A Secure and Policy-Controlled Signature Scheme With Strong Expressiveness and Privacy-Preserving Policy

The policy-controlled signature (PCS) scheme uses the access policy to control signature verification permission. However public access policy that may contain private information will leak user privacy. At the same time, the expressiveness of access structures in the PCS schemes is weak. Therefore, we propose a policy-controlled signature scheme with strong expressiveness and privacy-preserving policy (PCS-PP), in which linear secret sharing schemes is to design access structure which has strong expression, the three primes composite order bilinear groups is used to hide the attribute value into the attribute name that may expose the privacy data by data distortion concept. The proposed PCS-PP scheme not only has correctness and privacy-preserving policy, but also supports fine-grained signature verification. In addition, the unforgeability is proved in the random oracle model. Compared to the related schemes, the proposed PCS-PP scheme has superiority in features, computation cost and storage.