Healthcare organizations are now exploring use cases around Blockchain. Blockchain’s attributes of being distributed, immutable, transparent, indelible etc. and the inclusion of Smart Contract (in Ethereum) has opened this technology wide for many enterprises to use. This blog attempts to help healthcare enterprises to visualize, conceptualize, and evaluate their use cases on Blockchain, and help establish a clear mapping between actors of use cases and blockchain terms.
Each of the technical concepts in Blockchain like private key, public key, address, contract, ether value and the notions of miner, mining and application node play important roles in various healthcare use cases based on scope.
Blockchain: Key Concepts
A Blockchain is a peer-to-peer distributed ledger of chain of transactions. We can think of a Blockchain ecosystem as a cluster of nodes of computers (preferably with powerful CPUs and GPUs). This network collaborates with each other to maintain data and the consistency of data. Each action in the Blockchain is treated as a transaction that gets appended to the previous list of transactions hence forming chain of transactions.
A. Why is it called Blockchain?
A block in Blockchain is the container of the transaction and the block may have multiple transactions up to the block size limit specified by the Blockchain network. These blocks are linked to each other by storing the hash of a prior block as the header of the current block, making it a long, unbroken chain of blocks and hence the term ‘Blockchain’.
B. What is a transaction?
A transaction includes the data that one party sends to other plus some additional attributes to make this transaction successful on network. A transaction can be transfer of patient’s unidentifiable data from entity A to entity B. The transactions are sent to a node in blockchain which is then distributed over the network by participants (i.e. computer nodes). Designated nodes in the network validate the transaction and help in distributing it to other nodes for data consistency and availability at every node in network.
C. Where is the data? How is data distributed over a network of nodes?
Since the data is distributed, it does not have a single point of failure. Distribution is done by all the nodes in the network. This removes the dependency on a broker or a middle-man entity to execute the tasks on a central data repository.
D. How is the integrity of a transaction (i.e. sent data) maintained and secured during a transfer?
Blockchain uses cryptographic features like Public and Private keys, Proof of Work (POW), digital signature, transaction hash to maintain integrity and security.
A sender always initiates a transaction using a combination of Public and Private keys. Keys may also be signed with a digital signature. All transactions must be validated before being added to the blockchain. A difficulty value set by the blockchain framework to find the desired hash of data helps in maintaining security of transaction.
Designated miner nodes in the network look for these hashing challenges and attempt to solve it. This process is termed mining. Any miner may come up with the solution and every other miner in the network validates and then adds the transaction into the blockchain. So, this consensus mechanism prevents fraudulent validation by any miner (a minimum of 51% of consensus is required to add any transaction to the Blockchain).
The correct hash matching the difficulty value (set by the Blockchain) is generated after strong computations performed by miners, resulting in consumption of power/resources and hence that is called as Proof of work (POW). Such computation results in generating a strong hash of transaction. Miners work competitively to generating this POW and maintaining data consistency and make/generate rewards for themselves. These rewards are in the form of cryptocurrency (Ether - in case of Ethereum)
This is the basis of functioning of Blockchain. The data stored in blockchain is distributed over nodes which is backed by strong cryptography and hashed through POW.
How do Blockchain Concepts Apply to Healthcare?
As explained earlier, a transaction includes the data that is sent between the parties. For example, data exchange between a patient and provider or among different stakeholders can be considered a transaction. Public key of the participant is included as an additional attribute in the transaction.
B. Cryptographically Secured Public and Private Keys
These keys in a transaction correlate to the global identity of the actor on that Blockchain. Actors must also keep a passphrase to avoid data tampering. Global identity can be shared with other stakeholders in the system, so they can either read or write the data, given that there is no access constraint imposed by the owner.
C. Public Key Generation
There are two concepts in blockchain that can be interrelated to pubic key / global identity of actor.
- Account Address - This is required for any transaction on Blockchain. The account address is protected by a passphrase (private key) which guarantees that only the owner can perform critical operations and manage their data. The choice of having the account address as a global identity can vary, based on role of actor in use case.
E.g. A payer in a claim processing use case: We assume that the payer only operates on claims and there is no need to capture metadata of the payer on Blockchain. In such a case, payer can be assigned account address as a global identity which is used to make transactions and add records.
- Contract Address - In Ethereum Blockchain, the smart contract has opened the door to many enterprise use cases. Smart contracts can include code that is executed on the Blockchain with logical conditions. From the healthcare perspective, any actor can be put in a smart contract. Actors with a longer existence can have contracts in the Blockchain. Contract creation generates an identifier, termed as ‘contract address’, which can be used as global identity. Generally, the contract address is shared with other stakeholders for interactions.
E.g. A patient in a data sharing use case, with a substantial role in sharing, controlling and adding data, is assigned a contract address. Subsequent operations involving the patient are carried on their contract and the contract lives long in blockchain timeline. All authorized stakeholders can refer to the history of the patient by using the contract address.
D. Miners and Nodes
These concepts do not have a direct business context. They are part of the infrastructure / cluster to maintain data consistency and integrity.
Ether is a cryptocurrency that fuels Blockchain transactions and used as a reward to miners. It does not have a direct relationship to healthcare use cases, but some use cases can be built around it. For example, gamification use cases in healthcare, such as rewarding a patient who adheres to care guidelines.
When we think about healthcare use cases for Blockchain, the following points must be considered.
- Need for a single version of truth. One of the characteristics of blockchain is being transparent and immutable. Any data that goes in, is always appended and remains as history with the timestamp. This helps multiple parties in a healthcare use case to collaborate with the single consistent view of a data and do the research and again imprint their finding so same can be corrected and analyzed publicly.
- Avoiding use cases that uses Blockchain as a data repository and solution to scaling problems Blockchain can do more than this.
- Are there many participants involved with a need for consensus? A single participant and a well-defined task may not be a good use case for Blockchain, since such scenarios do not need consensus. Ideally, Blockchain use cases must include multiple parties that benefit from the Blockchain’s various attributes like data consistency, single version of truth, transparency etc. The parties then can be allowed or restricted access to the data on the Blockchain through its built-in security model.
As we understand the concepts of Blockchain and its applicability in solving real healthcare problems, use cases become clearer. We must use this technology only after thorough analysis of the problem’s scope and evaluating the added benefit of using Blockchain.