elementare Bestandteile eines vollautomatischen Experiments zum Quantenschlüsselaustausch über Glasfasern in der sogenannten Time-bin-Implementierung mit autonomem Sender und Empfänger realisiert. Ein anderes Konzept der Quanteninformationsverarbeitung ist die Herstellung zufälliger Bitfolgen durch den Quantenzufall. Zufällige Bitfolgen haben zahlreiche Anwendungsgebiete in der Kryptografie und der Informatik. Die Realisierung eines Quantenzufallszahlengenerators mit mathematisch beschreibbarer und getesteter Zufälligkeit und hoher Bitrate wird ebenfalls beschrieben., In this thesis, photonic quantum states are used for experimental realisations of two different concepts of quantum information processing. Quantum key distribution (QKD) is revolutionary because it is the only cryptographic scheme offering unconditional security. Two major problems prevail: Firstly, matching the conditions for unconditional security is challenging, secondly, long distance communication beyond 200 km is very demanding because an increasingly attenuated quantum state starts to fail the competition with constant noise. One experiment accomplished in this thesis is concerned with the first problem. The realisation of the actual quantum state is critical. Single photon states from nitrogen and for the first time also silicon vacancy defect centres are used for a QKD transmission under the BB84 (Bennett and Brassard 1984). The deviation of the used single photon states from the ideal state is thoroughly investigated and the information an eavesdropper obtains due to this deviation is analysed. Transmitting quantum states via satellites is a potential solution to the limited achievable distances in QKD. A novel protocol particularly suited for this is implemented for the first time in this thesis, the frequency-time (FT) protocol. The protocol is thoroughly investigated by varying the experimental parameters over a wide range and by evaluating the impact on the performance and the security. Finally, big steps towards a fully automated fibre-based BB84 QKD experiment in the time-bin implementation with autonomous sender and receiver units are accomplished. Another important concept using quantum mechanical properties as a resource is a quantum random number generator (QRNG). Random numbers are used for various applications in computing and cryptography. A QRNG supplying bits with high and quantifiable randomness at a record-breaking rate is reported and the statistical properties of the random output is thoroughly tested.

In dieser Doktorarbeit werden zwei Konzepte der Quanteninformationsverarbeitung realisiert. Der Quantenschlüsselaustausch ist revolutionär, weil er perfekte Sicherheit gewährleistet. Zahlreiche Quantenkryptografieprotokolle wurden schon untersucht. Zwei Probleme bestehen. Zum einen ist es sehr schwer, die Bedingungen herzustellen, die in den Annahmen für perfekte Sicherheit impliziert sind. Zum anderen sind die Reichweiten auf momentan etwa 200 km begrenzt, aufgrund des abnehmenden Signals gegenüber des konstanten Rauschens. Ein Experiment dieser Doktorarbeit beschäftigt sich mit dem ersten Problem. Insbesondere der übertragene Quantenzustands ist kritisch für die Sicherheit des Verfahrens. Es werden Einzelphotonen von Stickstoff- Fehlstellen-Zentren und zum ersten Mal von Silizium-Fehlstellen-Zentren für einen Quantenschlüsselaustausch mit Hilfe des BB84-Protokolls benutzt. Die Abweichung von idealen Einzelphotonenzuständen sowie deren Bedeutung für die Sicherheit werden analysiert. Die Übertragung von Quantenzuständen via Satellit könnte das Problem der begrenzten Reichweite lösen. Das neue Frequenz-Zeit- Protokoll eignet sich dafür besonders gut. Es wird während dieser Arbeit zum ersten Mal überhaupt implementiert. Umfangreiche Untersuchungen inklusive der Variation wesentlicher experimenteller Parameter geben Aufschluss über die Leistungsfähigkeit und Sicherheit des Protokolls. Außerdem werden elementare Bestandteile eines vollautomatischen Experiments zum Quantenschlüsselaustausch über Glasfasern in der sogenannten Time-bin-Implementierung mit autonomem Sender und Empfänger realisiert. Ein anderes Konzept der Quanteninformationsverarbeitung ist die Herstellung zufälliger Bitfolgen durch den Quantenzufall. Zufällige Bitfolgen haben zahlreiche Anwendungsgebiete in der Kryptografie und der Informatik. Die Realisierung eines Quantenzufallszahlengenerators mit mathematisch beschreibbarer und getesteter Zufälligkeit und hoher Bitrate wird ebenfalls beschrieben., In this thesis, photonic quantum states are used for experimental realisations of two different concepts of quantum information processing. Quantum key distribution (QKD) is revolutionary because it is the only cryptographic scheme offering unconditional security. Two major problems prevail: Firstly, matching the conditions for unconditional security is challenging, secondly, long distance communication beyond 200 km is very demanding because an increasingly attenuated quantum state starts to fail the competition with constant noise. One experiment accomplished in this thesis is concerned with the first problem. The realisation of the actual quantum state is critical. Single photon states from nitrogen and for the first time also silicon vacancy defect centres are used for a QKD transmission under the BB84 (Bennett and Brassard 1984). The deviation of the used single photon states from the ideal state is thoroughly investigated and the information an eavesdropper obtains due to this deviation is analysed. Transmitting quantum states via satellites is a potential solution to the limited achievable distances in QKD. A novel protocol particularly suited for this is implemented for the first time in this thesis, the frequency-time (FT) protocol. The protocol is thoroughly investigated by varying the experimental parameters over a wide range and by evaluating the impact on the performance and the security. Finally, big steps towards a fully automated fibre-based BB84 QKD experiment in the time-bin implementation with autonomous sender and receiver units are accomplished. Another important concept using quantum mechanical properties as a resource is a quantum random number generator (QRNG). Random numbers are used for various applications in computing and cryptography. A QRNG supplying bits with high and quantifiable randomness at a record-breaking rate is reported and the statistical properties of the random output is thoroughly tested.

QKD simulator © is a web application aimed at simulating and analyzing Quantum Key Distribution protocols. The online simulator is powered by the QKD Simulation Toolkit, which has been designed and implemented to support customizing a wide range of parameters for individual components and sub-protocols, e.g., the quantum channel, sifting, error estimation, information reconciliation and privacy amplification. Each simulation run provides detailed information about the intermediate and final stages of the protocol.

QKD simulator © is a web application aimed at simulating and analyzing Quantum Key Distribution protocols. The online simulator is powered by the QKD Simulation Toolkit, which has been designed and implemented to support customizing a wide range of parameters for individual components and sub-protocols, e.g., the quantum channel, sifting, error estimation, information reconciliation and privacy amplification. Each simulation run provides detailed information about the intermediate and final stages of the protocol.

Quantum key distribution (QKD) protocols are intended to allow cryptographic keys to be generated and distributed in way that is provably secure based on inherent limitations, such as the no-cloning principle, imposed by quantum mechanics. This unique advantage compared with classical cryptography comes with an added difficulty: key bits in QKD protocols are encoded in analogue quantum states and their preparation is consequently subject to the usual imprecisions inevitable in any real world experiment. The negative impact of such imprecisions is illustrated for the BB84 QKD protocol. Following this, the main part of this thesis is concerned with the incorporation of such imprecisions in security proofs of the BB84 and two semi-device-independent protocols against the class of collective attacks. On a technical level, by contrast with the vast majority of security proofs developed since the turn of the century, in which recasting the protocol into an equivalent entanglement-based form features heavily in the analysis, the main results obtained here are approached directly from the prepare-and-measure perspective and in particular the connection with the no-cloning theorem and an early security proof by Fuchs et al. against the class of individual attacks is emphasised.This thesis also summarises, as an appendix, a separate project which introduces and defines a hierarchy of polytopes intermediate between the local and no-signalling polytopes from the field of Bell nonlocality., Doctorat en Sciences, info:eu-repo/semantics/nonPublished

[EN] The security is a research area in a continuous evolving field and represents one of the most important perspective future lines in telecommunications. This work is focused on new techniques and methods employing the properties of quantum physics with the aim of obtaining unconditional security. Currently, these techniques and methods lack a key rate close to the current transmission rate. In order to improve the quantum key transmission rate, this article proposes the use of cryptographic hash functions used in the privacy amplification layer to expand the bit rate relying on the properties of these functions., [ES] La seguridad es un campo de trabajo en continuo desarrollo y representa una de las líneas con mayor perspectiva de futuro dentro de las telecomunicaciones. Este trabajo se centra en las nuevas técnicas y procedimientos que emplean las propiedades de la física cuántica con el objetivo de obtener seguridad incondicional. Actualmente, estos sistemas de distribución de clave carecen de una tasa de clave equiparable con las tasas de transmisión actuales. Para lograr mejorar la tasa de transmisión de clave cuántica, se propone en este artículo el uso de las funciones hash criptográficas usadas en la capa de amplificación de privacidad para lograr ampliar la tasa binaria apoyándose en las propiedades de estas funciones. The security is a research area in a continuous evolving field and represents one of the most important perspective future lines in telecommunications. This work is focused on new techniques and methods employing the properties of quantum physics with the aim of obtaining unconditional security. Currently, these techniques and methods lack a key rate close to the current transmission rate. In order to improve the quantum key transmission rate, this article proposes the use of cryptographic hash functions used in the privacy amplification layer to expand the bit rate relying on the properties of these functions.

[EN] The security is a research area in a continuous evolving field and represents one of the most important perspective future lines in telecommunications. This work is focused on new techniques and methods employing the properties of quantum physics with the aim of obtaining unconditional security. Currently, these techniques and methods lack a key rate close to the current transmission rate. In order to improve the quantum key transmission rate, this article proposes the use of cryptographic hash functions used in the privacy amplification layer to expand the bit rate relying on the properties of these functions., [ES] La seguridad es un campo de trabajo en continuo desarrollo y representa una de las líneas con mayor perspectiva de futuro dentro de las telecomunicaciones. Este trabajo se centra en las nuevas técnicas y procedimientos que emplean las propiedades de la física cuántica con el objetivo de obtener seguridad incondicional. Actualmente, estos sistemas de distribución de clave carecen de una tasa de clave equiparable con las tasas de transmisión actuales. Para lograr mejorar la tasa de transmisión de clave cuántica, se propone en este artículo el uso de las funciones hash criptográficas usadas en la capa de amplificación de privacidad para lograr ampliar la tasa binaria apoyándose en las propiedades de estas funciones. The security is a research area in a continuous evolving field and represents one of the most important perspective future lines in telecommunications. This work is focused on new techniques and methods employing the properties of quantum physics with the aim of obtaining unconditional security. Currently, these techniques and methods lack a key rate close to the current transmission rate. In order to improve the quantum key transmission rate, this article proposes the use of cryptographic hash functions used in the privacy amplification layer to expand the bit rate relying on the properties of these functions.

Estudio, desarrollo y caracterización de diferentes sistemas fotónicos para realizar un transmisor pasivo de distribución de claves cuánticas (QKD) utilizando luz coherente., [ANGLÈS] This thesis makes use of novel ideas to demonstrate proof of concept experiments, which could then further develop into practical passive QKD sources. Different tasks related to the source have been carried out. Particularly, our efforts have been focused on assembling and characterizing, step by step, the required optical processes for the source. One of the objectives was to achieve phase incoherence between consecutive optical pulses generated by the laser diode. This fact ensures no information leakage by tracking back the phases of the optical pulses. Another objective was to study second order non-linear optical processes with phase randomized coherent optical pulses. This is the first time that such particular optical pulses are characterized on second order harmonic and sum-frequency generation., [CASTELLÀ] En esta tesis se hace uso de ideas novedosas para demostrar la prueba de experimentos conceptuales, que luego podrían desarrollar en la práctica fuentes pasivas de QKD. En particular, nuestros esfuerzos se han centrado en el montaje y caracterización, paso a paso, de los procesos ópticos requeridos para la fuente. Uno de los objetivos es lograr la incoherencia de fase entre pulsos ópticos consecutivos generados por el diodo laser. Otro de los objetivos es estudiar los procesos ópticos no lineales de segundo orden con fase aleatoria generados utilizando pulsos ópticos coherentes. Esta es la primera vez que tales pulsos ópticos se caracterizan mediante la generación del segundo armónico y la generación de la suma de frecuencias., [CATALÀ] En aquesta tesi es fa ús d'idees noves per demostrar la prova d'experiments conceptuals, que després podrien desenvolupar a la pràctica fonts passives de QKD. En particular, els nostres esforços s'han centrat en el muntatge i caracterització, pas a pas, dels processos òptics requerits per la font. Un dels objectius és aconseguir la incoherència de fase entre polsos òptics consecutius generats pel diode laser. Un altre dels objectius és estudiar els processos òptics no lineals de segon ordre amb fase aleatòria generats utilitzant polsos òptics coherents. Aquesta és la primera vegada que aquests polsos òptics es caracteritzen mitjançant la generació del segon harmònic i la generació de la suma de freqüències.

Bakalárska práca sa venuje kvantovej kryptografií. V teoretickej čast je rozbor problematiky bezpečnej distribúcie kľúčov v infraštruktúre optických vláknových sietí. Analyzované sú metódy ako kvantová distribúcia kľúčov (QKD) alebo distribúcia kľúčov na základe parametrov optického kanálu, včetne opisu bezpečnostných a technických obmedzení metód. Okrem distribúcie kľúčov sa práca snaží aj o priblíženie základných princípov optickej infraštruktúry využívanej pri QKD a v neposlednom rade aj postkvantovej kryptografii (včetne porovnania s kvantovou kryptografiou a aktuálnych protokolov). V rámci praktickej časti bol preukázaný vplyv makroohybu vlákna a odrazivosti u konektorov na chod kvantového systému. Ďalej bolo preukázané, že teplota a svetlo pôsobiace na optickú infraštruktúru QKD nemajú zásadný vplyv., The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.

Bakalárska práca sa venuje kvantovej kryptografií. V teoretickej čast je rozbor problematiky bezpečnej distribúcie kľúčov v infraštruktúre optických vláknových sietí. Analyzované sú metódy ako kvantová distribúcia kľúčov (QKD) alebo distribúcia kľúčov na základe parametrov optického kanálu, včetne opisu bezpečnostných a technických obmedzení metód. Okrem distribúcie kľúčov sa práca snaží aj o priblíženie základných princípov optickej infraštruktúry využívanej pri QKD a v neposlednom rade aj postkvantovej kryptografii (včetne porovnania s kvantovou kryptografiou a aktuálnych protokolov). V rámci praktickej časti bol preukázaný vplyv makroohybu vlákna a odrazivosti u konektorov na chod kvantového systému. Ďalej bolo preukázané, že teplota a svetlo pôsobiace na optickú infraštruktúru QKD nemajú zásadný vplyv., The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.

Bakalárska práca sa venuje kvantovej kryptografií. V teoretickej čast je rozbor problematiky bezpečnej distribúcie kľúčov v infraštruktúre optických vláknových sietí. Analyzované sú metódy ako kvantová distribúcia kľúčov (QKD) alebo distribúcia kľúčov na základe parametrov optického kanálu, včetne opisu bezpečnostných a technických obmedzení metód. Okrem distribúcie kľúčov sa práca snaží aj o priblíženie základných princípov optickej infraštruktúry využívanej pri QKD a v neposlednom rade aj postkvantovej kryptografii (včetne porovnania s kvantovou kryptografiou a aktuálnych protokolov). V rámci praktickej časti bol preukázaný vplyv makroohybu vlákna a odrazivosti u konektorov na chod kvantového systému. Ďalej bolo preukázané, že teplota a svetlo pôsobiace na optickú infraštruktúru QKD nemajú zásadný vplyv., The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.

Bakalárska práca sa venuje kvantovej kryptografií. V teoretickej čast je rozbor problematiky bezpečnej distribúcie kľúčov v infraštruktúre optických vláknových sietí. Analyzované sú metódy ako kvantová distribúcia kľúčov (QKD) alebo distribúcia kľúčov na základe parametrov optického kanálu, včetne opisu bezpečnostných a technických obmedzení metód. Okrem distribúcie kľúčov sa práca snaží aj o priblíženie základných princípov optickej infraštruktúry využívanej pri QKD a v neposlednom rade aj postkvantovej kryptografii (včetne porovnania s kvantovou kryptografiou a aktuálnych protokolov). V rámci praktickej časti bol preukázaný vplyv makroohybu vlákna a odrazivosti u konektorov na chod kvantového systému. Ďalej bolo preukázané, že teplota a svetlo pôsobiace na optickú infraštruktúru QKD nemajú zásadný vplyv., The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.

Bakalárska práca sa venuje kvantovej kryptografií. V teoretickej čast je rozbor problematiky bezpečnej distribúcie kľúčov v infraštruktúre optických vláknových sietí. Analyzované sú metódy ako kvantová distribúcia kľúčov (QKD) alebo distribúcia kľúčov na základe parametrov optického kanálu, včetne opisu bezpečnostných a technických obmedzení metód. Okrem distribúcie kľúčov sa práca snaží aj o priblíženie základných princípov optickej infraštruktúry využívanej pri QKD a v neposlednom rade aj postkvantovej kryptografii (včetne porovnania s kvantovou kryptografiou a aktuálnych protokolov). V rámci praktickej časti bol preukázaný vplyv makroohybu vlákna a odrazivosti u konektorov na chod kvantového systému. Ďalej bolo preukázané, že teplota a svetlo pôsobiace na optickú infraštruktúru QKD nemajú zásadný vplyv., The bachelor thesis focuses on quantum cryptography. In the theoretical part, there is an analysis of secure key distribution in the fiber-optic infrastructure. Methods such as quantum key distribution (QKD) or physical layer secret key generation for fiber-optic networks are analyzed, including a description of the security and technical limitations of the methods. The thesis also attempts to interpret some basic principles of the optic infrastructure used in QKD. In addition to the distribution of keys, the thesis also tries to approximate the basic principles of the optic infrastructure used in QKD and, last but not least, post-quantum cryptography (including a comparison with quantum cryptography and current protocols). In the practical part, the effect of the macrobending of the fiber and the reflectivity of the connectors on the operation of the quantum system was demonstrated. It was also demonstrated that temperature and light acting on the QKD optic infrastructure do not have a fundamental effect.