Efficient Implementation of Public Key Cryptosystems on MICAz and TelosB Motes

Even though symmetric-key scheme, which has been investigated extensively for sensor networks, can fulfill many security requirements, public-key cryptography is more flexible and simple rendering a clean interface for the security component. Against the popular belief that public key scheme is not practical for sensor networks, this technical report describes the RSA and ECC public-key cryptosystem implementation in the real world sensor devices. We detail the implementation of 1024-bit RSA and 160-bit ECC cryptosystems on MICAz sensor motes, the latest product of Crossbow in the MICA family. We evaluate the performance of our implementation by running the public key and the private key operations in RSA cryptosystem, and signature generation and verification in ECC cryptosystem. We have achieved the performance of 0.79 second for RSA public key operation and 1.3 seconds for ECC signature generation. For comparison, we show our new ECC implementation on TelosB motes with a signature time 1.60s and a verification time 3.30s. We also explain the reasons that TelosB mote can not perform better than MICAz even though it is equipped with a 16-bit CPU. We believe that the experiment results are encouraging, and RSA and ECC are getting closer to be practially implemented in the sensor motes in the real world.