  In this work we study the problem of misbehavior detection in wireless
networks. A commonly adopted approach is to utilize the broadcasting nature of
the wireless medium and have nodes monitor their neighborhood. We call such
nodes the Watchdogs. In this paper, we first show that even if a watchdog can
overhear all packet transmissions of a flow, any linear operation of the
overheard packets can not eliminate miss-detection and is inefficient in terms
of bandwidth. We propose a light-weigh misbehavior detection scheme which
integrates the idea of watchdogs and error detection coding. We show that even
if the watchdog can only observe a fraction of packets, by choosing the encoder
properly, an attacker will be detected with high probability while achieving
throughput arbitrarily close to optimal. Such properties reduce the incentive
for the attacker to attack.
