A DAG-enabled cryptographic framework for secure drug traceability with identity-bound authentication and anomaly detection

Counterfeit pharmaceuticals remain a major public health challenge, particularly in regions with limited regulatory enforcement and digital traceability systems. This study addresses that challenge by proposing a cryptographically anchored drug traceability framework built on a Directed Acyclic Graph (DAG) ledger for secure, decentralized, and verifiable supply-chain tracking. Unlike conventional blockchain architectures, the DAG structure supports parallel transaction validation, zero transaction fees, and low-latency edge operations, making it suitable for real-time pharmaceutical monitoring in constrained environments. Each drug transaction is represented as a DAG node containing a hashed content identifier (CID), digitally signed metadata, and parent linkages that preserve structural integrity and tamper resistance. Encrypted Near Field Communication (NFC) tags affixed to pharmaceutical packages interact with Aadhaar-linked identities to enable traceable, identity-bound authentication. In this work, NTAG424 DNA tags are employed for secure data exchange, with on-chip encryption and mutual authentication to minimize exposure of key material and mitigate man-in-the-middle attacks. To support offline or rural deployments, the framework integrates an edge-ledger buffering mechanism that ensures eventual DAG synchronization via Merkle-root anchoring. Anomaly risks-such as tag tampering, scan failure, and connectivity interruptions-are predicted using a hybrid deep learning model that combines Long Short-Term Memory (LSTM) and Convolutional Neural Network (CNN) layers trained on synthetic, simulation-generated datasets enriched with environmental and behavioral covariates. In a simulated evaluation encompassing 1,000 pharmaceutical units across five regions, the system achieved 94.5% anomaly detection precision, 0.92 traceability accuracy, and 85 ms median latency. All evaluations were performed in a controlled simulation environment using Docker Swarm-based distributed containers on Raspberry Pi 4B edge devices with IOTA Chrysalis nodes and Grafana analytics dashboards. All reported metrics are consistent with the performance summaries in Table 14 and Fig. 10. Overall, this research demonstrates the simulation-based feasibility of a DAG-NFC framework for secure and interoperable pharmaceutical traceability. The results suggest potential scalability and privacy preservation under controlled conditions, though full operational validation through real-world pilots and regulatory assessment remains an essential next step.