Abstract: Online data sharing systems and social networks provides security through the cryptographic solutions. For this, Cipher text Policy Attribute Based Encryption is mostly suitable for distributed data sharing systems since the data owner has full control to put in force access policies and updating the policies. Even if the CP-ABE has various advantages, it has a major drawback known as the Key Escrow problem. The Key Generation Center may perhaps decrypt any messages addressed to the specific users by generating their private keys. This is not appropriate for data sharing scenarios where the data owners would like to make their own private data only accessible to elected users key. So, this proposed System would help to fixed key escrow problem using a modified Escrow free Key generation Protocol. The improved Escrow free Key generation protocol ensures that neither the Key Generation Center nor the Data storing center can generate the secret keys individually. Instead the Key Generation Center and the Data storing center generate parts of secret key which are then integrated by the user. So as a result, the Escrow free Key issuing protocol will completely eliminates Key Escrow problem as well as the data owner would like to make their private data only accessible to designated users. Hence to overcome this problem fine-grained data access control provides a way of defining access policies based on different attributes of the users or the data object and the security is enhanced in order to send private keys by the data owner or the users .So the issue of key-escrow problem is resolved by issuing 2-pc protocols in system which will definitely protect the secure key escrow problem. As well as to improve the security Data integrity checking will be done. So as a result this Proposed System will help us to obtain more security and performance.
Keywords: Attribute Based Encryption (ABE), Cipher text Policy Attribute Based Encryption (CP-ABE), Data Integrity, Key Generation Center (KGC), Third Party Auditor (TPA).