Forwardsecurity using ID-based Ring Authentication on data sharing in cloud

Abstract

Data sharing has never been easier with the advances of cloud computing, and an accurate analysis onthe shared data provides an array of benefits to both the society and individuals. Data sharing with a large number ofparticipants must take into account several issues, including efficiency, data integrity and privacy of data owner. Ringsignature is a promising candidate to construct an anonymous and authentic data sharing system. It allows a data ownerto anonymously authenticate his data which can be put into the cloud for storage or analysis purpose. Yet the costlycertificate verification in the traditional public key infrastructure (PKI) setting becomes a bottleneck for this solution tobe scalable. Identity-based (ID-based) ring signature, which eliminates the process of certificate verification, can beused instead. In this paper, we further enhance the security of ID-based ring signature by providing forward security: Ifa secret key of any user has been compromised, all previous generated signatures that include this user still remainvalid. This property is especially important to any large scale data sharing system, as itis impossible to ask all data owners to re-authenticate their data even if a secret key of one single user has beencompromised. We provide a concrete and efficient instantiation of our scheme, prove its security and provide animplementation to show its practicality.