The HIPAA Security Rule's Technical Safeguards, 45 CFR 164.312, bind covered entities and business associates. Paragraph (b), Audit Controls, requires them to implement hardware, software, and/or procedural mechanisms that record and examine activity in information systems that contain or use electronic protected health information. Paragraph (c)(2) requires electronic mechanisms to corroborate that electronic protected health information has not been altered or destroyed in an unauthorized manner.
Recording the activity is the first half. Corroborating that the record itself has not been altered is the second, and it is the harder one.
In practice the audit log and the integrity mechanism sit inside the covered entity's own EHR or clinical system. Their assurance rests on that system being trusted, and on the entity not altering the store beneath it. A reviewer, or the Office for Civil Rights after a breach, is left corroborating integrity with a mechanism the entity itself controls. That is exactly where operator-controlled integrity is weakest.
Each audit-trail entry is hash-chained, so every entry commits to the one before it, and the head of the chain is written as a leaf into a public transparency log at log.markovianprotocol.com, an append-only log outside the entity's control. Seven independent witnesses, including Geomys and Google's transparency.dev witnesses, cosign the log checkpoint hourly, and checkpoints are anchored to Bitcoin via OpenTimestamps. A reviewer recomputes the chain from the records, which needs nobody, then checks inclusion of the head in the witnessed log from public endpoints. Once the checkpoint is anchored to Bitcoin, the head is checkable against the Bitcoin blockchain itself, independent of Markovian too.
Edit any historical entry and the chain breaks, no longer matching the recorded head. This does not replace the entity's safeguards, it turns the integrity mechanism the rule requires into one a reviewer can check without trusting the entity's system.
The same audit-anchor mechanism applies to a HIPAA audit trail. Each entry records the action on a record, the time, and a link to the entry before it. The chain head is anchored to Bitcoin and verified by recomputation.
Markovian provides the tamper-evidence and verifiability layer on top of the audit trail the rule already requires. Access, encryption, capture, and retention stay the covered entity's, and it is not a HIPAA compliance solution or legal advice.