Sharif Digital Repository

The importance of confidentiality and anonymity maintaining mechanisms are not hidden to anybody these days. With the worldwide web spreading rapidly, protecting the users' data flowing through it has become one of the most critical challenges to anonymity mechanisms. Nonetheless, machine learning algorithms have shown that they can reveal some explanatory information, even from encrypted traffic. Website fingerprinting attacks are a group of traffic analysis attacks that aim to detect the website which the monitored user has already visited. The current research takes a brief survey over website fingerprinting attacks presented in recent studies plus the defenses which took devised against... 

Governments and organizations need to classify network trac using deep packet inspection systems, by protocols, applications, and user’s behavior, to monitor, control, and enforce law and governance to the online behavior of its citizens and human resources. The high capacity of machine learning in the classication problem has led trac monitoring systems to use machine learning.The development of machine learning-based trac monitoring systems in the eld of research has reached relative maturity and has reached the border of industrial, commercial and governmental use. In the latest trac classi-cation studies using neural networks, as the most ecient machine learning methods, the classication... 

Today, we live in an information age where all people can access the vast amount of data in the world by connecting to the Internet.Since the Internet has expanded significantly to share information, some individuals and organizations seek to be able to prevent the possible sabotage of some people by monitoring network users. Analysis of computer network traffic is one of the importance issues that many activities have been done in this area. One of the most important questions in traffic analysis is to identify the main content of traffic on the encrypted network. Numerous studies have shown that the traffic of websites visited through the Tor network, including Specific information that... 

Common privacy enhancing technologies fail to effectively hide the certain statistical aspects of encrypted traffic, namely individual packets length, packets direction and, packets timing. Recent researches have shown that using such traffic attributes, an adversary is able to extract various information from the encrypted traffic such as the visited website, used protocol or even spoken language. Such attacks in general are called traffic analysis attacks. Proposed countermeasure try to change the distribution of such features in users traffic but either they fail to effectively reduce the accuracy of that attacker or do so while enforcing a high degree of bandwidth overhead and timing... 

Website Fingerprinting is a trac analysis attack that allows an eavesdropper to determine the web activity of a client, even if the client is using privacy technologies such as Tor. Recent researches have shown that an attacker is able to detect which websites a user is visiting over than 98% accuracy, While previous countermeasures fail against this kind of attacks. In this research, we introduce two defenses. In the rst defense, we exploit deep neural network vulnerabilities by using Adversarial Example.In this method, we add small perturbation to trac which misleads classier to detect websites that the user has visited. In the second defense, we introduce a defense mechanism based on...