A user anonymity preserving three-factor authentication scheme for telecare medicine information systems.

The telecare medicine information system enables the patients gain health monitoring at home and access medical services over internet or mobile networks. In recent years, the schemes based on cryptography have been proposed to address the security and privacy issues in the telecare medicine information systems. However, many schemes are insecure or they have low efficiency. Recently, Awasthi and Srivastava proposed a three-factor authentication scheme for telecare medicine information systems. In this paper, we show that their scheme is vulnerable to the reflection attacks. Furthermore, it fails to provide three-factor security and the user anonymity. We propose a new three-factor authentication scheme for the telecare medicine information systems. Detailed analysis demonstrates that the proposed scheme provides mutual authentication, server not knowing password and freedom of password, biometric update and three-factor security. Moreover, the new scheme provides the user anonymity. As compared with the previous three-factor authentication schemes, the proposed scheme is more secure and practical.