The Dark Web is a part of the World Wide Web, which cannot be found with conventional search engines like Google, Bing or Yahoo and requires special technology for access. In contrast to the Visible Web or Surface Web, the Dark Web is accessible only with special browsers such as the Tor network and so-called .onion links. Similar to Google and Co., hidden wikis provide links to the actual content that can be accessed with the Tor browser.
Access to the Dark Web is encrypted and anonymized by these technologies. The Dark Web is often associated with illegal content and business. Not all websites and marketplaces in the Dark Web are per se illegal – there are also whistleblowers and websites, which only link sources or forums that are active there. The term “Dark Web” should be distinguished from the Deep Web (also Invisible Web), since the Deep Web can be reached with normal browsers but is not indexed by search engines (for example, forums or databases).
The World Wide Web is much larger than the information and sites that are accessed by regular browsers and indexed by traditional search engines. According to a study by BrightPlanet, it is 500 times larger than the surface web or visible Internet, which is used daily by billions of people. However, the largest amounts of data on the WWW are topic-specific and not necessarily relevant when the size of the Dark Web is investigated.
This includes specialist databases, library catalogs, links, secret data from organizations such as NASA or the database of the National Climatic Data Center. Such information is not accessible to search engines such as Google, but cannot be considered a real Dark Web. The terms Visible Web, Deep Web, and Dark Web are often confused and misused in this context.
The information that can be found in worldwide networks by users and search engines is only a small part of what is considered to be the World Wide Web by experts. Estimates assume that search engines or URLs can only reach 1 to 5 percent of all information. As a result, the Deep Web and the Dark Web would be much larger than the Internet we use every day.
In general, the Dark Web consists of Darknet websites, marketplaces, services and forums whose access is governed by the peer-to-peer principle. Anyone wishing to access it is required to know either an insider or a specific technology. In particular, the use of technology is associated with hurdles for regular users because these so-called overlay networks work with sophisticated encryption technologies and anonymization methods.
Two properties are characteristic of the Dark Web. On the one hand, the onion routing and on the other, the Tor network and similar networks, which represent an implementation of the onion principle.
Onion routing is an anonymization technique used in the Dark Web. If a user requests a website, the content is sent to the user via separate and constantly changing routes. On these routes, there are so-called mixes, which basically represent the stations that pass through the information. Thus, content is not forwarded from a sender to a recipient, as is the case with HTTP communication, but via several transmitters and receivers that operate as proxy servers and virtual networks (VPNs). A requested website is, so to speak, cut to pieces and reassembled by the user.
Depending on the direction of the communication, either the sender or the receiver (or both parties) is anonymized by means of these intermediate steps. The intermediate stations encrypt or decrypt information. They are also referred to as nodes in the network. Since the path of information can be graphically represented as an onion, this encryption and decryption method is called onion routing. In order to monitor the data traffic during onion routing, the observer would have to know all nodes, but these routes are usually changed at regular intervals.
As a rule, onion routing requires higher data transfer times, since the information must first be fragmented and then composited. Moreover, due to the often illegal activities, it is likely that certain areas of the Dark Webs are being monitored and tracked by investigating authorities if this is technically possible.
The Tor network is based on the idea of onion routing and adds some technical details. To create an anonymous connection between two communication users, one of them must first download and install a client that is described as an onion proxy. The onion proxy is a support program that connects to the Tor network. As a first step, the client downloads directory data which is digitally signed. The directories act as an authority listing all available Tor nodes on the network. The directory data is encrypted asymmetrically so that the client gets real data.
In a second step, the onion proxy selects a route through the Tor network. The nodes that are supposed to pass information are randomly selected. The route is changed after about ten minutes, so that another element is added to the obfuscation. The onion proxy now exchanges data with the first Tor server via the transmission and establishes an encrypted connection. If this connection is established, another Tor server is added and an encrypted connection is generated again. This connection is usually carried out with up to three nodes until information is transmitted between the client and the server in the network.
A “random stumbling” over Darknet websites is legally not a problem. However, as soon as content is viewed which falls under critical legal areas, caution is advised. Some such marketplaces and forums deal with drugs, weapons, child pornography, credit card fraud, and many other illegal products and services. Establishing a business relationship with a provider in the Dark Web may be punishable under the law. In such cases, attorneys recommend bringing a criminal complaint to the police. This is also possible anonymously.
In Germany, the existence of the "Dark Web" was unknown to many people until the tragic incident "Amoklauf" of David S. in Munich in the summer of 2016. The amok runner had bought his weapon over the dark web, which was discovered by investigators after the crime. In public discussion, the topic of the dark web became more present and known.
The Dark Web remains inaccessible to search engines like Google or Bing due to the technologies used. The content cannot be indexed by them and, in most cases, this is not desirable as they violate the guidelines of the search engines.
With regard to online marketing, no serious website should go near Darknet websites and link them via onion links or refer to it in any way. Similar to pornographic content in the traditional Internet, it is to be feared that search engines view such activities as bad neighborhood and downgrade the linking site in the ranking.