An Efficient Approach for Data Sharing in Cloud Computing Using Digital Signature

Cloud Computing is the delivery of Computing services over the Internet. The Cloud Data services stores Data in the cloud and shares across multiple users, who can easily modify the shared data as a group. To ensure the shared data integrity, users in the group need signatures on all data blocks .Due to Data modifications done by different users in the group, it is essential that the shared data blocks are to be signed by different users. Once a user is revoked from the group for security reasons, the existing user must be re-signed. This system proposes a public auditing procedure for the integrity of shared data which is performed by a third party auditor, with valuable user revocation. Instead of downloading and ReSigning the shared blocks by the existing user, we allow the cloud to Re-sign blocks by digital signature during user revocation. Also, our process supports batch auditing and maintain the data in the form of versions. Hence it improves the efficiency of user revocation, maintain the Data modifications history and the compatibility to retrieve the earlier versions. Also Cloud computing is completely about productivity, economy, and corporate agility. But there raises a question how we can commercially attain those benefits if their cloud management solution becomes inefficient, incomplete, and inflexible. Even though there are many aspects in cloud environment.