AES Data Encryption in a ZigBee Network: Software or Hardware?

This paper describes the experiments which have been conducted to determine the optimal implementation concept for AES (Advanced Encryption Standard) data encryption in a ZigBee network [1,2]. Two concepts have been considered. The first one is a AES128-CBC hardware co-processor embedded on a Spartan 3A FPGA. The second configuration implements the same cryptographic algorithm on the processor which controls the ZigBee nodes. The ZigBee modules in the network contain an 8-bit microcontroller which takes care of the ZigBee protocol stack –and the encryption calculations in the second case. Both approaches are examined and compared. In this paper we show that – in general– a software implementation is feasible in a ZigBee network, though a low-power hardware cryptographic co-processor could prove to be useful in some cases.