Biomedical field serves as the benefit for human society. But in today's reckless running world people are casual about their health. Cases of heart attacks and deaths due to lack of help are increasing rapidly. For this purpose A secure IOT based modern healthcare system is best solution. Individuals with the heart condition who have been advised by their doctor to join in a regular exercise program would benefit from using the heart monitor so that they can be aware of their heart rate and adjust the level of intensity of their exercise to maintain a safe heart rate. Person who have been advised to exercise for weight loss or for cure of hypertension will also benefit from this device as it is a effective means of measuring progress in achieving exercise goals. Healthy person who are interested in improving their cardiovascular condition can also use the heart monitor to guide their exercise program and increase the intensity of their exercise in a controlled fashion. Thus, person who exercises regularly can benefit from the heart monitor device. The parameters to be observed in human body are Heart pulse rate, Heart pulse rate, Blood pressure, Body temperature, Body position. Day by day the usage of IOT technologies brings convenience of doctors and patients, since they are applied to different medical areas .The body sensor network (BSN) technology is one of the basic technologies of IOT developments in healthcare system, where a patient can be monitored using a collection of tiny-powered and lightweight wireless sensor nodes by doctor. However, the development of this new technology in healthcare applications without considering security makes patient privacy vulnerable. In this project, we highlight the major security requirements in BSN-based modern healthcare system.