Securing device rejoining for a mesh network of a wireless lighting control system is disclosed. A potential security weakness of a mesh network protocol is that a proprietary link key may be discovered by close, expert examination of a device, potentially facilitating the joining of a “rogue” device to the network. Requiring subsequent rejoins of any device that had previously joined the network to use a current randomly generated link key, rather than the proprietary link key, prevents rogue devices only having the proprietary link key from joining.