Device registration

When a device attempts to joins a secure network, it must obtain a copy of the network key to successfully communicate.

You can send the network key in the clear, but in most situations it will be encrypted with a link key. If the link key is not preconfigured on both devices, the trust center must be told the link key the joining device will be using to join. We call this process "registration" and is the method by which a link key and serial number of the joining device is securely given to the trust center through the physical serial interface. Because the registration information is not provided over-the-air, this is considered out-of-band registration and provides the highest level of security since the credentials cannot be extracted through RF channels.

Registration is performed using a Register Joining Device - 0x24 frame and is issued to the trust center (either centralized or distributed). The registration frame is used to register a link key, register an install code derived link key, or remove a previously registered device.