Attribute-Based Online/Offline Signature Scheme Based on SM9

The attribute-based signature (ABS) scheme uses a set of attributes to identify users. The user can generate a valid signature only when the attributes satisfy the access policy. Compared with the traditional digital signature scheme, the ABS scheme not only utilizes a set of attributes to hide the real identity of users to obtain anonymity, but also realizes fine-grained access control by access policy. In ABS schemes based on elliptic curve, a large number of group exponentiation operations or pairing operations are usually required, which are computationally expensive, resulting in high computational overhead in the signature process. The online/offline signature technology can precompute expensive operations offline before knowing message, thereby reducing the online computing cost of lightweight devices. As a commercial cipher independently designed by China, the SM9 identity-based cryptographic algorithm has been standardized by ISO/IEC and is widely used. Based on the SM9 identity-based cryptographic algorithm, we propose an attribute-based online/offline signature (ABOOS) scheme based on the SM9 by using the online/offline signature technology in this paper. Not only ine-grained access control can be achieved, but also it is suitable for lightweight devices. In the random oracle model, the security of the proposed scheme is reduced to the qstrong Diffie-Hellman (q-SDH) hard problem. Theoretical analysis and experimental simulation show that the proposed scheme effectively reduces the computational cost of the signing process, and is suitable for application environments such as the internet of things. © 2023 Science Press. All rights reserved.