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Application for digital signature and timestamping
Remiaš, Miroslav ; Burda, Karel (referee) ; Lambertová, Petra (advisor)
In general, the Internet represents an unsecured medium of data transfer. Besides the rising popularity of the Internet, the matters of safety are getting to the foreground of importance. Anybody would be able to gain access to the computer network or to other valuable information if no algorithm of verifying the genuineness of identity were used. It is necessary to secure not only the access to the documents but also the content itself, which could be modified during the transfer through an unsecured medium. Last but not least, without the discretion provided by cryptography, the information may become literally public. To provide security and protection for the communicating participants the problems mentioned above are solved with the help of cryptographic techniques. The verification of the identity and the integrity of messages, the credibility of document’s ownership and safe data transfer through an unsecured medium are all the aspects, which the field of communication security on the Internet, thus the public key infrastructure, deals with. The electronic signature, as a part of the security area, is one of many advertised themes nowadays in Czech Republic. The aim of this master’s thesis is to acquaint the reader with the necessary technological procedures of digital signature, such as cryptographic techniques, public key infrastructure and timestamp. The practical part of this thesis consists of a suggested implementation of a web application in the programming language ASP.NET, which forms a certification authority with an opportunity of claiming a timestamp to authorize timestamps. After the problematic of cryptography was explained in the first chapter, the term of electronic signature has been introduced in the second chapter. Very important information, as far as the electronic signature of documents is concerned, is the time of the document’s creation and the subsequent signature verification by an appropriate authority. So the following part of the thesis is dedicated to the timestamp and to the authority of its verification. The fourth section deals with the large scale of public key infrastructure. The fifth part focuses on the description of the support for the whole problem mentioned so far using Microsoft’s programming language ASP.NET. The final sixth chapter represents the practical part of the thesis, namely the web application itself, where the individual modules of the application with its functions are described.
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Infrastructure of public keys
Bědajánek, Ondřej ; Malý, Jan (referee) ; Pust, Radim (advisor)
The subject of my thesis dscribes function and principles of the public key infrastructure as well as certificate authority. Under the operation system Linux was created self signed certificate authority. Web interface was devoloped in PHP for the purpose of the generation, distribution and rejection certificates. Configuration files for OpenVPN are included in the thesis and wireless security is achived by OpenVPN.
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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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Secure peer-to-peer communication system
Eliáš, Luboš ; Koutný, Martin (referee) ; Cvrk, Lubomír (advisor)
The main aim of this master's thesis is to implement a common, secure and peer-to-peer communication system. The system has ability to automatically establish and run a secure end-to-end connection. It has this ability even if a network address translator is in the way to the destination system, without need of any explicit configuration of this translator. The security procedures of this system are in a transparent manner masked from individual applications, which had to solve this challenge in their own way. A responsibility for a security is delegate to an application-independent subsystem working within the core of an operating system. The security of this subsystem is based on capturing the outbound and inbound IP packets and their authentication and encryption. The system was successfully implemented in MS Windows XP operating system, in programming language C++. Transfer rate of communication tunnel in different network bandwidth speeds was measured. Result shows, that in the case of use the system on standard PC sold nowadays is practically no decrease of the transfer rate in comparison to a common channel.
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MHP application
Holík, Tomáš ; Říha, Kamil (referee) ; Číka, Petr (advisor)
This Master Thesis is engaged in designing an interactive application for online betting in the DVB-T environment. The application is determined to running at Multimedia Home Plattform MHP and it allowes digital television viewers to make a bet on a sport match broadcasted on the television. The whole application is written in the Java language. All the information about users and the match are stored in a MySQL database, which is accessible through a php script placed on the server with the database. The applicaton is running in a set-top box and communicates with the script through the set-top box return channel. The channel between the server and the script is unsecure, so the communication has to be encrypted. The encryption process uses a symmetric-key cipher AES, which uses a shared secret key for encryption and decryption. Each application generates its own pseuodorandom and crypthographicaly strong AES key and sends it to the server. To secure the secret key transsmision is used the public-key cipher RSA.
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Cryptography and implementation in Notes and Domino
Klusoňová, Eva ; Karakhalil, Mourad (referee) ; Ošmera, Pavel (advisor)
This bachelor's thesis deals with description of cryptography and Public Key Infrastructure in Lotus Notes/Domino. The goal of this thesis is to give a brief overview of cryptographic techniques including their implementation in Lotus Notes/Domino and to propose an appropriate examples for demonstration and education in cryptographic techniques. In order to demonstrate selected algorithms an open-source e-learning software CrypTool is used.
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Implementation of AES Algorithm on FPGA
Smékal, D.
This paper presents a VHDL (Very High Speed Integrated Circuit Hardware Description Language) implementation of 128-bit AES (Advanced Encryption Standard) on FPGA card (FieldProgrammable Gate Array) using Virtex-7 FPGA chip manufactured by Xilinx company. In this project our main concern is to implement all modules of this algorithm on hardware.
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The Analysis of Security and Anonymity in Cryptocurrency Payments
Maňák, Michal ; Šebesta, Michal (advisor) ; Bruckner, Tomáš (referee)
Bitcoin and other cryptocurrencies are getting into common usage more and more frequently. Unfortunately this spread is connected with attempts to misuse their principles for personal benefit. The goal of this thesis is to explain the main principles of using bitcoin in relation to the internet identity. This connection is represented by two sources in the thesis: the first is a bitcoin blockchain, the second is the sum of various user profiles used in discussion forums and similar websites. The aim is to create and explain the process how to, by using the combination of this two sources, reveal the identity of a human using cryptocurrencies for payment (from a private person point of view). First, methods used for extraction of correct and useful data from the blockchain and internet profiles must be developed to be able to mine data from the joint database, merging into a full user profile containing personal data. Results of this investigation are extended by the rules of preserving anonymity on the internet, containing both technological and behavioural measures avoiding a share of personal data. The end of this thesis explains possible attack vectors that might be used for compromising cryptocurrencies. The methods of searching of the internet identity are a useful tool for facing these attacks.
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Analysis of digital currency Bitcoin
Huřťák, Petr ; Brixí, Radim (advisor) ; Kalina, Jaroslav (referee)
Bachelor's thesis is focused on digital currency Bitcoin, mainly on Bitcoin transactions and their attributes like speed, fees and safety. Main goals of this thesis are three, analysis of bitcoin buying possibilities in Czech Republic, comparison of Bitcoin transactions with common payment methods like bank transfers, credit card payment or PayPal, and analysis of number of merchants accepting bitcoin in time and discovery of trend from these data. This thesis is divided into theoretical and practical part. In theoretical part there are described basics of cryptography, which are necessary for understanding Bitcoin, and in depth description how Bitcoin works. Practical part is focused on fulfilment of described goals, besides that thesis is also addressing Bitcoin clients and comparison between most popular ones. Contribution of this bachelor's thesis is analysis of bitcoin buying possibilities in Czech Republic, comparing Bitcoin transactions with transactions of standard payment methods in terms of fees and time, and analysis of trend in number of merchants accepting bitcoin as one of the payment method.
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