In Pictures: Five ways to beat the Great Firewall ...
Onion routing. All traffic is encrypted in multiple layers of encryption to protect its content, then routed through a series of designated onion routers. Each one peels away a layer of encryption to unveil instructions for routing to the next hop until the message is sent to its destination via the final router at the core of the onion. Developed by the U.S. Navy, the best known example of onion routing is Tor (The Onion Router).
In Pictures: Five ways to beat the Great Firewall of China