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Sourced from federal agencies. Fonteum, Inc., Delaware C-corp. © 2026.

Fonteum is a US healthcare provenance registry.

About Fonteum ›

Fonteum is a US healthcare provenance registry that publishes signed, chain-of-custody-attested research and data pages on Medicare, Medicaid, and federal regulator datasets, drawing from 22 federal source families across CMS, OIG, HRSA, AHRQ, and HHS.

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1,322,867 nurse-staffing records · CMS PBJ

Trust → Integrity → Chain

Attestation chain head.

Every snapshot Fonteum publishes is SHA-256 hashed at write time and appended to a Certificate-Transparency-style log. The head of that log — the most recent attestation — is published below. Once the per-snapshot previous_link_hash backfill lands under §sprint3-attestation-chain, every row will additionally chain backwards to the prior row, making any tampering detectable by a single recomputation.

Current head
snapshot_id
67
source_id
cms-hcris-hospital-2552-10
snapshot_date
2026-06-03
content_hash (SHA-256)
ac7b01a8e156d67c1f79a944026ac1a62b5e698488ea57486a5772b521c0860b
attested_at
2026-06-03T07:45:42.677105+00:00
previous_link_hash
(deferred — §sprint3-attestation-chain)
signing_key
(STH signing key publishes with first signed tree head)

Total attestations on file: 42

Witness co-signatures — snapshot 67

No witness signatures on file for this snapshot.

Verify this snapshot programmatically: /api/attestation/verify/67

How the chain works

  1. Each upstream archive is downloaded, SHA-256 hashed, and written to snapshot_attestations with the source archive URL preserved verbatim.
  2. Each new row carries a previous_link_hashfield set to the prior row's content_hash (or all-zero for the first row in a source family). Tampering with any historical row breaks every downstream link.
  3. A periodic STH (Signed Tree Head) seals the chain head with Fonteum's chain-signing public key. Verifiers fetch the STH, walk the chain backwards, and confirm every link.
/verify — re-hash any attested snapshot →/trust/integrity — full attestation index →/docs/cache — 90-day source mirror →

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