onion routing
n.— «Tor works through a technique called onion routing, which uses numerous routers through which communications will pass. As data passes through points on the Tor Network, each point knows only where the data is going and where it came from. As the network grows, it becomes increasingly difficult to trace a connection’s origin.» —“Anonymous Web Surfing Made Easy” by Jim Rapoza eWeek Oct. 9, 2006. (source: Double-Tongued Dictionary)