Health data remains the most valuable asset in healthcare, which makes managing it securely and efficiently a vital sensitive issue. Its importance lies in the various critical info it combines, including medical records of patients, research outcomes, tracking info on drugs and products, and socioeconomic, environmental, and behavioral information relevant to health and wellness. However, current health systems lack interoperability and data standardization, which makes it hard to transfer data between companies and health providers due to different standards and software structures.
That’s why health organizations are trying to take an additional step to direct a patient’s standardized set of data to a nationwide blockchain transaction layer. Data stored on the blockchain will be universally available to individuals through the private-key mechanism, allowing patients to access their information and share it much more seamlessly with healthcare providers, pharma, or research centers.
Data types on a blockchain
As the blockchain is a transaction layer, it can store two types of data: On-chain and off-chain data. On-chain data is information stored directly and entirely on the blockchain network. On the other hand, off-chain data includes links stored on the blockchain that point to large data sets in a separate database.
All records on a blockchain are available to the public to check and verify their integrity, so how about large data sets or sensitive data? Storing confidential information or abstract data like x-ray images on the public blockchain is not safe and feasible. So we would need an off-chain repository to store large amounts of data and link them securely to the chain, keeping the blockchain for storing crucial business logic, data summaries, and pointers to the off-chain data.
On-chain vs. off-chain data
Storing medical data directly on the blockchain ensures that it is fully secured and accessible by permissioned individuals or entities. However, storing large data files challenges scalability and slows down block processing speeds. Fortunately, encrypted links are minimal in size and get activated when users with the correct private key access the intended block and follow the link to a separate location containing the data.
On-chain data includes standardized data fields that could contain summary information in text form (like age and gender), while off-chain data could be extensive medical details (like notes) or abstract data types (like MRI or x-ray images and human genome).
Pros and cons of each
The advantage of on-chain data is that it’s immediately visible to all connected entities and institutions, allowing blockchain to be the single source of truth. Its downside is that there are constraints in the size and type of data we can store directly on the network. Thus, organizations should consider how we store data by carefully evaluating confidentiality and technical constraints.
Alternately, the advantage of off-chain data is that it could be data of any size or format, and we would securely point to them by hashes and encryptions available on the blockchain network. The cons we should consider are that this data isn’t instantly visible by the network, and each record requires access to each health institute’s system. It also requires micro-services and additional integration layers. Another downside would be the possibility of information decay on the blockchain.
The preferred solution
Blockchain technology in healthcare would be the most optimal solution when we know how to store health data. The preferred solution is to have a specific set of standardized data stored directly on the blockchain network for instantaneous, permissioned access, supplemented by links to off-chain data when necessary. The standardized data set could be demographic information such as birthdate and gender, medical histories like procedures and immunizations, or rendered services like conducted utilities and vital signs. Smart contracts are crucial in validating that entities submit correct data types or fields. Once the contract’s parameters verify that the submitted records meet predefined conditions, it will redirect the transaction to the blockchain for storage.
dHealth’s upgrade
To ensure decentralization at all levels, dHealth upgraded data storage, following the preferred solution of on-chain encrypted links that point to off-chain data. But instead of storing the off-chain data in a traditional database, it built a decentralized data repository. It’s developing a Self-Sovereign Storage for Health Data (3SHD), a scalable and open storage system operated by the dHealth community. 3SHD reduces the risk of compromised attacks as hacking a decentralized network infrastructure is far costlier and more challenging than hacking a single data silo. Remember to follow up with dHealth so you can know more about this decentralized storage and how it can be efficient for building dApps on dHealth’s infrastructure, along with many more promising projects.
