[chord] Dealing with bad nodes

[obn.chord]

Does anyone know of any strategies to prevent, identify, or work-around 
malicious nodes in the chord overlay?

A couple of examples ...

1. Imagine someone wanted to prevent others from accessing a key-value 
pair. They could create a node and have the id be set to hash(key). 
Then, when others query that key, the node would simply ignore the query 
or respond that the key doesn't exist.

2. This is similar to the one above. Imagine someone wanted to prevent 
others from accessing a key-value pair, but a node already existed with 
an id of hash(key). They could create a node and have the id be set to 
hash(key) - 1. Then, when others ask to be routed to that key, the node 
wouldn't respond with its successor.

3. Imagine someone wanted to cut out a portion of the nodes in the 
overlay. They could simply add a node and adjust its finger table to 
skip over a bunch of nodes.

I'm sure there are more scenarios, but I think these 3 are the most 
obvious ones I can think of.