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Realization of attack on SHA-1 hash function
Dziura, Michal ; Hajný, Jan (referee) ; Malý, Jan (advisor)
The bachelor thesis is concerned with hash functions, SHA-1 function and its implementation in Java. The thesis describes weaknesses of this function and implements the implementation of the selected attack leading to the revelation of source text or attack based on targeted falsifying hash. This work also describes characteristics of hash functions, constructions and their use. The last part deals with a description of the attack on the hash function SHA-1 with the complexity of the 2^69.
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Network Anomaly Detection
Bartoš, Václav ; Kořenek, Jan (referee) ; Žádník, Martin (advisor)
This work studies systems and methods for anomaly detection in computer networks. At first, basic categories of network security systems and number of methods used for anomaly detection are briefly described. The core of the work is an optimization of the method based on detection of changes in distributions of packet features originally proposed by Lakhina et al. This method is described in detail and two optimizations of it are proposed -- first is focused to speed and memory efficiency, second improves its detection capabilities. Next, a software created to test these optimizations is briefly described and results of experiments on real data with artificially generated and also real anomalies are presented.
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Performance tests of cryptographic algorithms
Pospíšil, Karel ; Martinásek, Zdeněk (referee) ; Sobotka, Jiří (advisor)
Bachelor's thesis deals with analysis of the various cryptographic algorithms that are used for securing communications. The first part is devoted to symmetrical cryptographic algorithms, asymmetric cryptographic algorithms and hashing functions. The second part deals with the security classification and attacks that are used to attack cryptographic algorithms and hash function. The third part deals with the selected testing algorithm RC4 and MD5 hashed function for using CrypTool. The final section provides an evaluation and test results of algorithm RC4 and MD5 hashing function.
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Bitcoin Mining Acceleration
Novotný, Jan ; Veselý, Vladimír (referee) ; Kajan, Michal (advisor)
This master's thesis deals with virtual currency called Bitcoin. It describes the functioning of the currency of technical perspective especially the implementation of the transaction, the way of its validation and ensuring the integrity by using cryptographic functions. Furthermore, it describes the principle of the Bitcoin creation, particularly mining method called pooled mining. The thesis also describes the communication protocols and design of architecture to acceleration of the bitcoin mining. Finally, there are described tests, assessment and proposals for the continuation of work.
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Evolutionary Design of Hash Functions
Kidoň, Marek ; Bidlo, Michal (referee) ; Dobai, Roland (advisor)
Hash tables are fast associative array implementations which became part of modern world of information technology and thanks to its simplicity became very popular among computer programmers. The choice of proper hash function is very important. Improperly selected hash function can result in poor hash table performance and its application. Currently there are many exceptional implementations of general hash functions. Such functions are not constrained to a concrete set of inputs, they perform on any input. On the other hand if we know the input domain we can design a specific hash function for desired application thus reaching better levels of performance compare to a general hash function. However hash function design is not trivial. There are no rules, standards, guides nor automated tools that would help us with such a task. In case of manual design the hash function author has to rely on his/her knowledge, experience, inventiveness and intuition. In case of such complicated tasks there is sometimes advantageous to choose a different path and use techniques such as evolution algorithms. Natural computing is an approach of certain problem solutions that are inspired by the process of species reproduction as defined by Charles Darwin. In this thesis we will design hash functions for the domain of IP addresses, that serve as an unique network device interface identifier in internet protocol networks. The chosen subset of natural computing is the genetic programming, a very specific technique that is an adequate approach to our problem thanks to its properties. Evolutionary designed hash functions offer good properties. They outperform state-of-the-art generic, human-created hash functions in terms of speed and collision resistance.
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Secure communication in systems using restricted devices
Michálek, Tomáš ; Martinásek, Zdeněk (referee) ; Malina, Lukáš (advisor)
This thesis presents the usability and analysis of cryptographic methods on devices with low computing power and low memory capacity. The thesis describes different methods and shows examples of their usability in practice. According to certain parameters of security methods, such as code size and memory size it is selected and compared symetric ciphers and authentication codes. There are also described some security protocols and possible attacks. The next part includes a comparison of ciphers and chosen candidates are tested on our microcontroller. In the end there are propose, implemented and analyzed security protocols.
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Application for Demonstration of Hash Algorithms SHA-1 and SHA-2
Siska, Josef ; Petrlík, Jiří (referee) ; Novotňák, Jiří (advisor)
In this thesis, the theory related to the hash algorithms SHA-1 and SHA-2 is presented, along with a description of possible implementation of an application that demonstrates how these algorithms work. The first part of this thesis describes the principles of construction of hash functions, their use and history of selected hash functions. The two following chapters present conventions and algorithms of the SHA-1 and SHA-2. The next chapter describes the general concepts related to the attacks on the hash functions and selected attacks are presented in more detail. The last two chapters outline the design and implementation of an application that was created as part of this work. In the end the evaluation of results of this thesis and proposals for its possible continuation are presented.
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Cryptocurrencies
Šindelářová, Anna ; Haupt, Jaromír (referee) ; Smutný, Milan (advisor)
Tato bakalářská práce se zaměřuje na téma Kryptoměny. Práce se zabývá vznikem a vývojem kryptoměn, jejich využitím a popisem jejich základních principů fungování. Více podrobně jsou v této práci popsány 3 vybrané kryptoměny – Bitcoin, Ethereum a Monero. Cílem této práce je provést porovnání těchto vybraných kryptoměn, které je popsáno v poslední kapitole.
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Neural networks in cryptography
Borkovec, Tomáš ; Rášo, Ondřej (referee) ; Martinásek, Zdeněk (advisor)
Bachelor's thesis aims to introduce neural networks and their properties, which can be used for creating cryptographic protocols based on neural networks. It proposed concrete use of neural networks in cryptography and creates a teoretical basis for the practical implementation. In practical section is discusses the creation of neural network on which we based cryptographic model. The constructed models are then subjected to testing. At the close of the thesis we discussed the advantages and disadvantages of possible use in real cryptographic modules.
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Electronic Mail Room of the BUT
Beran, Martin ; Křena, Bohuslav (referee) ; Marušinec, Jaromír (advisor)
This dissertation thesis attends to problems of electronic registry for VUT. It deals with the principal of electronic registry functioning, electronic signature and it compares offer of the commercial registries. It goes in for the proposal and implementation of the electronic registry for VUT. Since the using of the e- registry on all public service Office was legalized the people can avoid long queues and the employees are avoided from the stress before dead lines. By the communication through the electronic registry is very important the electronical signature. It is almost a full-valued and lawful alternative to the physical signature. For its safety and utility this system employes asymmetric codes and hash algorithm. Presently in many states, where the electronical signature is legalized it is used together with standard X 509 which defines the format of certificates, organization and action of certification authorities. The certification autority ensures safe connection of the person and general key for using of the electronical signature.
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