Cloud computing which is the collection of resources and can be accessed from anywhere, performs the task of the computing and storage capacity for a service to provide the flexibility for users. The providers manage the infrastructure and platforms on which the applications run by user. Many users place their data on cloud. All the while in the past few years, an endless of online file storage services has been established. Although many of these services provide key functionality such as uploading and retrieving files by a precise user, more on going to the side of advanced services it offer features such as shared folders, real-time collaboration, and minimization of data transfers or unlimited storage space. As data is placed publically we need to search ways to protect the data from unauthorized access, files are uploaded publically and we need to retrieve them securely with token ensuring possession proofs. In this work I have presented an effective and secure data retrieval mechanism with token ensuring possession proofs and multilevel security application for ensuring data integrity (prevention and detection) in cloud environment.
