Abstract: The majority of existing solutions are observed to still retain an authorization authority on the blockchain, which is viewed as exacerbating the “blockchain trilemma” issue. To address this, a zero- knowledge proof mechanism has been introduced in order to break away from the traditional model where key management and distribution are conducted by a central authority or trusted third party. Initially, a re-encryption protocol is employed to enable secure management and distribution of the attribute-based encryption algorithm’s master key without the involvement of an authorization authority. The correctness of the off-chain computations in re-encryption is then verified by using zero-knowledge proofs. Finally, a transaction aggregation circuit for blockchain ciphertext access control is developed to enhance system scalability and reduce on-chain costs. Through theoretical analysis and simulation, it is demonstrated that, in comparison to the traditional key management and distribution model, secure and efficient data sharing and access control are achieved, and on-chain overhead is effectively reduced.

Key words: data sharing ,  access control ,  zero-knowledge proof ,  blockchain ,   attribute-based encryption