errors. At the same time, they have to protect the person’s confidentiality and keep the information secure. Achieving both is a balance of find form and function in design. In my previous post on Blockchain technology I shared thoughts on the potential and possibilities. Here is my perspective on a path and some specific thoughts on how blockchain can be used to make healthcare safer, more accessible and secure.
A blockchain is a set of records with many copies. Cryptographic signing guarantees the information’s integrity and authenticates each contributor’s identity. Cross-checking the copies prevents anyone from adding invalid data or deleting records. Only properly signed records get accepted into the system. Anyone trying to add a record needs to have the secret key. Anyone trying to remove records will create a copy of the blockchain that won’t match everyone else’s.
The best known blockchain application is Bitcoin, an online system of money and payments. People who don’t know each other can make payments without an intermediary like a financial institution. It’s only one of many ways blockchains can be used, though.
Health Records in Blockchain
Let’s consider a use case in healthcare. A provider would like to have access to as much information as possible about a patient’s medical and social history. The patient may have a relationship with multiple providers in multiple places across multiple states. A system for securely gathering all this information together needs to have these properties:
- The information needs to be available only to authorized parties and safe from nefarious activity or unauthorized views.
- Any authorized party should be able to add information.
- All entries should be authenticated by their source, so forgery is impossible.
- Unauthorized parties should NOT be able to alter or delete information.
Blockchain technology can provide all of these, but it requires a different approach from the commerce industry. For example, Bitcoin stores all of the information in the blockchain, but the information is purely abstract. It moves a quantity of bitcoins from one account to another. Everything on the blockchain is public, so it isn’t suitable for storing confidential information. Besides, storing everyone’s medical histories in a single document would present serious scaling problems.
Blockchain for Authorization
An approach which minimizes these problems is to use the blockchain only as a means of authorization, with the patient information securely stored elsewhere. The article “Blockchain For Health Data and Its Potential Use in Health IT and Health Care Related Research,” by Laure A. Linn and Martha B. Koo, describes how this could work.
For this purpose, the blockchain would be an index, not a database. Patients would be in control by designating who has permission to read and write information about them. Providers would be able to add data from a variety of sources, using open-source software and public APIs. Patients could set access permissions at a granular level. A patient receiving treatment for drug addiction, for example, might not want that information available to all healthcare providers.
Another use involves patients wearing devices to automatically update their records on a regular basis or when they have unusual readings.
Issues to Resolve
Preventing unauthorized access is vital, but the user is often the weakest link in online security. People aren’t good at remembering passwords that are hard to guess. Biometric authentication, such as an iris scan, could provide a better level of security for patients.
Some classes of users should have more access to data than others. A patient’s own caregiver should generally have unrestricted access, but a pharmacy needs only a limited set of data. Rules establishing access for user classes can be programmed into the system.
The data on the blockchain needs to be truly anonymous to the unauthorized viewer. Even if nothing is public but the patient’s identity, the timing of new entries in a person’s record could be a source of exploitable information. Patients should be identified only by keys that have no outside meaning. Even then, if a key’s association with a patient is discovered, it could be difficult to revoke or change. This concern needs further study. (On the other hand, Social Security numbers, which are overused and easy to discover, already pose a similar problem.)
For this approach to work, it has to be widely adopted. Competing implementations would fragment the available information. However, if everyone subscribes to the same blockchain implementation, it offers an inviting target to anyone looking to steal information. There have already been data breaches of traditional EHRs leaking information on millions of patients; defects in a universal system could allow the bulk theft of even larger numbers of records. The security level has to be extremely high.
It’s likely that rather than having one gigantic database for everyone, there will be competing databases used by different providers. A patient’s records might be scattered over several different databases. For the system to work well, they would need a high level of interoperability.
Any blockchain carries the risk that one party might take control of enough copies to outvote everyone else and falsify the data. A weighted voting system, with known trusted participants carrying extra weight when verifying copies, could help to prevent this.
The paper “Decentralizing Privacy: Using Blockchain to Protect Personal Data,” by Guy Zyskind, Oz Nathan and Alex Pentland, discusses the blockchain for authentication at a more technical level than Linn and Koo. It’s worth study by anyone working on an implementation.
Issues for the Future
The HIPAA security and privacy rules place strong requirements on handling of protected health information (PHI). The rules allow some flexibility in implementation, but the Office of Civil Rights, which administers HIPAA compliance, will need to make a judgment on whether a blockchain approach complies before healthcare providers are confident about it. Government agencies are already looking into the possibilities and challenges.
Blockchain technology for healthcare is in the early stages of exploration. We won’t see any full-scale deployment for years, but prototypes and limited implementations may be available before long. The approach could streamline the sharing of healthcare information, allowing fewer mistakes and better treatment for everyone.
Those are my updates to my previous post on Blockchain. I’m asked frequently if I see a path forward, and while I do, it will take a catalyst to rally a collabortive effort towards this approach. Seeing more cooperation by organizations such as Careqaulity and CommonWell Health Alliance work together can potentially be a catalyst to influence some type of standard to accelerate us toward a future which must happen if person-centric care is to be realized.