Abstract: Cloud computing is a capable, evolving Internet computing of this era. It presents the users with a secure storage for storing the documents online wherein the users can take the benefit of freedom to access it remotely avoiding the usage of the data storage services. When it comes to cloud data security, new technique is required. Protecting data in the cloud can be similar to caring data within a traditional data center or enhanced data center like cloud. Authentication and uniqueness, access control, encryption, protected deletion, is a numerous authentication encryption term. For encryption-based data access control for cloud, in which it shows that the mechanism of security is dealing with revocation could achieve by the different security techniques. It demonstrates that a encryption method in cipher text updating key for authentication for trusted user, so a security susceptibility appears. A revoked user can still decrypt new cipher texts for that user want to request for the new secret keys to access data.

Keywords: Encryption, Trapdoor, Index, Searchable Encryption.