Onion Routing

From Computing and Software Wiki

Onion Routing provides a way for two computers to communicate on a network anonymously. In order for this to work, a message is encrypted and placed inside an 'onion'. The intermediate nodes along the path, called onion routers, decrypt (peel off a layer) of the onion to reveal the next router along the path to receive the onion.

Contents 1 Onions 2 Anonymous Communication 3 Vulnerabilities 4 Tor 5 See Also 6 External Links 7 References

Onions

Onions are created by the sender of a message, who first determines the network path along which it wishes to send a message. Each onion router on the path has its own public key. The sender encrypts the message multiple times by the public keys of each of the intermediate routers. Starting with the public key of the last router on the path, and continually encrypting the message with the previous router's public key. The final message to be sent is encrypted with the public key of the first router in the path.

The concept of the onion data structure is based on the idea of 'peeling off' layers of the onion at each intermediate node to reveal information for that specific node. The first router on the path decrypts the onion with its private key, which reveals the address of the second router on the path, and finally sent to that address. The newly 'peeled off' onion can now be decrypted by router two with its private key. This process is continued until the final onion router is reached.

Anonymous Communication

Vulnerabilities

Tor

See Also

External Links

• Tor: Anonymity Online

References

1. Onion Routing for Anonymous Communications. http://ntrg.cs.tcd.ie/undergrad/4ba2.05/group10/index.html.

2. Onion Routing. http://www.onion-router.net/Summary.html.