Minimum Replication of User Data Integrating Anti-Collusion Scheme in Cloud Groups

Abstract

Cloud computing with the characteristics of intrinsic data sharing and low maintenance, provides a better utilization of resources. In cloud computing, cloud service providers offer an abstraction of infinite storage space for clients to host data. However, security concerns become the main constraint as we now outsource the storage of data, which is possibly sensitive, to cloud providers. To preserve data privacy, a common approach is to encrypt data files before the clients upload the encrypted data into the cloud. Unfortunately, it is difficult to design a secure and efficient data sharing scheme, especially for dynamic groups in the cloud. In this proposed system, a secure way for key distribution without any secure communication channels is proposed, and the users can securely obtain their private keys from group manager. It achieves fine-grained access control, any user in the group can use the source in the cloud and revoked users cannot access the cloud again after they are revoked. It also protects the scheme from collusion attack, which means that revoked users cannot get the original data file even if they conspire with the untrusted cloud.