Abstract: In Cloud Computing, the feature of multi-tenancy gives privacy, security and access control challenges, because of sharing of physical resources among un-trusted tenants so, a suitable encryption technique with key management should be applied before outsourcing the data. In this paper we develop the methodology of policy based file access using attribute based encryption with cipher text scheme to secure the storage and sharing the cloud data with the cloud user. In this we also discuss the policy of revocation for file assured deletion so that no one can recover the deleted file from cloud and also discuss the policy for access to data storing centre so that the right user will access the right file in cloud.

Keywords: access control in cloud computing, attribute based encryption, policy based access control, revocation of file assured deletion.