A Proxy Transitive Signature Scheme

A Proxy Transitive Signature Scheme

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 σij and σjk on adjacent edges (i, j) and ( j,k) , anyone without knowing the signer’s secret key can easily derive the digital signature σjk 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.