ABSTRACT The lack of unified medical health record systems necessitates the development of large‐scale electronic health record (EHR) systems. Blockchain‐based frameworks are efficient when it comes to processing massive sensitive data and reliable data‐sharing mechanisms. This paper presents a novel proof‐of‐trust (PoT) consensus algorithm for a blockchain‐based healthcare framework (Health Chain) to offer secure and trustworthy data sharing. The consensus mechanism is formulated with fine‐grained access control and different encryption techniques (post‐quantum verifiable random function (PQVRF) algorithm and walrus‐based sidechaining model). The distributed data storage from blockchain utilizes the consortium chain‐based Hyperledger framework integrated with the interplanetary file system. The paper presents a PQVRF algorithm that can withstand quantum attacks and modify the consensus algorithm based on random functions to result in rapid and reliable consensus. The access and writing delays for the consensus algorithm associated with different EHRs are controlled via the walrus‐based sidechaining algorithm. The proposed framework validates the EHRs and blocks with minimal computational time. The proposed consensus algorithm is designed based on different objectives. The first objective is to offer scalability to support millions of users. The second objective is to overcome collusions and adversary attacks by designing Byzantine and unfaithful fault tolerance. The third objective is to offer comprehensive control to the user over their health data to ensure that the user's access is maintained as per their preferences. When compared with the existing techniques such as PoTE, IB, HBZKP, and MrBlock, the proposed model offers an improvement of up to 35% in data access times, 42% in interoperability, and 2% in data breaches; as per the results, we can infer that the proposed model offers authorized access to the user data, improved data scalability, data integrity, and data privacy. Data security is achieved by storing encrypted hashes of the EHR while sharing and retrieving them among different end‐users in the healthcare network. Although the proposed framework adopts post‐quantum cryptographic primitives for consensus formation, trust evaluation, and leader election, SHA‐2 is retained exclusively for lightweight EHR data hashing and integrity verification. This design choice does not compromise post‐quantum security, as SHA‐2 remains resilient under known quantum attack models when used for hashing.
D et al. (2026) studied this question.