[tor-talk] Tor entry and exit nodes

[moosehadley at gmail.com]

> On May 15, 2016, at 6:39 AM, katerimmel at sigaint.org wrote:
> 
> If an adversary (government) have in their hands some exit nodes(ex:logs
> from a VPN) can identify the entry node and then the ip of the pc
> connected?

Tor uses three nodes between the user and the destination. Each node only knows the IP of the point before it and the point after it.

For example, the entry node only knows the IP of the user and the middle node. The middle node only knows the IP of the entry node and the exit node. The exit node only knows the IP of the middle node and the destination.

An adversary would need control of all three nodes to be 100% certain of who the user is and what the final destination is.

If an adversary only controlled the exit or the entry node, they could make an educated guess by watching the amount of traffic leaving the user and arriving at the destination; but it would be impossible (or extremely difficult) to do this without extensive preparations beforehand.