67. Onion routing

This technique is being used for anonymous communication over a computer network.
You can read more here.

"The encrypted data is transmitted through a series of network nodes called "onion routers," each of which "peels" away a single layer, revealing the data's next destination."

"To create and transmit an onion, the originator selects a set of nodes from a list provided by a "directory node"."

Tor (The Onion Router) is one of the famous implements of onion routing and their logo depicts an onion.