Secure Data Sharing in Cloud Without Certificate Verification Process Using Id-Based Proxy Ring Signature

Data sharing has never been easier with the advances of cloud computing. Data sharing with a large number of participants must take into account several issues, including efficiency, data integrity and privacy of data owner. A ring signature is a simplified group signature without any manager. It protects the anonymity of a signer. Unlike the group signature schemes the ring signature scheme requires neither a group manager, nor a setup procedure, nor the action of non-signing members. This signature does not reveal the identity of the signer but it may be varied with this signature that the signer belong to the possible signers set. There is no revocation manager. This allows unconditional anonymity of signer. Therefore, we introduce proxy signature scheme to allow a proxy signer to sign on behalf of an original signer. Using this scheme, we can achieve the singer ambiguity and key secrecy. To achieve user account security, we employee authentication process. In this authentication process user thump impression is capture and compared with the user data which are stored in database during registration process.