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Concept of E-shop
Morávek, David ; Valenta, Jiří (referee) ; Dvořák, Jiří (advisor)
This thesis deals with a creation of a company´s electronic shopping. On the basis of the knowledge and information acquired from a theoretical part, the suggestion involves the best possibilities of electronic shopping that will lead to a stable and firm position on this kind of market, and to increase of the capital as well as the reputation of the company with potential customers.
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Bayesian Networks Applications
Chaloupka, David ; Rozman, Jaroslav (referee) ; Zbořil, František (advisor)
This master's thesis deals with possible applications of Bayesian networks. The theoretical part is mainly of mathematical nature. At first, we focus on general probability theory and later we move on to the theory of Bayesian networks and discuss approaches to inference and to model learning while providing explanations of pros and cons of these techniques. The practical part focuses on applications that demand learning a Bayesian network, both in terms of network parameters as well as structure. These applications include general benchmarks, usage of Bayesian networks for knowledge discovery regarding the causes of criminality and exploration of the possibility of using a Bayesian network as a spam filter.
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Proxy servers in Internet
Henek, Jan ; Burda, Karel (referee) ; Komosný, Dan (advisor)
The goal of this paper is to analyze the representation of proxy servers in cyber attacks conducted by Internet. For this purpose I used method which compares tested IP address with database of open proxy servers. I assembled a list of IP address taken from the blacklist of cyber attacks committed in 2015. Then I checked this list with the created program Proxy checker and compared them with a database of open proxy servers. By measurement I demonstrate the inefficacy of this method for reverse detection of proxy servers in the IP list of past attacks.
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Implementation of General Discussion Group
Novotný, Vladimír ; Rychnovský, Lukáš (referee) ; Lukáš, Roman (advisor)
This thesis follows discussion forum's problems. This thesis wants to find a new view on various discussions on the internet. There is also a will to fight against spam. For this purpose is built in analyze system for new contributions. The main object of this thesis is to create an universal internet discussion forum which meets all formal requirements.
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Security risks of social networks and their prevention
Nguyen, Sao Linh ; Koch, Miloš (referee) ; Sedlák, Petr (advisor)
This diploma thesis deals with the issue of security risks and threats of social networks. The work includes basic information about the most popular online social networks such as Facebook, Twitter and Instagram. The work analyzes the development and use of the above mentioned networks. In addition, there are the risks and dangers of communicating on social networks and recommendations for safe use.
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Antispam filters
František, Jiří ; Fojtová, Lucie (referee) ; Pust, Radim (advisor)
The thesis is involves the desing antispam solution for operating system GNU/Linux. At the first is going through theory of transport, receive mail message and problematic of spam. The content of thesis is realize mail server with mail transfer agent Postfix. Amavis was used as antispam solution, which make an interface between Postfix and content checkers. This was created by SpamAssassin and ClavAV. Main goal was created aplication for setting of antispam filters. The result is possibility of setting a creating filters with black and white lists. Messages in quarantine ca
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Recegnition of Repeating SMS Patterns
Kočalka, Jakub ; Češka, Milan (referee) ; Holík, Lukáš (advisor)
Vďaka pokroku v rozpoznávaní spamu v e-mailoch a zvyšovaní povedomia používateľov smerujú spameri k menej preskúmaným médiám. Jedným z nich je \emph{short messaging service} (SMS). Táto služba poskytuje užívateľom možnosť reagovať na správy v krátkom čase a v skoro ľubovolnom prostredí. Tieto vlastnosti sú atraktívne aj pre legitímne podniky, ktoré potrebujú svojim klinetom zasielať krátke hromadné správy. Aj keď sú tieto správy z pohladu koncového užívateľa vyžiadané, pre poskytovateľa služieb SMS môžu predstavovať stratu, pretože tieto podniky často zneužívajú neobmedzené SMS plány určené pre bežných zákazníkov, aby sa vyhli plateniu za pre nich určené, ale drahšie produkty. Je preto žiaduce vedieť rozpoznať nevyžiadané aj vyžiadané hromadné správy. Hromadné správy sa zvyčajne generujú zo šablóny. Cieľom tejto práce je navrhnúť zhlukovací algoritmus ktorý správy analyzuje ako sekvencie lexikálnych jednotiek (slov), a vyhodnotiť jeho efektivitu v porovnaní s \emph{locality sensitivity hashing} metódou ktorá správy analyzuje ako reťazce symbolov. Práca vyhodnocuje vhodnosť algoritmu Smith-Waterman pre túto úlohu. Práca popisuje, prečo je Smith-Waterman (a ďalšie lokálne zarovnávania) nevhodný, a ako je možné ho nahradiť algoritmom Needleman-Wunsch (globálnym zarovnávaním), aby sa dosiahli oveľa lepšie výsledky. Výsledný algoritmus dokáže uspokojivo zhlukovať skutočné správy do kampaní a funguje dobre aj v situáciách, kde \emph{locality sensitivity hashing} kampane fragmentuje.
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Artificial Immune Systems for Spam Detection
Hohn, Michal ; Sekanina, Lukáš (referee) ; Schwarz, Josef (advisor)
This work deals with creating a hybrid system based on the aggregation of artificial immune system with appropriate heuristics to make the most effective spam detection. This work describes the main principles of biological and artificial immune system and conventional techniques to detect spam including several classifiers. The developed system is tested using well known database corpuses and a comparison of the final experiments is made.
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Antispam protection of web pages
Orsák, David ; Míča, Ivan (referee) ; Kacálek, Jan (advisor)
This thesis deals with questions of spam especially for web pages. The work specifies the term spam, history of spam and that individual division according to way diffusion and type sight. Here is decrypted questions legislature for spam and assessment consequences for this issue. With problem of spam is closely linked the botnets, which are main sources of spam, in this thesis is decrypted how botnet work and witch botnets are the biggest in this time that mean botnet which delivered the most of spam per day. The main part this work is to defined and decrypted different ways of spam protecting websites. Here are given type of protection from basic protection for hardy form protection, name CAPTCHA. In the practical part of the thesis offers some variants CAPTCHA, which could be reused for antispam protection for web pages
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Email Communication Problematics
Tlusťák, Karel ; Pecho, Peter (referee) ; Malinka, Kamil (advisor)
This work describes actual problems regarding to email communication. It shows how emails technically work and on these bases describes today's possibilities of email authentication. Next to it, the paper focuses on the biggest problems connected to emails - spamming and phishing. As far as spam is concerned, this work is dealing with methods of detection and filtering spam. Phishing is demonstratively shown on virtual case of phish-attack and attention is paid to anti-phishing tools as well. Other key-part of this work is low view of email problematic. This part covers judgement and eventual punishment of spamming and phishing in accordance to Czech, European Union and other countries' legislation. The phishing, considered to be the most serious problem concerning to emails, is demonstrated by the virtual court case which shows how related organs works and what are the problems about it. Some precedential cases are discussed there as well. The last part of this work describes the implementation of simple program which uses database in the Phishtank server to analyse phishing emails.
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