A Proxy Transitive Signature Scheme

Abstract

Motivated by the research of privacy protection in the graph-based big data system, we propose a new signature scheme. The properties of the constructed signature scheme are twofold. On one hand, it is consistent with the requests of the proxy signatures. Our method allows a signer to delegate his/her signing right to another user in such a way that the latter can validly sign messages on behalf of the former, and other parties (who are not designated as the proxy signer) cannot create a valid proxy signature. On the other hand, it satisfies the properties of transitive signatures. One of the fundamental but vital properties is composability, which means that given two signatures σ_ij and σ_jk on adjacent edges (i, j) and ( j,k) , anyone without knowing the signer’s secret key can easily derive the digital signature σ_ik of the edge (i,k) . This property allows the signer to authenticate a graph in a cost-saving manner. Actually, our proposed design meets all the features needed for proxy signatures and transitive signatures, and it is provably secure in the random oracle model.