hostile node anonymity attack scenario

[Paul Forgey <paulf@xxxxxxxxxxxxx>]

What if a hostile _first_ node from your node were to pretend to honor 
your extend requests and complete the connection to the exit point, yet 
capture everything that happens? Such a node would be able to determine 
that it is the first hop from a particular connection because it would 
be able to see clear text data. I know the data between nodes is 
encrypted, but if you are the first node then you have knowledge of what 
the encrypted data is. While it pretends to honor extend requests and 
handshake new keys, it's actually doing so with itself so that it can 
see the entire circuit.

If I understand the design document, data isn't spread out across 
different nodes so that each node doesn't have the complete data. Doing 
so would strengthen tor against such an attack. Some scrambling 
mechanism so that each group of bytes need to be put back together with 
complimentary information routed through other nodes. This way, ALL the 
nodes from the node under attack would have to be under control by the 
same attacker.

Since intermediate tor nodes have key pairs signed with their ip 
information which prevent subverting connections to hostile nodes, I see 
that it would be extremely difficult to run one master hostile node and 
divert all traffic to it from a node (or ISP or country) being attacked.