Provably lightweight and secure IoHT scheme with post-quantum cryptography and fog computing: A comprehensive scheme for healthcare system.

Quantum computers threaten the security of commonly used public-key cryptosystems, such as Rivest-Shamir-Adleman (RSA) and Elliptic Curve Cryptography (ECC). This is because these quantum computers efficiently solve factorization and discrete logarithm problems, which are the basis for RSA and ECC. This compromises confidentiality, integrity, and authenticity in security systems deployed in various applications, such as Internet-of-Healthcare Things (IoHT). Post-quantum cryptography, while a potential solution, introduces computational overheads that can slow service delivery. This poses serious concerns in IoHT safety critical systems as it directly impacts patient safety and healthcare systems. This paper aims to design a post-quantum resistance scheme for IoHTs. Our scheme is based on ECC, Counter mode (CTR), and Key Encapsulation Mechanism (KEM). To guarantee the safety and storage of electronic records for the network entities and support scalability, blockchain and InterPlanetary File System (IPFS) were employed. To achieve improved levels of security and more effective control when accessing specific data and resources, we apply Role-Based Access Control (RBAC). In addition, we deploy Symmetric Searchable Encryption (SSE) for efficient and secure data search. The scheme's security was formally verified using the Scyther tool, and Burrows-Abadi-Needham (BAN) logic. In addition, informal security analysis shows that our proposed scheme offers mutual authentication, confidentiality, integrity, and other security requirements. In addition, it withstands well-known threats and some of the recent threats, such as phishing, quantum, and 51% attacks. Moreover, a comparative analysis was conducted with other related protocols to show the efficiency of the proposed scheme in the IoHT environment. The results indicate that the computation overhead was reduced by 90%, while communication cost and latency were relatively low. On the other hand, throughput was greatly increased while energy consumption was very low. The proposed scheme is a low complexity solution for IoHT environments to address existing threats and maintain data integrity. Blockchain and IPFS ensure secure, scalable e-record storage for network entities. Achieving secure, effective access control with RBAC and enhancing data searchability with SSE.