Key Agreement between two nodes of a Wireless Sensor Network Can there be a way to form a shared secret key between two nodes of a Wireless Sensor Network who are more than one hop away, simply on the basis of their IDs?
Yes, using identity-based cryptography; in particular the Sakai-Ohgishi-Kasahara non-interactive key distribution protocol, generalized in "Provably secure non-interactive key distribution based on pairing".

The downside is that it requires a "Private Key Generator", a trusted party which is able to compute the private key of any node. The private keys also need to be securely deployed in each node.

Using the protocol, each node will have and ID. They simply need to exchange IDs and will be able to compute a shared key.