  We consider the problem of defending a hash table against a Byzantine
attacker that is trying to degrade the performance of query, insertion and
deletion operations. Our defense makes use of resource burning (RB) -- the the
verifiable expenditure of network resources -- where the issuer of a request
incurs some RB cost. Our algorithm, Depth Charge, charges RB costs for
operations based on the depth of the appropriate object in the list that the
object hashes to in the table. By appropriately setting the RB costs, our
algorithm mitigates the impact of an attacker on the hash table's performance.
In particular, in the presence of a significant attack, our algorithm incurs a
cost which is asymptotically less that the attacker's cost.
