TL;DR: The Dark Web is a collection of hundreds of thousands of websites that use anonymity tools like Tor and I2P to hide their IP address. While it’s most famously been used for black market drug sales and even child pornography, the Dark Web also enables anonymous whistleblowing and protects users from surveillance and censorship.
What is the Dark Web
The dark web is part of the internet that isn’t visible to search engines and requires the use of an anonymizing browser called Tor to be accessed. Search engines like Google, Bing, and Yahoo are able to search and index websites because of links. They use links to rank search results according to things like relevancy, inbound links, and keywords. Regular browsers search the so-called “surface web,” but that’s where the search stops.
The majority of Dark Web sites use the anonymity software Tor, though a smaller number also use a similar tool called I2P. Both of those systems encrypt web traffic in layers and bounce it through randomly-chosen computers around the world, each of which removes a single layer of encryption before passing the data on to its next hop in the network. In theory, that prevents any spy—even one who controls one of those computers in the encrypted chain—from matching the traffic’s origin with its destination.
About Tor
The Tor Project, Inc, became a nonprofit in 2006, but the idea of “onion routing” began in the mid-1990s. The Tor network is a group of volunteer-operated servers that allows people to improve their privacy and security on the Internet. Tor’s users employ this network by connecting through a series of virtual tunnels rather than making a direct connection, thus allowing both organizations and individuals to share information over public networks without compromising their privacy. Along the same line, Tor is an effective censorship circumvention tool, allowing its users to reach otherwise blocked destinations or content. Tor can also be used as a building block for software developers to create new communication tools with built-in privacy features.
Not to be mistaken with the Deep Web
When news sites mistakenly describe the Dark Web as accounting for 90% of the Internet, they’re confusing it with the so-called Deep Web, the collection of all sites on the web that aren’t reachable by a search engine. Those unindexed sites do include the Dark Web, but they also include much more mundane content like registration-required web forums and dynamically-created pages like your Gmail account—hardly the scandalous stuff 60 Minutes had in mind.
The actual Dark Web, by contrast, likely accounts for less than 1% of the web: Security researcher Nik Cubrilovic counted less than 10,000 Tor hidden services in a recent crawl of the Dark Web, compared with hundreds of millions of regular websites.
FYI there is a Tor meetup today (at the time of writing this) in Berlin.
References :