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Trust → Integrity → Chain

Attestation chain head.

This page reports the signed head of the snapshot-attestation chain currently recorded. Newer snapshot attestations can exist outside the chain until a signed link is appended; only the indexed link below is part of this chain.

Current head
link_index
1496
link_hash (SHA-256)
f950647f7eb14a864cda5d73460366f44eb5f2e876f74e139c146444779c9855
previous_link_hash
358e0a235ef7a17156f4595d1590de77f3ca6fee9011f3de5fae3cd05027fbb0
signed_at
2026-07-12T10:37:03.546+00:00
signing_key
fonteum-chain-2026-06-16
attestation_id
1566
snapshot_id
1583
source_id
un-sanctions
snapshot_date
2026-07-11
attestation_content_hash (SHA-256)
b01b487e5c9a8f4ffded8148b32b3b5bea788504c150311171118eda245f00d4
attested_at
2026-07-12T08:01:04.370499+00:00

Total signed chain links: 1497

Witness co-signatures — snapshot 1583

No witness signatures on file for this snapshot.

Snapshot witness records are separate from the Ed25519 signature stored on chain link 1496.

Verify this signed chain link: /api/v1/chain/verify?link_index=1496

Re-derive the linked snapshot: /api/attestation/verify/1583

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. An attestation becomes part of this chain only when a signed chain_links row identifies it. Attestations without that link remain outside the signed chain.
  3. Each link stores the prior link's content_hash as its prev_hash. chain_state publishes the exact indexed head; verifiers recompute its payload and check the Ed25519 signature against the published key.

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What’s on file, by the numbers

Platform snapshot · 2026-08-24

13.4Mproviders & companiesProviders, organizations, owners, and facilities on file
26.2Msource-linked factsSource-linked field facts in the dated platform snapshot
90sources with dataDistinct snapshot source IDs with at least one positive record count
70fresh sourcesDistinct source IDs whose latest positive-data snapshot falls within the preceding 45 days
111sources integratedActive registry rows; integration does not establish a load
13state Medicaid jurisdictionsDistinct states represented in the state-exclusions serving table

Integrated, with-data, and fresh-observation counts are separate. No platform-wide source-completeness count is published. Completeness is source-specific and must be evaluated against the named source's expected scope. State coverage is a separate jurisdiction measure.

Source authority is record-specific

Use the issuer named on the record.

Fonteum spans federal, state, and global public publishers. A source page or returned record identifies its issuer and dataset where that metadata is available. A platform registry count does not assign every page to one authority or establish loaded, fresh, or complete coverage.

Browse source records and their stated limitations →

Reproducible by design

Inspect the evidence each published figure actually supplies.

Source and date

Research pages expose the named public file and observation date where those fields are available. Source-file SHA-256 coverage is separate; facts do not currently link deterministically to signatures.

Available derivation

Studies with a retained release and committed derivation link the SQL or method used. Other studies state the evidence and reproduction limits they actually have.

Daily observations

Dated table row-count observations can detect local drift. They do not imply that an upstream publisher released or Fonteum ingested new data that day.

Named medical review

Reviewed by Jennifer Montecillo, MD, medical reviewer. Non-practicing medical reviewer.

Read the full provenance and attestation methodology →

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