\documentclass{article} \begin{document} \begin{abstract} Denial of Service (DoS) attacks are considered within the province of a shared channel model in which attack rates may be large but are bounded and client request rates vary within fixed bounds. In this setting it is shown that clients can adapt effectively to an attack by using bandwidth as a payment scheme with time-out windows to determine rates. The server will be able to process client requests with high probability while pruning out most of the attack by selective random sampling. The protocol introduced here called \textit{Adaptive Selective Verification (ASV)} is shown to use bandwidth efficiently while also requiring no server state or assumptions about network congestion. \end{abstract} \end{document}