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Linear Cryptoanalysis
Kopko, Jan ; Hanáček, Petr (referee) ; Cvrček, Daniel (advisor)
This paper discusses one of possible attacks on block ciphers - linear cryptanalysis. In the beginning of this paper a basic structure of block cipher is presented, as well as concrete cipher on which the linear cryptanalysis is presented. After that basic principles of linear cryptanalysis and a preview of attack on this cipher follow.
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Software support for cryptography education
Stančík, Peter ; Vyoral, Josef (referee) ; Burda, Karel (advisor)
The main aim of this thesis was to study, choose and decribe techniques eligible for cryptography education. A pedagogically appropriate presentation for the selected techniques' principles was to be chosen. Another goal was to create an integrated modular web interface containing a calculator focused on cryptographic operations. The eligibility of techniques was assessed accordingly to the computing processes implied by these techniques and also accordingly to the ability of being presented in an illustrative way. A program simplifying calculations used in symetric and asymetric cryptography was designed and implemented. It disposes of a web interface and one of its parts is focused on steganographic techniques. On the other hand, any pedagogically appropriate presentation interconnecting this program with theoretical findings from this field was not found.
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Power side channel
Zapletal, Ondřej ; Mácha, Tomáš (referee) ; Martinásek, Zdeněk (advisor)
This thesis deals with side-channel cryptoanalysis. It is focused on power side-channel attack on cryptographic device. The microcontroller PIC is used as the cryptographic device. This microcontroller performs encryption through the symmetrical algorithm AES. For the purpose of simple and differential power analysis, we designed and constructed an experimental printed circuit board. The power consumption of the microcontroller PIC working with instruction AddRoundKey and SubBytes was scanned by a Tektronix CT-6 current probe. Data obtained by measuring were processed on the computer with relevant software and provided important information about the encryption key that was used.
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Lego Technic encryption demonstrator
Jančík, Jakub ; Malina, Lukáš (referee) ; Hajný, Jan (advisor)
The bachelor thesis is mostly about mechanical encryption. Primary task was to build demonstrator encryptor using only LEGO Technic building kit, which would allow polyalphabetical substitution encryption. The theoretical part includes information about origins of steganography, cryptography and cryptanalysis, it explains the process of the polyalphabetical substitution encryption and it will introduce Enigma – how it went on during development, on what principle it works and thanks to what it stopped being safe. Device was extended with LEGO MINDSTORMS which allowed to build the Enigma demonstrator.
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Safe Cryptography Algorithms
Mahdal, Jakub ; Hanáček, Petr (referee) ; Chmelař, Petr (advisor)
This thesis brings a reader an overview about historical and modern world of cryptographic methods, as well evaluates actual state of cryptographic algorithm progressions, which are used in applications nowadays. The aim of the work describes common symmetric, asymmetric encryption methods, cryptographic hash functions and as well pseudorandom number generators, authentication protocols and protocols for building VPNs. This document also shows the basics of the successful modern cryptanalysis and reveals algorithms that shouldn't be used and which algorithms are vulnerable. The reader will be also recommended an overview of cryptographic algorithms that are expected to stay safe in the future.
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Portal for the support of cryptography instruction
Forman, Tomáš ; Doležel, Radek (referee) ; Zeman, Václav (advisor)
The main goal of this master's thesis is building of web portal for presentation basic cryptography algorithms. Those algorithms would be explained in the theoretical page in the first place. After that, they would be demonstrated by scripts. One part of this project is designing simplified theoretical element for basic impletion portal of information. Next part is creating web portal by one of the free available CMS´s systems. Programming language JAVA would be used as an instrument for creating demonstration scripts. For creating animations will be used the Flash animation tool. Target of formed web portal is creating community of expert public. It would make new articles, scripts and knowledge. This way, the portal would be kept current. The section which would include failure the most widely used algorithms and instructions how to eliminate it will be part of portal.
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Side channels in cryptography
Budík, Lukáš ; Sobotka, Jiří (referee) ; Martinásek, Zdeněk (advisor)
This work deals with a problem called sidelong cannals in cryptografy. First part describes basic segmentation of cryptografy branch. In addition to this the document mentions some requirements for cryptology system from security angle. In another section basic algorithms and protocols are described which are used in cryptology. Main part of this work is aimed at sidelong cannals problem. Conclusion of this task demonstrates an attack by time-side canal to algorithm RSA.
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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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Safe Cryptography Algorithms
Zbránek, Lukáš ; Schäfer, Jiří (referee) ; Chmelař, Petr (advisor)
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.
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Security of data stored on the hard disk
Polášková, Markéta ; Hajný, Jan (referee) ; Martinásek, Zdeněk (advisor)
This work is dedicated to the security of data stored on the hard drive of your computer and using encryption. The first part explains the basic concepts of cryptography and describes her in history. In other chapters, this work is dedicated to a description of the side channels and attacks on these channels. How can the attacker obtain information from a cryptographic module. The following section describes the types of encryption they use nowadays and what are their weaknesses. Bachelor thesis continues with examples of individual encryption programs and device ICZ Protect Boot. The last part deals with resistance testing on equipment ICZ Protect Boot. Testing of resistance to flow analysis using a side channel. Finally, bachelor thesis deals with the analysis of communication between the computer and ICZ Protect Boot.
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