Cloud computing is a collection of technologies that have come together with the use of internet it will serve the customer's or user's. While user's store their data in the cloud it is important that the data should be in a secure manner. For maintaining the data securely, the authors have proposed a scheme which consists of three entities those are users, TPA and the cloud server. Here, in the place of cloud server they have used dropbox. In this paper, they will be able to provide security for the data which is stored in the cloud server from the unauthorized access.