Hash Anchor Registry
Prove that a document or dataset existed in a certain state at a certain time — without a trusted third party.
The problem
/ 01Proving that a document or dataset existed in a given state at a given time is surprisingly hard without a trusted third party.
What it does
/ 03Anchors a content hash (e.g. SHA-256) to the registry with optional metadata.
Verifies a receipt by id or by hash.
Lists anchored receipts and exports the registry as JSON or CSV.
Private pilot adds
/ pilotPilot-ready: durable hash-anchor store available under NDA with a /v1 API for private pilots. The public studio card runs against /demo (ephemeral).
Who it’s for
/ 03- Teams proving document existence and state
- Compliance and legal functions issuing time-proofs
- Anyone needing verifiable, exportable receipts
In context
/ 01A foundation primitive — registry receipts can be sealed into image carriers with the Air-Gap Courier for offline verification.
Spec & limits
/ limits| Interface | Input limits | Output artifact | Failure mode | Non-claim |
|---|---|---|---|---|
Studio ephemeral /demo; pilot durable /v1 on your infrastructure. | TBD — verified in pilot acceptance | TBD — verified in pilot acceptance | TBD — verified in pilot acceptance | TBD — verified in pilot acceptance |
Related guide
/ guideSee the content hash anchoring guide for a deeper problem walkthrough and verification notes — evaluation notes for the live demo and for a private pilot. Also: try the live experiment and read the product overview.
Frequently asked questions
/ 0501 What is anchored — the file, or a hash of the file?
Only the SHA-256 hash is anchored; the file itself is never stored or transmitted to the registry.
02 Can I verify the receipt without contacting a service?
Yes — the receipt contains the anchor hash and timestamp; verification re-hashes the content locally and checks the chain, with no external lookup.
03 How is the registry itself tamper-evident?
Anchors are appended into a hash-chained registry with a signed root; altering any past entry breaks the chain and invalidates later receipts.
04 Can I anchor hashes in bulk?
Yes — the API accepts a batch of hashes and returns a receipt per entry, each chained into the registry.
05 What hash algorithm is used (SHA-256)?
SHA-256; digests are hex-encoded and receipts include the algorithm so verifiers never assume it.