Public Cloud Secure Group Sharing and Accessing in Cloud Computing

Cloud computing is an emerging computing paradigm in which resources of the computing infrastructure are provided as services over the Internet. Sharing data in a multi-owner manner while preserving data and identity privacy from an untrusted cloud is still a challenging issue, due to the frequent change of the membership. To preserve data privacy, a basic solution is to encrypt data files, and then upload the encrypted data into the cloud. In this paper we are further extending the basic MONA by adding the reliability as well as improving the scalability by increasing the number of group managers dynamically. This paper proposes how user can access data after the time out. The storage overhead and encryption computation cost of our scheme are independent with the number of revoked users.