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Efficient Digital Signature Schemes
Varga, Ondrej ; Sobotka, Jiří (oponent) ; Malina, Lukáš (vedoucí práce)
Digital signatures, which take the properties of classical signatures, are used to secure the actual content of documents, which can be modified during transmission over an insecure channel. The problems of security and protection of communicating participants are solved by cryptographic techniques. Identity verification, message integrity, credibility, the ownership of documents, and the secure transmission of information over an unsecured channel, are all dealt with in secure communications - Public Key Infrastructure, which uses digital signatures. Nowadays digital signatures are often used to secure data in communication over an unsecured channel. The aim of the following master’s thesis is to familiarize readers with the necessary technological aspects of digital signatures, as well as their advantages and disadvantages. By the time digital signatures are being used they will have to be improved and modified to be secure against more sophisticated attacks. In this paper, proposals of new efficient digital signature schemes and their comparison with current ones are described. Also are examined their implications for computationally weak devices, or deployment in low speed channel transmission systems. After an explanation of cryptography and a description of its basic subjects, digital signatures are introduced. The first chapter describes the possible formatting and architecture of the digital signature. The second part of this master’s thesis is about current digital signature schemes and their properties. Chapter 3 describes some proposals of new efficient digital signature schemes and their comparison to those currently in use. In the practical part, the implementations (in the environment .NET in C#) of two effective digital signature schemes as part of a client-server application are presented and described (Chapter 4). In the last chapter the comparison and analysis of the implemented signature schemes are provided.
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Specifics of and differences in the development of server applications on the JavaSE and .NET platforms
Varga, Ondrej ; Pfeifer, Václav (oponent) ; Kovář, Petr (vedoucí práce)
Nowadays, in this modern world full of technology, it would be very difficult to find someone, who could live without using the computer. The computer applications are made by the always developing programming languages. The one of the newest and the most modern platforms are the JavaSE and the .NET, which two I needed to use for this bachelor's thesis. The newest developing platforms can be used in a lot of section of computer programs, in the network applications as well. Some classes dealing with exactly this section are implemented in them. Some of the commands are already programmed in these classes, so it helps to be easier our job at programming an application like this. Nowadays, a very frequently used network application is the FTP server, which uses FTP (File Transfer Protocol) for the communication with the client. It is a well established internet protocol defined for transfer data (and information about files) thorough computer networks, which uses TCP. Goal of this bachelor's thesis is to check abilities of development of the server side of the network applications on the JavaSE and .NET platforms. It means, to develop an FTP server application on both platforms, which includes the basic services, and after programming this network application resume the pros and cons of the used platforms. Chapter 1 describes the theory of platform JavaSE, developing language Java and used developing environment NetBeans. Properties of platform .NET, developing language C# and developing environment Visual Studio are described in chapter 2. Chapter 3 contests the realization of the practical part of the layout. Next chapter includes the basics of networking and the general characteristic of the FTP. In the last chapter are all the achievements and knowledge.
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Hybridní doporučování pro doménu knih
Varga, Ondřej ; Peška, Ladislav (vedoucí práce) ; Dokoupil, Patrik (oponent)
Bakalářská práce se zabývá tématem doporučovacích systémů, které jsou důležité zejména v e-commerce oblasti. Hlavním cílem práce bylo implementovat doporučovací systém, který by pokrýval potřeby doporučování v knižní doméně (na e-shopu zabýva- jící se prodejem knih). Těžištěm práce je implementovaný doporučovací systém, který zpracovává data dostupná pro doménu knih, nicméně je navržen obecněji tak, aby bylo možné jeho nasazení jako Recommendation-as-a-Service. Systém obsahuje jak samotné doporučovací algoritmy (kolaborativní, content-based i hybridní), tak i podporu pro jed- notlivé fáze životního cyklu doporučovaní, monitorování výkonosti doporučení a snadnou administraci pomocí interaktivního webového rozhraní. Doporučovací algoritmy jsme následně vyhodnotili, přičemž z experimentů plyne, že kolaborativní metody, zejména ALS faktorizace matic a ELSA, dosahují lepších výsledků s ohledem na metriky relevance. Nicméně hybridní přístupy a content-based metody mohou mít výhody, co se týká metrik nad rámec přesnosti, zejména Coverage a Novelty. 1
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Specifics of and differences in the development of server applications on the JavaSE and .NET platforms
Varga, Ondrej ; Pfeifer, Václav (oponent) ; Kovář, Petr (vedoucí práce)
Nowadays, in this modern world full of technology, it would be very difficult to find someone, who could live without using the computer. The computer applications are made by the always developing programming languages. The one of the newest and the most modern platforms are the JavaSE and the .NET, which two I needed to use for this bachelor's thesis. The newest developing platforms can be used in a lot of section of computer programs, in the network applications as well. Some classes dealing with exactly this section are implemented in them. Some of the commands are already programmed in these classes, so it helps to be easier our job at programming an application like this. Nowadays, a very frequently used network application is the FTP server, which uses FTP (File Transfer Protocol) for the communication with the client. It is a well established internet protocol defined for transfer data (and information about files) thorough computer networks, which uses TCP. Goal of this bachelor's thesis is to check abilities of development of the server side of the network applications on the JavaSE and .NET platforms. It means, to develop an FTP server application on both platforms, which includes the basic services, and after programming this network application resume the pros and cons of the used platforms. Chapter 1 describes the theory of platform JavaSE, developing language Java and used developing environment NetBeans. Properties of platform .NET, developing language C# and developing environment Visual Studio are described in chapter 2. Chapter 3 contests the realization of the practical part of the layout. Next chapter includes the basics of networking and the general characteristic of the FTP. In the last chapter are all the achievements and knowledge.
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Efficient Digital Signature Schemes
Varga, Ondrej ; Sobotka, Jiří (oponent) ; Malina, Lukáš (vedoucí práce)
Digital signatures, which take the properties of classical signatures, are used to secure the actual content of documents, which can be modified during transmission over an insecure channel. The problems of security and protection of communicating participants are solved by cryptographic techniques. Identity verification, message integrity, credibility, the ownership of documents, and the secure transmission of information over an unsecured channel, are all dealt with in secure communications - Public Key Infrastructure, which uses digital signatures. Nowadays digital signatures are often used to secure data in communication over an unsecured channel. The aim of the following master’s thesis is to familiarize readers with the necessary technological aspects of digital signatures, as well as their advantages and disadvantages. By the time digital signatures are being used they will have to be improved and modified to be secure against more sophisticated attacks. In this paper, proposals of new efficient digital signature schemes and their comparison with current ones are described. Also are examined their implications for computationally weak devices, or deployment in low speed channel transmission systems. After an explanation of cryptography and a description of its basic subjects, digital signatures are introduced. The first chapter describes the possible formatting and architecture of the digital signature. The second part of this master’s thesis is about current digital signature schemes and their properties. Chapter 3 describes some proposals of new efficient digital signature schemes and their comparison to those currently in use. In the practical part, the implementations (in the environment .NET in C#) of two effective digital signature schemes as part of a client-server application are presented and described (Chapter 4). In the last chapter the comparison and analysis of the implemented signature schemes are provided.
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