The main topic of the thesis is creation of formulas for the amount of information entropy in biometric characteristics of iris and retina. This field of science in biometrics named above is unstudied yet, so the thesis tries to initiate research in this direction. The thesis also discusses the historical context of security and identification fields according to biometric characteristics of a human being with an overlap for potential usage in biometrics of iris and retina. The Daugman’s algorithm for converting iris image into the binary code which can be used as a cryptographic key is discussed in detail. An application implementing this conversion is also a part of the thesis.

Confidential information such as passwords, cryptographic keys, certificates, etc. are used every day on various places. Mobile phone can be a good storage for such informations, but is necessary to ensure data security. Main goal of this project is to create a program for Windows Mobile phones which will keep all the informations in one place protected by password. Designed program lets user to store passwords, cryptographic keys, various files, important contacts, credit card numbers, etc. Some of the stored informations can be downloaded from remote server via FTP protocol or from smart card. It is also possible that two clients will synchronize their informations via Network and other usefull functions.

V této práci vytváříme jednoduchý systém pro rychlou textovou komunikaci (IM), který využívá technologii Near-Field Communication (NFC) ke zlepšení bezpečnosti a soukromí. V první části zkoumáme samotnou technologii NFC. Poté se věnujeme možnostem NFC v operačním systému Android pro chytrá mobilní zařízení a také existujícím aplikacím, které tyto možnosti využívají. Rovněž zkoumáme nejmodernější přístup k bezpečnému IM, zejména Signal Protocol a jeho open-source implementaci pro Android. Dále pak navrhujeme IM systém, který používá Signal Protocol pro šifrování zpráv a NFC pro výměnu kryptografického materiálu, aniž by vyžadoval použití telefonních čísel nebo důvěryhodnou třetí stranu. Nakonec předkládáme vzorovou implementaci klientské i serverové aplikace a zhodnocení vlastností tohoto systému z hlediska soukromí a bezpečí.

The dissertation thesis deals with cryptographic protocols for secure authentication of communicating parties, which are intended primarily for low-cost devices used in Internet of Things. Low-cost devices represent computationally, memory and power constrained devices. The thesis focuses mainly on the possibilities of using mathematically undemanding cryptographic resorces for ensuring integrity of transmitted dat, authenticity of and secured transmission of data on low-cost devices. The main goals of the thesis focus on the design of new advanced cryptographic protocols for ensuring integrity of transmitted data, authenticity, confidentiality of transmitted data between low-cost devices and authenticity with non-repudiation of done events. The thesis describes proposal of three authentication protocols, one unilateral authentication protocol and two mutual authentication protocols. The thesis also describes proposals of two protocols for secured transmission of data between two devices, one protocol without a proof of receipt data and one protocol with proof of receipt data. In this thesis is also performed a security analysis and a discussion to proposed protocols.

This master thesis deals with an implementation of Diffie-Hellman protocol on smart card which is based on MULTOS OS. Defines the smart cards based on MULTOS OS and their usage. Output of this thesis are applications for a smart card and for a client using Diffie-Hellman protocol for establishing of a secret key between two communication sides through unsecured communication channel.

Die Chemnitzer Linux-Tage sind eine Veranstaltung rund um das Thema Open Source. Im Jahr 2011 wurden 102 Vorträge und Workshops gehalten. Der Band enthält ausführliche Beiträge zu 12 Hauptvorträgen sowie Zusammenfassungen zu 78 weiteren Vorträgen. / The "Chemnitz Linux Days" is a conference that deals with Linux and Open Source Software. In 2011 102 talks and workshops were given. This volume contains papers of 12 main lectures and 78 abstracts (in german).

Master's thesis deals with issue of cookie-based central authentication services. Present-day methods of single sign-on are described. The specification of single sign-on mechanism Cosign and its authentication filter is closely viewed. Cryptographic algorithms needed by this filter are described, as well as their possible realization in PHP. Next, the implementation of Cosign authentication filter is described. Performance of the filter is tested and its future use is analysed.

In this thesis there is description of cryptographic algorithms. Their properties are being compared, weak and strong points and right usage of particular algorithms. The main topics are safeness of algorithms, their bugs and improvements and difficulty of breaching. As a complement to ciphers there are also hash functions taken in consideration. There are also showed the most common methods of cryptanalysis. As a practical application of described algorithms I analyze systems for secure data transfer SSH and SSL/TLS and demonstrate an attack on SSL connection. In conclusion there is recommendation of safe algorithms for further usage and safe parameters of SSH and SSL/TLS connections.

Focus of this thesis is to compare legislation of electronic signature in the Czech Republic and in the USA. In first chapter are explained basic terms, such as cryptography, certificate or certification authority. Next two chapters deal with laws concerning electronic communication. In chapter about Czech legislation they are electronic signature law and electronic transactions and authorized document conversion law. Moreover, Czech Republic has to abide EU directive. Chapter about USA legislation consists of ESIGN act and UETA. Following chapter is dedicated to problems caused by imperfect legislation. Last chapter contains evaluation of described legislation.

This master thesis deals with the implementation of variants of cryptographic libraries containing primitives for elliptic curves. By creating custom metering charts to compare each implementation. The main task was not only the implementation of libraries but also the design and implementation of test scenarios together with the creation of measurement methods for different libraries and hardware platforms. As a result, a number of experimental tests were conducted on different curves and their parameters so that the results of the work included complex problems of elliptic curves in cryptography. The main parameters were power, time and memory consumption.