Cloud computing multi-tenancy feature, which provides privacy, security and access control challenges, because of sharing of physical resources among untrusted tenants. In order to achieve safe storage, policy based file access control, policy based file assured deletion and policy based renewal of a file stored in a cloud environment, a suitable encryption technique with key management should be applied before outsourcing the data. Cipher text-Policy Attribute-based Encryption (CP-ABE) is considered as one of the most suitable scheme for data access control in cloud storage. This scheme provides data owners more direct control on access policies. However, CP-ABE schemes to data access control for cloud storage systems are difficult because of the attribute revocation problem. So this paper produce investigation on competent and revocable data access control scheme for multi-authority cloud storage systems, where there are multiple authorities cooperate and each authority is able to issue attributes independently. Specifically, this paper surveys a revocable multi-authority CP-ABE scheme. The attribute revocation method can efficiently achieve both forward security and backward security.

A.Shekinah prema sunaina."Study on Competent and Revocable Data Access Control Scheme for Multi-Authority Cloud Storage Systems". International Journal of Computer Engineering In Research Trends (IJCERT) ,ISSN:2349-7084 ,Vol.2, Issue 05,pp.365-368, May- 2015, URL :https://ijcert.org/ems/ijcert_papers/V2I517.pdf,

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