Ensuring authenticity in Xbee Series 1

DigiJack

I have been working with Xbee for few days and intending to use Xbee (Series 1) +Arduino UNO as part of Wireless Sensor Network. I want the network to be secured, I can use the Xbee's AES capability to make the data transfer secure. But I want to make sure that the sender/receiver all are authentic. How can I be able to ensure that? I want to use AT mode.

What I am trying to say is, suppose there are few nodes (Xbee+Arduino) which collects data by sensor and there is one receiver. The receiver sends command to one of the sensor node (one to one communication) to collect sensor value from that node. My question is, how can that sensor node will be able to know that, the commander is authentic, not some adversary [that somehow knows the command format and sending the command pretending itself as commander]? Is there anyway to configure the Xbee so that it can respond to only authentic commander? There will be only one commander in the network, but is there anyway to set sensor xbee [as we can configure destination address] so that it will only respond to the authentic commander?

Chris Savage

Here is a FAQ from Digi on encryption. Please let us know if this answers your question.

http://www.digi.com/support/kbase/kbaseresultdetl?id=2214

Tracy Allen

Only if the intruder knows the encryption a key (ATKY xxxxxxxxxxxxxxxx) that has been preprogrammed into all of the network nodes.

If you decide to use API mode instead of AT mode, you can also have your µP firmware check the MAC address of the originating XBee. The MAC address would be rather hard to spoof.