Abstract: Secure sharing of medical data and privacy protection are crucial for improving healthcare service quality.To address critical challenges in current medical systems,including data silos,privacy breaches and auditing difficulties,a data security sharing and privacy protection scheme for medical consortium blockchain is proposed.Firstly,the scheme constructs a patient-ID-indexed “main-side” chain storage architecture,where the main chain stores personal information,while the side chain stores medical records and addition trajectories,enabling efficient data retrieval.Secondly,Traceable ring signature technology is introduced to preserve user anonymity while supporting identity traceability in the case of medical disputes,balancing privacy protection and regulatory needs.Furthermore,a threshold signature mechanism without a trusted center is adopted,leveraging distributed key generation and threshold signature technology to provide decentralized approval and verification for medical record additions,achieving access control and secure sharing.Finally,security analysis and experimental simulations demonstrate that the proposed scheme outperforms existing solutions in terms of computational and communication overhead,which demonstrates its practical feasibility and effectiveness.

Key words: Secure sharing, Privacy protection, Blockchain, Traceable ring signature, Threshold signature