An Efficient Two Factor User Authentication and Key Exchange Protocol for Telecare Medical Information System.

Telecare medical information system (TMIS) is substantially desir- able to patients by allowing them to remotely access medical services. Authentication schemes for TMIS try to ensure secure and autho- rized access. Recently, some smart card-based password authentica- tion schemes have been proposed, but privacy is not duly addressed. In this paper, we propose a key agreement technique for a medical server environment to overcome the limitations of the existing schemes. In the proposed scheme, we suggest bringing together the advance of both the crypto and Information Retrieval (IR) community to enhance the health-care process between patients and doctors by supporting an ef- ficient communicating platform on the internet which overcomes some drawbacks in traditional health-care services. However, to keep pa- tient medical data confidential against untrusted patients, we apply cryptographic methods by disclosing the data decryption key only to authorized patients and doctors to retrieve medical files containing certain keywords. We show that the proposed scheme is secure in the random oracle model (ROM) under the Bilinear Diffie-Hellman Problem BDHP. [ABSTRACT FROM AUTHOR]