A typical tor circuit has
Browser -> entryNode(A) -> relay(B) -> exitNode(C) -> Server
This is prone to timing related attacks if both entryNode and exitNode are controlled by the adversary. Let say a website has
/home.png, tor browser is going to use the same circuit for each resource and the sizes of responses help the adversary to de-anonomyse. I understand we cannot change the exit node as the servers may have tied the session with the ip address of the exit node but why can't we use different entry nodes and relays?
This way even if one of the entry node is controlled by the attacker, it makes it difficult to use it to perform a timing attack. So the circuits will look like
For index.html: Browser -> A1 -> B1 -> C -> Server For index.js: Browser -> A2 -> B2 -> C -> Server For home.png: Browser -> A3 -> B3 -> C -> Server
Are there any downsides to this approach?
The new set A1, A2, A3 forms the guard node.