Blockchain-based PKI infrastructure for efficient management of medical prescriptions

The secure management of electronic prescriptions is a critical challenge in modern healthcare, where medication errors, drug diversion, and fraudulent claims collectively cost billions of dollars annually. Centralized Public Key Infrastructure (PKI), the prevailing e-prescription framework, presents a single point of failure, obstructs interoperability between doctors and pharmacists, and provides no safeguard against prescription duplication. This paper introduces a decentralized cross-chain PKI architecture that integrates four complementary technologies: permissioned blockchains utilizing Practical Byzantine Fault Tolerance (PBFT) consensus, three functionally separated InterPlanetary File System (IPFS) nodes, a formally specified Lock & Mint cross-chain synchronization protocol deployed on a dedicated Ethereum relay chain, and entropy-verified secure QR codes. The proposed solution incorporates a five-state certificate lifecycle with cryptographic chaining and enforces a strict separation between the control plane and the storage plane. We formally prove three security properties of the Lock & Mint protocol: reentrancy freedom, replay idempotency, and atomic rollback. Experimental evaluation conducted on three EVM-compliant Ethereum chains across 200 attack attempts spanning four threat categories (reentrancy, certificate forgery, QR cloning, and QR replay) yields an overall detection rate of 89% at a measured precision of 1.00 (F1 = 0.942), with prescription issuance completing in 74.0 ms and consumption in 70.5 ms on average. These results indicate that the proposed framework achieves robust, formally analysed prescription management with performance margins that are compatible with clinical workflows.