Nowadays there are many mobile applications which are in market. And some are used as the daily day needs like: Gas bill payment, Electricity bill payment, Mobile recharge, Movie tickets booking, Food delivery, Online shopping and last but not the least Fitness tracking. And people are giving more importance for the health. Hence there are plenty of application. Are these applications secure, because these health care applications will store all the user data in the server. So, if the application is not secured properly then the data which is been saved in the server may be hacked or manipulated. In this project AES algorithm is implementing to save the user details. If the AES algorithm is not used, then the data is manipulated, and the application will allow us to open any malicious website and the data of the user is been changed. And fitness application is implemented with and without the AES algorithm, so that there will be changes in the data with respect to security. A