text: Since the beginning of the digital area, privacy and anonymity have been impacted drastically (both, positively and negatively), by the different technologies developed for communications purposes. The broad possibilities that the Internet offers since its conception, makes it a mandatory target for those entities that are aiming to know and control the different channels of communication and the information that flows through. In this paper, we address the current threats against privacy and anonymity on the Internet, together with the methods applied against them. In addition, we enumerate the publicly known entities behind those threats and their motivations. Finally, we analyze the state of the art concerning the protection of the privacy and anonymity on the Internet; introducing future lines of research.
  @cite_13: Anonymity technologies enable Internet users to maintain a level of privacy that prevents the collection of identifying information such as the IP address. Understanding the deployment of anonymity technologies on the Internet is important to analyze the current and future trends. In this paper, we provide a tutorial survey and a measurement study to understand the anonymity technology usage on the Internet from multiple perspectives and platforms. First, we review currently utilized anonymity technologies and assess their usage levels. For this, we cover deployed contemporary anonymity technologies including proxy servers, remailers, JAP, I2P, and Tor with the geo-location of deployed servers. Among these systems, proxy servers, Tor and I2P are actively used, while remailers and JAP have minimal usage. Then, we analyze application-level protocol usage and anonymity technology usage with different applications. For this, we preform a measurement study by collecting data from a Tor exit node, a P2P client, a large campus network, a departmental email server, and publicly available data on spam sources to assess the utilization of anonymizer technologies from various perspectives. Our results confirm previous findings regarding application usage and server geo-location distribution where certain countries utilize anonymity networks significantly more than others. Moreover, our application analysis reveals that Tor and proxy servers are used more than other anonymity techniques.
summary: As of today, there is still no single solution available that is complaint with the definitions of privacy and anonymity introduced in Section 1. Nowadays, every communication done through the Internet that aims to be private and anonymous requires the use of cryptography and hard-trace routing techniques. Proxies and TOR are among the most used anonymity technologies @cite_13 and public-key cryptography is the most popular method aiming for privacy. Nevertheless, it is still possible to perform different attacks over these techniques, leading always to some result that invalidate the required properties for privacy and anonymity mentioned in Section 1. We introduce some of the possible improvements that current lines of research are proposing in order to enforce better privacy and anonymity.