parts of the internet that are encrypted (= use a secret code), that cannot be found using ordinary search engines, and that are sometimes used for criminal activity

The dark web can provide a haven for extremist groups to exchange ideas. 暗网可以为极端组织提供一个随意交流的安全场所。

Illegal drugs and weapons can be bought on the dark web. 非法毒品和武器可以在暗网上买到。