Smart Contract-Aided Attribute-Based Signature Algorithm with Non-Monotonic Access Structures

Attribute-Based Signature (ABS) is a powerful cryptographic primitive that enables fine-grained access control in distributed systems. However, its high computational cost makes it unsuitable for resource-constrained environments, and traditional monotonic access structures are inadequate for handling increasingly complex access policies. In this paper, we propose a novel smart contract-assisted ABS (SC-ABS) algorithm that supports non-monotonic access structures, aiming to reduce client computing overhead while providing more expressive and flexible access control. The SC-ABS scheme extends the monotonic access structure by introducing the concept of negative attributes, allowing for more complex and dynamic access policies. By utilizing smart contracts, the algorithm supports distributed trusted assisted computation, and the computation code is transparent and auditable. Importantly, this design allows information about user attributes to be deployed on smart contracts for computation, both reducing the risk of privacy abuse by semi-honest servers and preventing malicious users from attribute concealment to forge signatures. We prove that SC-ABS satisfies unforgeability and anonymity under a random oracle model, and test the scheme’s cost. Compared with existing schemes, this scheme has higher efficiency in client signature and authentication. This scheme reduces the computing burden of users, and the design of smart contracts improves the security of aided computing further, solves the problem of attribute concealment, and expresses a more flexible access structure. The solution enables permission control applications in resource-constrained distributed scenarios, such as the Internet of Things (IoT) and distributed version control systems, where data security and flexible access control are critical.