Why This Glossary Exists
This glossary collects core terms related to the dark web. It presents definitions in plain language while noting data limitations where relevant.
Access and Navigation
Dark web — The portion of the internet that requires specialized software to access and is not indexed by standard search engines. It operates on overlay networks that emphasize user anonymity.
Deep web — All internet content that search engines cannot index. Most of it consists of password-protected pages and databases rather than hidden criminal activity.
Onion routing — A technique that routes traffic through multiple relays to conceal the user’s location and identity. Each relay only knows the previous and next hop in the chain.
Tor — Free software that enables anonymous communication by directing internet traffic through a worldwide volunteer network. It is the most common tool used to reach dark web sites.
Tor Browser — A modified web browser designed to route all traffic through the Tor network automatically. It includes built-in defenses against common tracking methods.
Sites and Services
Hidden service — A website or service hosted within the Tor network that is only accessible via an .onion address. These services keep both the server location and visitor identities hidden.
Marketplace — An online platform on the dark web where users buy and sell goods or services. Transactions often rely on cryptocurrency and escrow systems.
Mirror site — An alternative version of a dark web site hosted at a different .onion address. Operators create mirrors to maintain availability when primary addresses are blocked or taken down.
Security and Privacy
Exit node — The final relay in a Tor circuit that sends traffic to its destination on the regular internet. This node can see unencrypted traffic, which creates a known privacy risk.
Mixnet — A network that mixes messages from multiple users to obscure the connection between sender and receiver. It provides stronger anonymity guarantees than onion routing in certain scenarios.
Relay — A volunteer-run server that forwards encrypted traffic within the Tor network. Relays form the backbone that makes anonymous routing possible.
Economy and Tools
Cryptocurrency — Digital money such as Bitcoin or Monero used for transactions on the dark web. Many users prefer privacy-focused coins that obscure transaction histories.
Escrow — A payment arrangement where a third party holds funds until both buyer and seller fulfill the agreed terms. Dark web marketplaces commonly use escrow to reduce fraud.
PGP — Encryption software that allows users to send and receive secure, verifiable messages. It remains a standard tool for private communication on the dark web.
VPN — A service that encrypts internet traffic and hides the user’s IP address from their internet service provider. Some combine a VPN with Tor for additional protection, though the order of use matters.
Zero-day exploit — A vulnerability unknown to the software vendor and therefore unpatched. Such exploits hold high value in certain dark web communities.