Fig. 2

Depiction of blockchain data architecture components. This includes the core functions of blockchain data by generation of a first (genesis) block that is timestamped and may include certain transaction data/metadata (transation data) or state-of-data information. These blocks of data are chained together via a cryptographic hash of the data. The data layer represents where data can reside on the blockchain, primarily either storing data on the blockchain itself (on-chain storage) or storing the data in a different source but including a pointer or using a distributed application as an intermediary (off-chain storage). The core functions of the blockchain should also assess certain design considerations (in far right yellow box), including whether the blockchain is public, private or consortium, the consensus mechanism to be used, the type of permissions structure, where data should reside and how it should be managed, and the governance of the blockchain (who are the users, peers, validators, nodes, etc.). Finally, a feature layer including blockchain-enabled technology options, such as the use of cryptocurrencies/tokens, digital wallets, smart contracts, and distributed applications, can also be added if needed for a particular healthcare use case