Onion routing, explained
Onion routing uses layers of encryption along a route so intermediaries do not each need the complete end-to-end path.
- The field
- Technical
- Reading time
- 1 minute
- In this entry
- Meaning · relevance · limits
The meaning
Onion routing uses layers of encryption along a route so intermediaries do not each need the complete end-to-end path.
Why it matters
It is part of Tor's privacy model. End-to-end application encryption and secure endpoints remain separate protections.
The boundary
Routing privacy does not prevent users from identifying themselves to the destination.
Different hops see different parts of a path
A Tor circuit distributes knowledge of a connection across relays rather than giving one ordinary intermediary the complete path. That design still leaves endpoint behaviour and traffic correlation relevant to the threat model. Onion services keep their service connection within Tor and therefore do not use a public-web exit in the same way.
- Separate the onion service’s application permissions from the routing layer.
- Avoid publishing identifying headers, content or operator contact details by accident.