Table 1: Function of messages and the time when they are sent.

Message type Time when message is sent Function CS (Cluster Separator) message At the beginning of step 1 Determines a cluster border CR (Cluster Response) message Upon receiving a CS message Request to join a cluster FCS (Final Cluster Separator) message At the beginning of the step 2 Merges a CS node into a cluster Solicitation message When a victim does not receive a FCS message from its CS node Acquire witnesses to prove its legitimacy Solicitation response message When a node receives a Solicitation message and holds any evidence Proves a victim’s legitimacy Attacker report message When a victim confirms misbehavior of a CS node Excludes a CS node from members