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Application of cryptography in information systems
Mika, Pavel ; Ivánek, Jiří (advisor) ; Dvořák, Jan (referee)
(in English): This thesis describes and compares the most popular algorithms used in information systems. Specifically, there are: Vernam cipher, DES, 3DES, AES, and Blowfish (symmetric cryptography) and Diffie-Hellman key exchange, RSA, ElGamal, McEliece and systems based on elliptic curves (asymmetric cryptography). The thesis deals with the areas of information security, in particular the various security mechanisms (confidentiality, availability, integrity, authentication, authorization and non-repudiation), which are secured by using cryptography. There is also mentioned the theme of standardization, where the responsible institutions and some standards are presented. Described algorithms are compared using several criteria (time, throughput, memory needed for implementation, avalanche effect and key lengths) in the final chapter. Data used for comparison are taken from other studies and scientific materials.
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Static methods for detection DDoS attacks
Miško, Lukáš ; Dvořák, Jan (referee) ; Blažek, Petr (advisor)
This thesis contains a theoretical basic for solution to issue of network anomalies with use of static methods and it also contains software as a solution for detection of network attacks. The main point of thesis is detection of DoS (Denial of Service) attacks. In thesis is located an analysis of DoS attacks rate categorization. Further in thesis is located analysis of protocols TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), their possible use to attacks SYN flood and UDP flood. Here are analysed three static methods and their detailed description. There is also a analysis of collected data and their comparison in the thesis. Thesis contains description and the results testing of software which is used to detect attacks in network, at the end.
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Traffic detection and analysis using SSL/TLS
Hutar, Jan ; Dvořák, Jan (referee) ; Smékal, David (advisor)
This diploma thesis deals with a detection and analysis of secure connections of electro- nic communication through SSL/TLS protocols. The thesis begins with introduction to SSL/TLS protocols. Thereafter, an analysis of messages used to establish secure con- nections using STARTTLS and postal protocols SMTP, POP3, and IMAP was made. Metadata detection and extraction of secured simplex and duplex connections take place using deep packet inspection tools. The tool of choice is the nDPI library from the Ntop project. The library was extended to detect the connections and extract the metadata based on studies and analysis of transmitted messages. Finally, testing is performed on a training data set and a basic analysis of acquired metadata is made.
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Fully-differential fractional frequency filters
Zapletal, Miroslav ; Dvořák, Jan (referee) ; Langhammer, Lukáš (advisor)
This diploma thesis is concentrated to fully differential and non-differential fractional-order filters with active elements. It describes how we can obtain fractional-order fully-differential filters design from non-differential design, thesis describes realization in OrCad program and simulation of this project. The first part of the thesis concerns theoretical analysis of frequency filters, active elements and fractional-order filters. The second part of the thesis includes designs of filters and simulations of differential structures and rest of non-differential structures simulation. The following part of the thesis concerns practical realization and experimental measurment of differential fractional-order filter. In the last part of this project, thesis evaluates all results which were revealed in our simulations and experimental measurment.
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The principles of private law
Čermák, Dalibor ; Dvořák, Jan (advisor) ; Elischer, David (referee)
The Principles of Private Law In my thesis I occupied myself mainly with representative principles that master private law and that should lead to the implementation of the idea of justice as an ultimate goal of a legal set of rules in general. Despite of Sisyphean character of this task and impossibility of reaching it, there is nothing that can discourage from trying it again and again. I would like to admit that this attempt was at least ambitious and meaningful. Inability of perfect recognition "an sich" turns attention into extralegal sources of information, such as ethics, political sciences, sociology, economy and the head of all sciences - philosophy. This thesis also reflects intuitive approach to the principles of private law as a result of dependency on my personal preferences and cited sources and their authors (which also reflects my own disposition). The main issue was a function of the principles of private law in the normative set of rules. These principles make an important place in the normative set of rules as they form its limits. We can hardly imagine its "commission" without such principles of private law. They protect the integrity and the compactness, because Czech private law is nowadays extremely heterogeneous complex of rules. According to the restriction mentioned in the...
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The impact of altered realtions upon the duration of an obligation
Raffaiová, Markéta ; Dvořák, Jan (advisor) ; Elischer, David (referee)
1. Summary The Influence of a Change of Circumstances on the Existence of an Obligation The purpose of my thesis is to present a brief outline of the problems concerning the impact of the change of circumstances on the existence of an obligation. The leading principle looking into this issue is the rebus sic stantibus principle. This principle can be considered as the opposite of the contemporary major contract rule worshipped by most of the European states and thus legal systems, the pacta sunt servanda principle. This principle, meaning the necessity of putting emphasis on the performance, is at present the fundamental principle of contract law of the Czech republic too. However, day-to-day life creates situations, in which the strict compliance with this principle can be in conradiction with justice and the contractor's expectations of the fairness of the law. The rebus sic stantibus principle is presently applied usually only to rare specific cases, the question, whether it should be allowed to terminate the contract under a essential change of the circumstances to all contracts in general, is an object of long-term discussions among many legal experts and legislators. This thesis is composed of five chapters, each of them dealing with different aspects of the essentialy changed circumstances (also...
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Principles of private law
Andraško, Richard ; Dvořák, Jan (advisor) ; Elischer, David (referee)
Principles of private law The reason of choosing "Principles of private law" for my thesis is that private law is built on untouchable values. For example, basic values like freedom and equality, which are represented by these principles. Many of them are indispensable in the relation of functionality of the whole system of law. Most of them have Roman law origin. The purpose of my thesis is to describe and summarize the main principles of private law that mostly appear in Czech law, especially in civil law. It also examines the influence of re-codification of private law on these principles and relationship between them. The thesis is composed of two parts. Part one, named general part, is introductory and defines different meanings of principles of law in Czech jurisprudence. It deals with historical perspective (Roman law connections to principles of law) and philosophical context (represented by concepts of legal positivism, theory of natural rights and sociological concept of law) of principles of law. It also describes the theory of principles of law by Ronald Dworkin. Part two, named specific part, focuses on principles of private law and contains the overview of them. It deals with legal regulations of these principles and their definitions according to judicial decisions. It also examines...
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Contractual Acquisition of Property
Faltová, Nikola ; Dvořák, Jan (advisor) ; Elischer, David (referee)
This thesis "Contractual acquisition of ownership" deals with the fundamental questions of contractual acquisition of property law in the Czech Civil Code. Some of the parts of the project are comparative. The author takes into account both the older national regulations of contractual acquisition as well as the different approaches in the same field in some foreign legal systems. In the introduction the author highlights the importance of property law (this right forms one of three fundamental pillars of private law - together with "man" and "contract") as well as the possibility to transfer it to another. First chapter shows that - from the general point of view - acquisition of property law as such may be based on a number of different modes. The paper contains an overview of particular modes and its dividing into relevant categories. The acquisition based on contracts is a type of derivative acquisition. Next chapter is devoted to some general questions of contractual transfer of ownership. Some decisive (general and special) legal principles are offered: namely the principle of the autonomy of the will, the principle of the absence of formality of contracts and finally the "nemo dat" principle (nemo dat quod non habet). This part of the project also focuses on the basic conceptual elements of...
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The institution of pre-contract liability in theory and practice
Kraus, Radek ; Elischer, David (advisor) ; Dvořák, Jan (referee)
Diese Arbeit behandelt das Thema "Rechtsinstitut der vorvertraglichen Haftung in Theorie und Praxis". Die ganze Arbeit ist in drei Teile gegliedert und zwar "Der Begriff der Vorvertraglichen Haftung", "Die Komparative Analyse der ausländischen Rechtsordnungen" und "Das tschechische Konzept der vorvertraglichen Haftung". Das Hauptziel dieser Arbeit ist, die praktischen Aspekte der vorvertraglichen Haftung zu beschreiben, was aber ohne ausreichende theoretische Grundlagen unmöglich ist. Die Doktrin culpa in contrahendo (Verschulden beim Vertragsabschluss) wird Rudolph von Jhering zugeschrieben, denn er hat im Jahre 1861 als erstes die charakteristischen Züge der vorvertraglichen Obligationen beschrieben. Der Autor ordnet in dem ersten Teil dieser Arbeit noch die vorvertragliche Haftung in das Rechtssystem ein. Die zum Teil von dem Autor entworfene Definition dient dann in dem zweiten und dritten Teil zu dem einfacheren Vergleich der Konzepte von vorvertraglicher Haftung in verschiedenen Rechtsordnungen. In dem zweiten Teil wird zuerst das deutsche Konzept der culpa in contrahendo beschrieben, wie es sich von R. von Jhering über die Schuldrechtsmodernisierung bis zum heutigen Tag entwickelt hat. Die Entwicklung der deutschen Auffassung der vorvertraglichen Haftung von der materiellen zur formalen...
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Characterisation of recombinant cathepsins B of the bird schistosome Trichobilharzia regenti
Dvořáková, Hana ; Mikeš, Libor (advisor) ; Dvořák, Jan (referee)
This study focuses on the recombinant cysteine peptidases - cathepsin B originating in the bird schistosome Trichobilharzia regenti that is unique across the whole family for its ability to migrate through the nerve tissue to the final localization. For invasion, migration, degradation of nutritional proteins and/or evasion of host immune responses, schistosome employs peptidases. This study follows the research done by researchers of Department of parasitology, Faculty of Natural Sciences, Charles University. The main goal of this study was to deepen the characteristics of recombinant cathepsins B originating in T. regenti. In T. regenti, two cysteine peptidases - cathepsins B1 (TrCB1) and B2 (TrCB2) - have been previously characterized. TrCB1 is located in the gut of schistosomula and involved in digestion. TrCB2 occurs in post-acetabular penetration glands of cercariae and probably facilitates penetration. The recombinant pro-cathepsin B (isoforms TrCB1.1, TrCB1.4 and also TrCB2) were expressed in Pichia pastoris yeast system. An attempt was made to produce in P. pastoris the recombinant isoform TrCB1.6, in which the active site cysteine is substituted by glycine. While TrCB2 underwent self-processing in the expression medium, TrCB1.1 and TrC1.4 zymogens were effectively activated only after the...
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