((("onion routing", id="ix_10_onion_routing-asciidoc0", range="startofrange")))In this chapter we will describe the Lightning Network's onion routing mechanism. The invention of _onion routing_ precedes the Lightning Network by 25 years! Onion routing was invented by U.S. Navy researchers as a communications security protocol. Onion routing is most famously used by Tor, the onion-routed internet overlay that allows researchers, activists, intelligence agents, and everyone else to use the internet privately and anonymously.
In this chapter we are focusing on the "Source-based onion routing (SPHINX)" part of the Lightning protocol architecture, highlighted by a double outline in the center (routing layer) of <<LN_protocol_onion_highlight>>.
In this chapter we are focusing on the "Source-based onion routing (SPHINX)" part of the Lightning protocol architecture, highlighted by an outline in the center (routing layer) of <<LN_protocol_onion_highlight>>.