Authenticated data redaction with fine-grained control

Redactable signatures, a branch of malleable homomorphic signatures for editing, have wide applications in online interactions, from privacy enhancing to bandwidth saving. Recent research tends to apply this technique to solve the issue of authenticated data redaction in electronic health records (EHRs) systems, social networks, smart grid, etc. However, most of existing schemes are vulnerable to unauthorized arbitrary redaction or additional redaction. Redaction control is a crucial mechanism to restrict the actions that legitimate users can perform in sensitive systems, as well as constrain unauthorized manipulations from any user. In this paper, we propose a novel and generalized approach for constructing redactable signature scheme with fine-grained redaction control (RSS-FGRC), which allows the signer to specify a flexible and expressive redaction control policy to regulate the redaction operation of redactors. We analyse the security, efficiency, and functionality of our new construction by comparing with other related works. The analysis results show that the performance of our construction has significant advantages over others, from the aspects of security and efficiency.