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Microsoft Office Password Recovery Using GPU
Zobal, Lukáš ; Veselý, Vladimír (referee) ; Hranický, Radek (advisor)
This thesis describes the password recovery of Microsoft Office documents by expanding an existing tool Wrathion. The thesis explains the issue of digital document protection, modern encryption and hashing algorithms and rudiments of OpenCL standard. Next, the analysis of structure of MS Word, MS Excel and MS PowerPoint documents is performed, including all the versions since 1997. Using this knowledge, we create a draft and an implementation of improved DOC module for newer versions of the encryption, as well as a draft and an implementation of brand new modules for XLS and PPT formats and their newer variants DOCX, XLSX and PPTX. After that, we measure performance of the new modules and compare it with other competing password recovery tools.
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Cryptovirology
Kubík, Pavel ; Schäfer, Jiří (referee) ; Pecho, Peter (advisor)
This thesis is focused on a relatively new branch of computer security called Cryptovirology. It uses cryptography and its principles in conjunction with designing and writing malicious codes (e.g. computer viruses, trojan horses, worms). Techniques such as viral propagation through computer networks, capabilities of current viruses and similar threats are described. Beside cryptography and computer viruses, design of the cryptovirus and methods of a cryptoviral extortion attack along with their related potential are also analyzed below in this paper. As a proof of the concept in the given area of cryptovirology, a demonstrational computer program was written. The program was implemented with the respect to the satisfaction of the essentials set to the cryptovirus.
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Generation of Cryptographic Key from Eye Biometric Features
Semerád, Lukáš ; Hájek, Josef (referee) ; Drahanský, Martin (advisor)
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.
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Library of Algorithms for Text Ciphering
Vozák, Petr ; Řezníček, Ivo (referee) ; Kubíček, Radek (advisor)
p, li { white-space: pre-wrap; } p, li { white-space: pre-wrap; } This thesis deals with text ciphering. The presented paper describes at first basic theoretical background of cryptology and basic distribution of cryptographic algorithms. Then it describes a brief history of encryption from beginning to present. Theoretical description of ciphering methods and its implementation details are discussed here. All basic types of conventional encryption algorithms and also some modern ciphering methods are included; these are substitution, transposition, steganographic or combinations encryption systems. The result of this thesis is the library of algorithms for text ciphering in Java with a sample application, which demonstrates its funcionality.
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Implementation of Encryption Algorithms in VHDL Language
Kožený, Petr ; Martínek, Tomáš (referee) ; Kořenek, Jan (advisor)
This thesis deals with design and implementation of AES and DES encryption architectures for embedded systems. Architectures are implemented in VHDL language and design for FPGA technology. The proposed implementations are mapped on the Xilinx Spartan 3 technology. Both architectures are applied in simple ECB (Electronic Codebook) scheme with cache memories. A maximum throughput of design DES architecture 370 Mbps is achived with clock frequency of 104 MHz. The throughput of AES architecture at the maximum clock frequency of 118 MHz is 228 Mbps. Compared to software implementations for embedded systems, we achieve significantly higher throughput for both architectures.
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Message Encryption over Text Messengers for Android
Balvín, David ; Burget, Radek (referee) ; Kolář, Dušan (advisor)
The main purpose of this thesis is to design and implement an application that would handle encrypted communication using several protocols or existing applications. The application is able to handle automatic encryption using a symetric-key algorithm for sending messages and decryption on demand for receiving/reading messages. It also supports asymetric exchange of keys for symetric encryption. A simple user interface is also created for this application, taking ideas from default SMS application for Android and popular Messenger a Whatsapp.
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System of anonymous data collection
Troják, David ; Malina, Lukáš (referee) ; Dzurenda, Petr (advisor)
This thesis deals with contemporary approaches that provide higher protection of privacy of users. It focuses mainly on a group signature. In the practical part of this thesis I designed and implemented PS that is enable to gather information with the help of signal of a mobile device. The application was designed in accordance with fundamental cryptographic requirements such as the authenticity and the integrity of transmitted data. The anonymity of users is guaranteed through an application layer (the group signature) as well as through a network layer (Tor).
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Using Near-Field Communication (NFC) to Improve Messaging Privacy on Android OS
Karmazín, Jaromír ; Trchalík, Roman (referee) ; Očenášek, Pavel (advisor)
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.
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Web Services Security
Kubáni, Tomáš ; Doležel, Radek (referee) ; Malina, Lukáš (advisor)
The bachelor thesis analyzes the current state of Web services and their security. The first chapter describes the construction details, options and features web services, with primary focus on the technologies (SOAP, XML, HTTP, WSDL, etc.) used for communicating and processing information and resources. The most important part of this work is focused on cryptography and security for these services. The essence of cryptography and encryption methods is explained, the main safety requirements and security mechanisms is pointed out, security standards are presented and compared. Finally, the bachelor thesis contains the theoretical and practical proposal of our secure Web Service, according to selected and necessary criteria.
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