Healthcare Blockchain System

A blockchain is a distributed, public ledger, recording transaction and tracking assets, and of which immutability is guaranteed by a peer-to-peer network of computers, not by any centralized authority. Assets can be tangible, such as homes or cash, or they can be intangible, such as patents or copyrights.

A blockchain consists of ordered records arranged in a block structure. Each data block contains a hash (digital fingerprint or unique identifier), timestamped batches of recent transactions, and a hash of the previous block. With this design, each block is connected in chronological order and the connected blocks are called a blockchain. It is practically impossible to modify one of the blocks in the middle of the chain because all of the blocks after the modified block must be modified at the same time. With this mechanism, the data on the blockchain network are immutable.

Medical data should be possessed, operated, and allowed to be utilized by data subjects other than hospitals. This is a key concept of patient-centered interoperability that differs from conventional institution-driven interoperability.

Blockchain technology can facilitate the transition from institution-driven interoperability to patient-centered interoperability.. Blockchain technology allows patients to assign access rules for their medical data, for example, permitting specific researchers to access parts of their data for a fixed period of time. With blockchain technology, patients can connect to other hospitals and collect their medical data automatically. There are many challenges arising from patient-centered interoperability, such as data standards, security and privacy, in addition to technology-related issues, such as scalability and speed, incentives, and governance.

In addition, these functions, which can be implemented with blockchain technology, may be useful for ensuring the rights of data subjects as defined by the EU General Data Protection Regulation. Because of the typical size and sensitivity of medical data, it is generally believed that the tag information of medical data, not medical data itself, will be stored in data blocks. However, some important information, such as information on drug allergies, can be published in a public blockchain.