Deep Web.

What is the deep web?

The deep web is the part of the internet that search engines do not index. You cannot find its pages by typing a query into a search engine.

The US Government Accountability Office (GAO) says deep web content has not been indexed by traditional search engines. It names classified listings, forums and invite-only groups as examples of deep web sites.

How does the deep web work?

CISA, the US cyber defense agency, describes three layers. The surface web is indexed by search engines and needs no special software or credentials. The deep web is not indexed and requires special software or credentials to access. CISA gives an internal SharePoint site and a bank account portal as deep web examples.

The Europol and EMCDDA report on drugs and the darknet has a glossary entry that describes the deep web as a part of the internet not accessible to conventional search engines. It says the way in is to search within a particular website, and that government databases and libraries hold large amounts of deep web data. EMCDDA is the European Monitoring Centre for Drugs and Drug Addiction.

What is a simple example of deep web content?

This is a simple illustration only. A page that sits behind a login, such as an account portal, is not something a search engine can index. It belongs to the deep web even though the person who owns the account may use it with an ordinary browser.

How is the deep web different from the dark web?

The dark web is a smaller part of the deep web. The GAO calls it a small portion of the deep web that contains content intentionally concealed and that requires specific software to reach. CISA says the dark web requires the Tor Browser and may require extra credentials.

The Europol and EMCDDA glossary says the dark web, or darknet, is a network built on top of the internet that is purposefully hidden and designed for anonymity. Unlike the deep web, it is accessible only with special tools and software, beyond direct links or credentials. The same report says the darknet is part of the deep web.

The GAO adds that the dark web may be used for legitimate purposes, for example news organizations that let users send information anonymously. It also says some users may go there to conceal criminal or otherwise malicious activities.

Should you worry about the deep web?

The deep web itself is not a threat. It is a way of describing content that search engines do not list. Security teams tend to pay more attention to the dark web part, because it is hidden on purpose and some users go there to conceal criminal activity. Related terms are the dark web, threat intelligence and digital footprint.

Is the deep web the same as the dark web?

No. The deep web covers everything search engines do not index, including ordinary sites behind a login. The dark web is only a small portion of it and needs specific software to reach.

Is the deep web illegal?

No. The sources above describe ordinary examples such as an internal company site, a bank account portal, government databases and libraries. Being unindexed does not make content unlawful.

How big is the deep web?

The sources we opened do not give a reliable size, so we do not state one. Treat any exact figure you see with caution.