<p>Smart healthcare applications have received extensive attention thanks to their benefits to patients and medical organizations. These systems often rely on IoT devices combined with cloud computing to enable timely, continuous monitoring of health data. However, securing and ensuring privacy in healthcare IoT systems while maintaining performance standards is a significant research challenge. In this paper, we propose a novel IoT-based healthcare system (HIoT) that combines Blockchain technology to enhance the security and privacy of peer-to-peer IoT networks, and lattice-based cryptography to safeguard users’ privacy and data security against emerging threats posed by quantum computing. The proposed system relies on parallel and distributed processing for concurrent cryptographic operations, decentralized storage, and blockchain transaction validation across edge and consortium nodes. As the number of devices, users, and transactions increases, the system must meet the demands for scalability, concurrency, and low-latency processing. The proposed solution achieves computational and energy efficiency, making it easy to implement on resource-constrained devices. Additionally, our solution achieves robust data security, making doctors’ diagnoses or HIoT data deletion or tampering highly challenging and offers detailed permission settings to guarantee that only authorized entities can access and utilize the encrypted data.</p>