An Attribute-Based Signature Scheme with Flexible Access Control on Lattice

Attribute-based signatures (ABS) is a powerful cryptographic solution that provides fine-grained access control while improving flexibility and usability. This innovative approach allows generating and verifying digital signatures without revealing private information about the signer, thus maintaining user anonymity. Traditional ABS schemes usually rely on simple threshold structures, which make it difficult to support complex access control policies, have limited flexibility, and the computational complexity of generating and verifying signatures can be high, especially when dealing with a large number of user attributes. We propose a novel ABS scheme that incorporates more flexible access control mechanisms to overcome these limitations. Our approach utilizes secret sharing techniques to construct an access tree where user attributes are efficiently mapped to the leaves of the tree. This design supports a variety of logical operations, including "AND", "OR", and "threshold" gate structures, which enable sophisticated access policies. In addition, our scheme builds on the small integer solution (SIS) problem to ensure robust anonymity and adaptive unforgeability of selected information. This is achieved by selecting access tree structures and attribute sets under the Randomized Oracle Model (ROM) that conform to the defined access structure. The proposed ABS scheme not only enhances the security and privacy of digital signatures, but also improves the efficiency, which is a valuable contribution to the field of cryptographic access control.