CertiMed: Identity-Aware Access Framework for Electronic Health Records

Electronic Health Records (EHRs) require sophisticated architectural frameworks to ensure secure data sharing while maintaining privacy, integrity, and availability across distributed healthcare networks. Existing approaches, including Attribute-Based Encryption (ABE) systems, Multi-Authority schemes, and blockchain-based solutions, suffer from architectural limitations including high computational overhead, centralized vulnerabilities, inadequate temporal access controls, and limited scalability for large healthcare deployments. This article presents CertiMed, a novel four-layer hierarchical architecture that integrates Identity-Based Encryption (IBE) with blockchain technology for scalable and secure EHR management. The architecture employs a systematic separation of concerns across blockchain consensus, IBE cryptographic operations, application services, and distributed storage layers. CertiMed introduces three key architectural innovations: (1) time-bound IBE delegation enabling automatic key expiration without re-encryption overhead, (2) decentralized Know Your Customer (KYC) verification through smart contracts eliminating single points of failure, and (3) immutable blockchain-based audit trails providing comprehensive compliance and traceability. Comprehensive evaluation demonstrates significant performance improvements over existing ABE-based systems, including 68-69\% reduction in encryption/decryption latency, linear scalability supporting 100,000+ concurrent users, and 99.8\% cost reduction through Layer 2 blockchain deployment. Security analysis validates robust resistance against network attacks (0\% MITM success rate), side-channel attacks ($<5\%$ success rate), and comprehensive compliance with healthcare regulations. The modular architecture enables cost-effective deployment with transaction costs below \$0.002 while maintaining enterprise-grade security guarantees suitable for large-scale healthcare networks.