Abstract: The Benefited from Cloud Computing, clients can achieve a flourishing and moderate methodology for information sharing among gathering individuals in the cloud with the characters of low upkeep and little administration cost. Then, security certifications to the sharing information records will be given since they are outsourced. Horribly, due to the never-ending change of the enrolment, sharing information while giving protection saving is still a testing issue, particularly for an untrusted cloud because of the agreement attack. In addition, for existing plans, the security of key dispersion depends on the safe communication channel, then again, to have such channel is a solid feeling and is difficult for practice. In this paper, we propose a safe information sharing plan for element individuals. Firstly, we propose a safe route for key dispersion with no safe correspondence channels, and the clients can safely acquire their private keys from gathering administrator. Besides, the plan can accomplish fine-grained access control, any client in the gathering can utilize the source in the cloud and refused clients can't get to the cloud again after they are rejected. Thirdly, we can protect the plan from trickery attack, which implies that rejected clients can't get the first information record regardless of the possibility that they scheme with the untrusted cloud. In this methodology, by utilizing polynomial capacity, we can achieve a protected client denial plan. At long last, our plan can bring about fine productivity, which implies past clients need not to overhaul their private keys for the circumstance either another client joins in the gathering or a client is give up from the gathering.

Keywords: Access control, Privacy-preserving, Key distribution, Cloud computing.