Experimental Evaluation of Multi-Authority Attribute-Based Signature Protocol for Secure Blockchain-Enabled Electronic Health Records Maintenance

The increased use of Electronic Health Record (EHR) systems has further increased the necessity of securing, auditing, and fine-grained access control that has the capability of safeguarding extremely sensitive medical data. Centralized authentication and single-authority ABS schemes are still vulnerable to authority attacks, performance bottlenecks, limited scalability and cannot be used in large interconnected healthcare networks. In order to address them, this paper presents a Multi-Authority Attribute-Based Signature (MA-ABS) protocol combined with a permissioned Quorum blockchain to secure EHR management. The framework diversifies the issuance of attributes among independent authorities enhancing resilience and uses CP-ABE encryption and audit trails anchored on blockchain to preserve confidentiality, integrity and traceability. Test scores have improved significantly with 29.2 % faster signature generation, 31 % faster verification, 58-61 ms blockchain latency and 93.5 % signature success rate at 10,000 users. The use of CP-ABE encryption and IPFS-based off-chain storage makes storage and retrieval processes constant, guaranteeing the tamper-proof data processing. In general, the MA-ABS system proves to have strong resistance to insider attacks and collusion as well as to the high-throughput and low-latency of clinical processes. These results confirm the practicability of decentralized cryptographic administration of huge-scale healthcare implementations and the future opportunities of blockchain-based signature models to develop next-generation EHR protection.