Abstract: Consider a distributed file storage system having several servers and storages in different locations deployed over the cloud. A file can be uploaded to the nearest server where an authorized user is located and other authorized users can download the file from the same location. When a user tries to access the file from a different location, the nearest server has to fetch the latest version of the file from the original server, save it in its local storage and allow the requested user to access that file. But the same file is now stored in more than one place and hence the consistency problem arises. In this paper, this issue is addressed and resolved by the use of authorization policies to protect data from unauthorized access and an auditing strategy that checks whether the file is consistent among all the servers and ensures that the user gets the latest version of the file. Third party auditor is used for this purpose. Apart from consistency, the system also provides an attribute based access control to provide better security with policy management system.
Keywords: Distributed file storage, cloud databases, authorization policies, consistency, third party auditing.