1- Suppose a peer-to-peer network is based on a small-world topology. Describe an attack that does a large amount of damage to the network's capability for a small amount of work on the attack. Your description should include 1) the attack, 2) the expected damage to the network, and 3) how the damage effects the network's capabilities.

2- Two peer-to-peer networks N1 and N2 are identical except that N1's network topology has power-law characteristics and N2's network topology does not. Describe a query or series of queries that would demonstrate the differences between the two networks. Your description should include 1) the queries, 2) the expected results from the queries, and 3) how the results obtained distinguish the two networks.

- 16 copies of a file are stored in a connected, unstructured peer-to-peer network of 1024 nodes with each node having at most one copy of the file. A random node in the network issues a breath-first query for the file. What is the expected value of the distance in hops between the file and the query node? Justify your answer.

4- The secure hash algorithm SHA-1 has been broken and is no longer considered reliable for use. Describe a potential consequence of continuing to use SHA-1 in a peer-to-peer network. You may answer in general terms (which is harder), or with reference to a specific peer-to-peer network (which is easier). Your answer should involve non-security uses of SHA-1 in the network. In addition to answering the problem, your description should show that you understand 1) in what way SHA-1 is broken and 2) how a peer-to-peer network uses SHA-1 in non-security mechanisms.

5- Do you think it would make sense to Chord-style finger tables to a classic (unstructured) Gnutella networks? Justify your answer. Your justification should show that you understand what finger tables do in Chord and how classic Gnutella works.