The Deep Web & Dark Web

Surface web

The portion of the web that is indexed by standard search engines and freely accessible.

Deep web

Any web content NOT indexed by standard search engines — much larger than the surface web, and mostly mundane: online banking portals, private databases, academic journals behind logins, medical records.

Dark web

A small, deliberately hidden part of the deep web that requires special software to access and is often associated with anonymity — used both for legitimate privacy purposes and illegal activity.

Anonymous browsing tools:

• Onion router (e.g. Tor) — routes traffic through multiple encrypted layers/relays (like layers of an onion) so that no single point in the chain knows both who the user is and what they're accessing.
• VPN — encrypts a user's traffic and hides their real IP address from the sites they visit, providing privacy and location anonymity, though a VPN provider itself could technically see the traffic passing through it.

Advantages of the deep/dark web: privacy for legitimate purposes (whistleblowers, journalists, people in countries with censorship), access to specialised or private resources not meant for public indexing.

Disadvantages: can facilitate illegal marketplaces and activity, harder for law enforcement to monitor, can expose users to scams or malicious content with less accountability.