Abstract: One of the most important issues in Network is security. When data is distributed across networks or information is transferred via public networks, it is more prone to be attack by mischievous elements. In traditional security model, all the data stored in server and the users who use that data belong to the same security level. The security service provided by the storage provider is not enough. Since the data is stored anywhere across the network, the data owner has less control over the data stored in servers. Due to the issues in security, both owners and users are advised to verify the integrity of data with Provable Data Possession (PDP) before further usage of data. However earlier methods either unnecessarily expose the identity of a data owner to untrusted servers or introduce overhead on verification metadata for preserving anonymity. The proposed system is to build a security service through a trusted third Party .The system introduces a security mediator (SEM) which does not store any data at its end. The system is also able to generate verification metadata onoutsourced data for owners

Keywords: Blind Signature, Decryption, Encryption, Key Rotation algorithm, Metadata, Provable data possession, Security, Security Mediator, Server