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Digital Image Watermarking
Šujan, Miroslav ; Říha, Kamil (referee) ; Číka, Petr (advisor)
The bachelor´s thesis deals with the problem of static digital watermarking in frequency domain. It is a process of adding secret information to the original data without any negative influence to them, while in the same time making sure that the identification and hidden watermark cannot be removed easily. The main aim of this thesis is to sum up the current techniques of watermarking, to carry out of two watermarking techniques and a test of resistance to attacks against them.
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Network protection testing and DoS attacks protection
Hanzal, Jan ; Šilhavý, Pavel (referee) ; Hajný, Jan (advisor)
The aim of this Master thesis is a testing of Cisco ASA\,5510 firewall with affect of Denial of Service attacks. Part of the thesis is a teoretical description some of the attacks and practical tests. Practical part covers basic testing of Cisco ASA with Spirent Avalanche 3100B. Number of TCP connections per second and firewalls throughput on 7th layer of ISO/OSI model were tested. Also the effect of Denial of Service attacks on the throughput. In a next part there is described one possible way how to generate Denial of Service attacks from a Linux server to the firewall. Python scripts were used for generation DoS packets. With those scripts it is possible to generate five types of attacks.
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Using of the attack "Pass the hash attack" for the compromising of high privileged accounts.
Jakab, Vojtěch ; Rosenberg, Martin (referee) ; Babnič, Patrik (advisor)
The master thesis deals with the attack "‘pass the hash"’ on high privileged accounts. Within the theoretical part is discussed creating hashes and its use. Next is a descrip- tion of the authentication in Windows operating system. There are also pointed out weaknesses in the design of authentication mechanisms. The last part deals with the individual attack and security options for mitigating the impacts. In the practical part are tested available tools for retrieving hashes from the files of the operating systems and tools which allow the attack itself. The output of this section is selection of the appropriate tools to demonstrate the attack in a proposed real environ- ment. The last topic is about designing the experimental environment, demostration of the attack with the possibility of getting through the network. The last steps deal with mitigating the impact of the attack.
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Advanced Methods to Multimedia Data Protection
Mikulčík, Ondřej ; Zukal, Martin (referee) ; Číka, Petr (advisor)
To protect the the copyright of multimedia works have been developed watermarking techniques, that insert an invisible watermark to the original data. The aim of this thesis was to explore modern watermarking techniques, choose three of them and realize them. Also test them, evaluate their properties and possibly improve them. All methods insert a watermark into luminance component of the original image, and work with binary or black and white watermark. All techniques work in the frequency domain using discrete wavelet transform. For the implementation of methods, have been developed software named "Watermarking" that has been programmed in JAVA Version 7. The first chapter describes the types of watermarks, the general process of insertion and extraction, watermarking systems and important feature requests of embedded water- marks. In addition, qualitative methods are mentioned for their comparisons and testing. The chapter also contains a theoretical description of the used transformations and functions. In the second chapter is described the user interface of the software "Water- marking". Chapters three and four contain a theoretical description of the implemented methods and description of implementation of insertion and extraction processes of the watermark. Also there are discussed the exact procedures for testing, the sample data, and the results which are clearly displayed in the tables. The fifth chapter discusses in detail the results obtained in testing the robustness of the watermark, using the software StirMark. In the conclusion are evaluated the advantages and disadvantages of methods and quality parameters.
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Statistical anomaly detection methods of data communication
Woidig, Eduard ; Mangová, Marie (referee) ; Slavíček, Karel (advisor)
This thesis serves as a theoretical basis for a practical solution to the issue of the use of statistical methods for detecting anomalies in data traffic. The basic focus of anomaly detection data traffic is on the data attacks. Therefore, the main focus is the analysis of data attacks. Within the solving are data attacks sorted by protocols that attackers exploit for their own activities. Each section describes the protocol itself, its usage and behavior. For each protocol is gradually solved description of the attacks, including the methodology leading to the attack and penalties on an already compromised system or station. For the most serious attacks are outlined procedures for the detection and the potential defenses against them. These findings are summarized in the theoretical analysis, which should serve as a starting point for the practical part, which will be the analysis of real data traffic. The practical part is divided into several sections. The first of these describes the procedures for obtaining and preparing the samples to allow them to carry out further analysis. Further described herein are created scripts that are used for obtaining needed data from the recorded samples. These data are were analyzed in detail, using statistical methods such as time series and descriptive statistics. Subsequently acquired properties and monitored behavior is verified using artificial and real attacks, which is the original clean operation modified. Using a new analysis of the modified traffics compared with the original samples and an evaluation of whether it has been some kind of anomaly detected. The results and tracking are collectively summarized and evaluated in a separate chapter with a description of possible further attacks, which were not directly part of the test analysis.
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Distributed systems for cryptoanalysis
Vašek, Jiří ; Trzos, Michal (referee) ; Sobotka, Jiří (advisor)
This thesis should introduce a reader with basic objectives of parallel computing followed by distributed systems. The thesis is also aimed at description of cryptographic attacks. The main point should be to obtain theoretic information for design of distributed system for cryptoanalysis.
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Antivirus protection of a computer from a boot repository
Mlejnek, Jiří ; Malina, Lukáš (referee) ; Burda, Karel (advisor)
ABSTRACT Theme of the thesis is the design method of anti-virus protection with the use of an alternative boot store. Processed is a related issue of viruses and the possibility of defenses against them. This thesis is focused on the design and selection of components solutions enabling the execution of antivirus test from the undistorted by the operating system. With selected components continues to realize an alternative booting the operating system from a Windows platform computer network with automatic virus checking of all local disks. The results of inspection are transmitted using signed files on a network server and typically give an overview of the results of the individual tests.
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Side channels
Kolařík, Jan ; Sobotka, Jiří (referee) ; Martinásek, Zdeněk (advisor)
This Master Thesis deals with the side channels, AES encryption algorithm and the use of neural networks to obtain the encryption key. The first part of this work is focused on the basics of cryptography and attacks on cryptographic module. The second part is focused on electromagnetic side channel attack on PIC16F84A microcontroller with embedded AES algorithm. In this section, the Master Thesis tries to analyze electromagnetic emissions of operation S-Box in AES algorithm and try to find sensitive information to use neural network identify encryption key of the AES algorithm. In conclusion is described the software source code to determine the encryption key, summarized results and discussed ways to defend against electromagnetic side channel attack.
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Network attacks by Cain & Abel
Smékal, Lukáš ; Stančík, Peter (referee) ; Sobotka, Jiří (advisor)
This Master’s thesis is dealt in the local area network security, cryptographic algorithms, particular attacks on computer networks a practical application these attacks in local area networks. To application particular attacks is used the Cain & Abel program. The detailed manual for this program is created from the results of these attacks. This manual contains the exhibits of usage particular program tools and the attack application exhibits. This manual considers consequences of particular attacks and summarises achieved results during work with tools too. Master thesis closely deals with one of the program tools called RSA SecureID Token Calculator. Authentication via hardware tokens is contained in this Master thesis. Thesis contains the way of authentication using RSA SecureID Token Calculator without physical owning of the hardware token. Cain & Abel program shows and interprets why cashed passwords in operation system are dangerous and it shows methods how attacker can reveal this passwords from the operation system memory. This Master thesis is focused on sniffing credentials and passwords in local area networks and it is focused on cryptographic algorithms cracking for username and passwords revealing.
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Voice-over-IP principle and security problems
Bořuta, Petr ; Hošek, Jiří (referee) ; Vyoral, Josef (advisor)
This master’s thesis deals with security properties of protocols used for VoIP systems. In the first part, there is a description of most commonly used protocols and structure of VoIP systems. This part also discuss signaling and transport protocols. The second part of this paper describes techniques of ensuring quality of services. The next part presents SIP messages and communication. Last part of this paper overviews security risks of VoIP protocol. Practical part of this thesis describes creation of a testing VoIP network, on which several attacks has been made, fallowed by securing of mentioned VoIP network. Result of this thesis is evaluation of security risks connected to VoIP communication.
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