PKC Based Broadcast Authentication using Signature Amortization for WSNs

Public Key Cryptography (PKC) is widely used for broadcast authentication. Intensive use of PKC for broadcast authentication, however, is thought to be expensive to resource constrained sensor nodes. In this paper, we propose a novel PKC based broadcast authentication scheme using signature amortization for Wireless Sensor Networks (WSNs). The proposed scheme exploits only one Elliptic Curve Digital Signature Algorithm (ECDSA) signature to authenticate all broadcast messages. Thus, the overhead for the signature is amortized over all broadcast messages. Besides low overhead, the proposed scheme retains high security that is as strong as conventional PKC based broadcast authentication schemes. Moreover, the proposed scheme can achieve immediate authentication and does not require time synchronization. For the implementation of the proposed scheme, an efficient public key distribution protocol is also presented in this paper. Experimental results of a testbed show that the overhead for authenticating a broadcast message is reduced significantly.