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Historical encryption procedures and their application
MILICHOVSKÁ, Eva
I deal with historical encryption procedures and with their application in teaching in my diploma thesis. I present a brief list of some encryption methods in following chapters which were used from antiquity to the mid-20th century. There are prepared specific worksheets for encryption and decryption in this thesis. For several ciphers, the required tools are included in this work, too.
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The use of cryptographic algorithms and their real use.
Chrstoš, Tomáš ; Holý, Radek (advisor) ; Kaliková, Jana (referee)
The aim of this work is to compare some methods of file encryption. The main goal is to select the most suitable algorithm selected on the basis of their testing and comparing the algorithms. Another goal is to refer about cryptography itself, its history and its development. The theoretical part is first outlined the historical development of cryptography. In addition, this section analyzed and described theoretically selected ciphers, including modern and principles of their functioning. In the practical part, these encryption methods are compared for selected files in their suitability for a particular file type (video data, audio files, documents). These ciphers are tested to encrypt files and decrypt files.
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Library of Algorithms for Text Ciphering
Mikulka, Jiří ; Havel, Jiří (referee) ; Kubíček, Radek (advisor)
This thesis brings an overview of historical and modern methods and approaches used in cryptography. It also describes and assesses ciphers, which have been used since the very beginning of encryption till modern ciphers. Based on information resulting from this overview the reader should be able to distinguish between ciphers, know their advantages and disadvantages, and be able to choose the best cipher for any purpose. Ciphers mentioned in this thesis are implemented in a library called CipherLib , which shows usage of every described cipher.
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AES Tolerance to Timing Analysis
Ondruš, Juraj ; Matyáš, Václav (referee) ; Cvrček, Daniel (advisor)
This thesis deals with timing analysis of the AES (Advanced Encryption Standard). The design of {\em Rijndael\/}, which is the AES algorithm, is described here. For the side channel attacks is necessary to know the principles of the cache memory in CPU and its architecture. In this thesis are involved major security problems of AES which can be used for successful attacks. Several different implementations of AES are discussed too. Several types of timing attaks are also described. According to the experimentations these attacks should be efficient to the most presently used AES implementations. Finally, the results of this work are described, possible countermeasures against this attack and motions for the next research.
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Analysis of data transfer security issues at particular OSI model layers
Kňazovický, Pavel ; Růčka, Lukáš (referee) ; Sobotka, Jiří (advisor)
The aim of this Bachelor's thesis is the analysis of secured data transfer protocols. The very first part is dedicated to the short description of the reference model ISO/OSI. The second one is focused to the secured protocols at particular layers of ISO/OSI model, of which SSL/TLS protocol is closely analysed in the third part. The last part is about often used attacks in the area of computer networks and their services and the basic protection against them is also mentioned.
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Cryptographic methods of data security
Miloš, Jiří ; Koutný, Martin (referee) ; Lambertová, Petra (advisor)
Bachelor‘s thesis on theme Cryptographic methods of data security consists of three parts. In first part are itemized general theoretical principles, which employs in these sphere. There are also mentioned not only contemporaneous but historical cryptographic standards or algorithms. The second part of these bachelor‘s thesis refer to a possibility of breaking these standards. There are described most applied cryptoanalytics principes and their practical using, especially in the sphere of computer networks and their services. The final part contains a description of the development of simple computer application, which demonstrates the use cryptographic methods in the security packages in personal computer.
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Distributed systems for cryptoanalysis
Vašek, Jiří ; Trzos, Michal (referee) ; Sobotka, Jiří (advisor)
This thesis should introduce a reader with basic objectives of parallel computing followed by distributed systems. The thesis is also aimed at description of cryptographic attacks. The main point should be to obtain theoretic information for design of distributed system for cryptoanalysis.
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Side channel attacks
Popovský, Michal ; Sobotka, Jiří (referee) ; Martinásek, Zdeněk (advisor)
It is very difficult in real-time breaking the cryptographic algorithms used at present. The Classical cryptoanalysis is based on finding weaknesses in the mathematical structure of the algorithm. Discovery of side channels caused a substantial change in this science. Side-channel attacks are based on incorrect physical implementation of cryptographic algorithms. This new way attack changes notions about cryptography and security of systems. This master´s thesis contains a detailed description of the whole problem of side channels and deals with side-channel attacks on the RSA asymmetric algorithm. This thesis includes the design and realization of laboratory exercise, which is focused on the time attack on the RSA algorithm implementation.
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Design of hardware cipher module
Bayer, Tomáš ; Stančík, Peter (referee) ; Sobotka, Jiří (advisor)
This diploma’s thesis discourses the cryptographic systems and ciphers, whose function, usage and practical implementation are analysed. In the first chapter basic cryptographic terms, symmetric and asymetric cryptographic algorithms and are mentioned. Also usage and reliability are analysed. Following chapters mention substitution, transposition, block and stream ciphers, which are elementary for most cryptographic algorithms. There are also mentioned the modes, which the ciphers work in. In the fourth chapter are described the principles of some chosen cryptographic algorithms. The objective is to make clear the essence of the algorithms’ behavior. When describing some more difficult algorithms the block scheme is added. At the end of each algorithm’s description the example of practical usage is written. The chapter no. five discusses the hardware implementation. Hardware and software implementation is compared from the practical point of view. Several design instruments are described and different hardware design programming languages with their progress, advantages and disadvantages are mentioned. Chapter six discourses the hardware implementation design of chosen ciphers. Concretely the design of stream cipher with pseudo-random sequence generator is designed in VHDL and also in Matlab. As the second design was chosen the block cipher GOST, which was designed in VHDL too. Both designs were tested and verified and then the results were summarized.
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Analysis of attacks on asymmetric cryptosystems
Tvaroh, Tomáš ; Ivánek, Jiří (advisor) ; Palovský, Radomír (referee)
This thesis analyzes various attacks on underlying computational problem of asymmetric cryptosystems. First part introduces two of the most used problems asymmetric cryptography is based on, which are integer factorization and computation of discrete logarithm. Algorithms for solving these problems are described and for each of them there is a discussion about when the use of this particular algorithm is appropriate and when it isn't. In the next part computational problems are related to algorithms RSA and ECC and it is shown, how solving the underlying problem enables us to crack the cypher. As a part of this thesis an application was developed that measures the efficiency of described attacks and by providing easy-to-understand enumeration of algorithm's steps it can be used to demonstrate how the attack works. Based on the results of performed analysis, most secure asymmetric cryptosystem is selected along with some recommendations regarding key pair generation.
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