Block Chain

CDX uses data stamping to anchor certain transactions to the Hedera Hashgraph Layer 1 public ledger. These transactions include information that’s relevant to showing data authenticity and transaction verification, proof of ethical and compliant data sharing, patient consent for data sharing and other use cases.

Typically, when we data stamp to Hedera, we create a hash value for the associated private data (such as patient health input captured by our app) that lives within our secure backend data sources and record that hash value in real-time on the public ledger. That becomes our “public anchor”, proving the authenticity of the transaction. (We also include verifiable account information, cryptographic signature and other cryptographically verifiable metadata). Our users or enterprise clients can verify the authenticity or provenance of their transactions by doing a “Verify” action from our app, where we—in memory—compare the current hash of any data transaction or data element with the corresponding public anchor recorded on Hedera.

For high value transactions, such as tracking the chain of custody of patient consent for participation with our telehealth providers or for possible inclusion in clinical research, we create a Hedera NFT to represent the original (base) patient consent and every status change in that consent—so called “dynamic consent”—is represented through associated Hedera transactions that “roll up” to the NFT. In this case, depending on the compliance policies we are observing, we use the Hedera Token Service and a related native smart contract to create the NFT and appropriately verify and attach related consent changes.

All of our interaction with the public ledger (Hedera) is done through privacy-preserved methods where the source health data is not exposed publicly (and is managed within our HIPAA compliant infrastructure). Where we do expose metadata publicly—depending on the indexing utility or the potential for deengineering—we perform one-way SHA-256 saltification of data using random, one-time use secret keys.

We provide a real-time transaction explorer that graphically shows ongoing, contiguous auditing of all data stamped or blockchain ledger anchored transactions, including various filtering, querying and related analytics tools. Additionally, we use the concept of a “rolling hash” to compare the sequence of the hashes created by our data stamping APIs to further ensure that the sequence of hashes is not broken or manipulated, to ensure not only the individual integrity of the data stamped transactions but also their fair ordering.

There are many important reasons why we use Hedera Hashgraph as our underlying public Distributed Ledger Technology (DLT). These include:

• Economic Viability (stable pricing in $USD, most fees 1¢ or below, mirror nodes for free reads)
• Performance (3-5 seconds to finality with transaction fairness, 1000+ tps, ABFT optimal consensus algorithm)
• Rich Platform (open-source, native consensus & token services, fast smart contracts, 3rd party enablers)
• Most Sustainable Public DLT (Layer 1, very low energy consumption)
• Accountable Governance (Governance Council of top organizations managing network, compliance & treasury)