The advancement of semiconductor and ubiquitous technology resulted in a smart sensor networkingsystem, which is an application of wireless sensor networks to health care applications (WMSN).Wireless Medical Sensor Network (WMSN) is a real-time continuous patient monitoring system, which provides a cost-optimal wireless sensor networking platform to track patient’s physiological data through the sensors attached to patient body. Limited computational power, storage, communication and energy capacity of WMSN demands for energy efficient, light weight and high security mutual authentication schemes which provides unbreakable connectivity for end to end secure data delivery.
In 2014, He et al. proposed an authentication scheme for WMSN and claimed that their scheme is light weight and resists all major cryptographic attacks. However, in this paper we will show that He et al scheme is vulnerable to offline password guessing attack and other major ones. As a part of our contribution, we will propose an energy efficient, light weight and highly secure authentication scheme for WMSN which 56% more energy efficient compared to He et al scheme and 20.18% compared to Kumar et al scheme.