  In spite of previous widely held belief of the incompatibility of public key
cryptography (PKC) schemes for wireless sensor networks (WSNs), some recent
works have shown that, PKC based schemes could be implemented for such networks
in some ways. The major challenge of employing a PKC scheme in wireless sensor
network is posed by the limitations of resources of the tiny sensors.
Considering this feature of the sensors, in this paper, we propose an efficient
PKC based security architecture with relatively less resource requirements than
those of the other previously proposed PKC schemes for WSN. Our security
architecture comprises basically of two parts; a key handshaking scheme based
on simple linear operations and the derivation of decryption key by a receiver
node. Our architecture allows both base-station-to-node or node-to-base-station
secure communications, and node-to-node secure communications. Analysis and
simulation results show that, our proposed architecture ensures a good level of
security for communications in the network and could effectively be implemented
using the limited computation, memory and energy budgets of the current
generation sensor nodes.
