Wireless without considering the security. Therefore, a paramount

     Wireless Sensor Networks are widely used
in medical fields which are referred to as wireless medical sensor networks
(WMSNs). The healthcare applications use medical sensors to sense the patient’s
physiological data and transmit them wirelessly across the public channels and
store in the back-end databases. They are considered as promising fields where
the patients can be monitored continuously in hospitals and also at home. The
physicians can monitor their patients remotely by accessing patients’ health
data through wireless medical sensor networks. The medical researchers can use
the healthcare application for their research purpose and perform statistical
analysis on patient physiological data. The patients’ data will be transmitted
to data server and stored in some back-end systems. The patients’ privacy
becomes vulnerable if the healthcare applications are deployed without
considering the security. Therefore, a paramount necessity for healthcare
application is security, particularly in the account of patient’s privacy.
Wireless medical sensor networks conclusively improve patients’ nature of care
without exasperating their solace. There exist a lot of potential security
threats to the patient’s sensitive health data during transmission from the medical
sensors to the physicians or medical researchers. Various security threats to
healthcare applications that affect patients’ data privacy are summarized.

          The Paillier cryptosystems are used
for providing assured security for patient data during transmission. This
cryptosystem has an added benefit in its homomorphic properties where by
providing only a set of plaintexts and the public key parameters, the product
of the plaintexts is achieved. On the decrypting side, the user can decrypt the
received data and obtain the sum of the plaintexts. Paillier cryptosystem can
be useful for those applications which need top of the line security and
summation of the set of plaintexts. The existing solutions can provide privacy
to the patients’ data by ensuring protection against outside attacks but fails
to provide protection against the inside attacks. Some of the existing
solutions don’t provide security at all and some solutions do provide security
for the data transmitted over channels. The proposed system provides a
practical approach to overcome this issue and also provides protection against
inside attacks. In the proposed system, even if the attacker is successful in
compromising two of the three data servers, the solution is still secure.