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Software support for cryptography system training based on discrete logarithm
Kříž, Jiří ; Zeman, Václav (referee) ; Burda, Karel (advisor)
Current needs of human communication came to status, when most of transferred messages are considered as private and transition over non-secured communication lines in open form is not possible. That originated a lot of different methods for securing of messages and transfers in ciphered form. Two mainstreams were established, symmetric cryptography and asymmetric cryptography. Second of mentioned groups is based on usage of two information – keys, when one of then is broadly known and is public and second, well protected and private. Using a public key it is possible to establish a cryptogram of message, but for deciphering it is necessary to know private key. Asymmetric methods are based on mathematical problems, for which there is not an effective computing algorithm. This thesis are focused for asymmetric cryptosystems based on discrete logarithm problem, where ciphering of message using public key is very easy and quick, but deciphering without knowledge of private key is extremely time consuming process. Work describes a mathematical base of discrete logarithm problem, its’ properties and methods developed for solving of this problem. Descriptions of particular cryptosystems are given, i.e. ElGamal cryptosystem, Diffie-Hellman protocol and DSA. Second part of thesis is focused for web application developed as study support of discrete logarithm problem and of cryptosystems using this problem. It describes functional and graphical interface, work with it and options given to user working with application. Mentions also lessons for user which should help with understanding of described problems and practicing.
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Slow DoS attacks generator
Krivulčík, Andrej ; Zeman, Václav (referee) ; Sikora, Marek (advisor)
The work is focused on Slow DoS attacks and generating them. There are compared 3 most popular web servers and their defensive modules against this type of attacks. Closed are described network model TCP/IP, protocol HTTP (Hypertext Transfer Protocol), each DoS attack, Slow GET, Slow POST or Slow Read and also flood attacks. Afterwards the attack generator is described, with its functionality.
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Queueing theory utilization in packet network design and optimization process
Rýzner, Zdeněk ; Zeman, Václav (referee) ; Novotný, Vít (advisor)
This master's thesis deals with queueing theory and its application in designing node models in packet-switched network. There are described general principles of designing queueing theory models and its mathematical background. Further simulator of packet delay in network was created. This application implements two described models - M/M/1 and M/G/1. Application can be used for simulating network nodes and obtaining basic network characteristics like packet delay or packet loss. Next, lab exercise was created, in that exercise students familiarize themselves with basic concepts of queueing theory and examine both analytical and simulation approach to solving queueing systems.
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I2C-RS232 converter
Bednařík, Martin ; Zezula, Radek (referee) ; Zeman, Václav (advisor)
The objective of this thesis is to get familiar with function of I2C bus and microcontrollers AVR and study the principle of connecting microcontroller with the other circuits via this bus. Another goal is to design a device which will enable a communication between personal computer and controlled circuits. A part of this project is production of necessary microcontroller software equipment and to develop own communication protocol. Another output of this project is getting an overview of applied technologies, study possibili-ties of their additional usage and potential enlargement of device with another components.
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Digital identity
Dvořák, Roman ; Burda, Karel (referee) ; Zeman, Václav (advisor)
This bachelor‘s thesis deals with the personal digital identity area. Its goal is to describe accompanying technologies which ensure the course of this field. In addition, another goal is to describe the state of things in related sectors. At first, attention is focused to basic concepts and terms describing this topic. The following section describes technologies which are used in area of digital and bank identity. In the next chapter, the emphasis is on explaining terms linked with digital identity and the structure of public eGovernment, followed by the description of e-identity. In this chapter, the identification means, provided by the government or commercial sector, are more explained. The same applies to the identification means provided by the government, but which are not considered as e-identity. Another chapter is dedicated to European Digital Identity and its current state, followed by mentioning states which have used digital identity before it was made mandatory by the regulation from European Commission. The following chapter explores security threats, their enumeration and classification according to different criteria. It mentions types of cyberattacks, threats associated with using digital identity and elimination of the threats. The point of view is taken from user’s experience, but from providers as well. The last chapter describes the practical part which is an educational web application that summarizes the output of this bachelor’s thesis.
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