  Recent emergence of electronic culture uplifts healthcare facilities to a new
era with the aid of wireless sensor network (WSN) technology. Due to the
sensitiveness of medical data, austere privacy and security are inevitable for
all parts of healthcare systems. However, the constantly evolving nature and
constrained resources of sensors in WSN inflict unavailability of a lucid line
of defense to ensure perfect security. In order to provide holistic security,
protections must be incorporated in every component of healthcare sensor
networks. This paper proposes an efficient security scheme for healthcare
applications of WSN which uses the notion of public key cryptosystem. Our
entire security scheme comprises basically of two parts; a key handshaking
scheme based on simple linear operations and the derivation of decryption key
by a receiver node for a particular sender in the network. Our architecture
allows both base station to node or node to base station secure communications,
and node-to-node secure communications. We consider both the issues of
stringent security and network performance to propose our security scheme.
