onion routing

dark webprivacynetworking

A privacy technique that wraps traffic in layers of encryption and bounces it through several relays.

Each relay peels one layer and learns only the next hop, so no single node knows both who you are and where you are going, the idea behind Tor. It is legitimate privacy technology used by journalists, activists, and ordinary people; the "dark web" is one use among many.

Onion routing hides who is talking to whom by wrapping a message in layers of encryption, one per relay in the path. Each relay peels its own layer, learns only the previous and next hop, and forwards. No single relay ever knows both the origin and the destination, which is the entire design goal.

The property this buys is unlinkability rather than secrecy of content. The first relay knows who you are but not where you are going; the last knows the destination but not who asked. That separation only holds while the relays are independent, which is why an adversary who can observe both ends of a circuit, or who runs enough relays, can correlate timing and volume to defeat it. Traffic analysis, not cryptanalysis, is the realistic attack.

The practical consequences are usually misunderstood. The exit relay sees whatever the destination sees, so unencrypted traffic leaving the network is readable by whoever runs that exit. Latency is a design consequence rather than a defect, since traffic takes a deliberately indirect path. And the technology itself is neutral: it is used by journalists, people under censorship, and criminals alike, which is why discussing it accurately matters more than discussing it approvingly or disapprovingly.

Also known as: onion-routing, Tor, the onion router

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