Attest
Attest is the smallest complete Yano X product: a browser UI, a CLI, and a Java
client on top of the stock doc-trail state machine. It answers “did this exact
file exist, in this series, before this block?” with a certificate that a
third party verifies without trusting the node that issued it.
It adds no plugin, no new proof format, and no core change. Every check reuses a Yano primitive: the evidence bundle, the compact message proof, the height pinned state proof, and the script-anchor datum.
What a certificate proves
Section titled “What a certificate proves”| Check | Question | Verified by |
|---|---|---|
| Digest | Does the file hash to the attested SHA-256? | UI and CLI |
| Command binding | Did a chain member sign a doc-trail append carrying exactly this digest, series id, and reference? | UI and CLI |
| Message inclusion | Does the message sit at a fixed position of the stated block? | UI and CLI |
| Finality | Did the chain’s threshold of members sign that block? | CLI, against member keys you obtained independently |
| Anchor linkage | Does a Cardano state-thread datum commit to that block, state root, membership, and application id? | CLI, with the datum read from Cardano |
| Trail head | Did the series have the stated revision count and head digest at that block? | CLI |
The UI reports INTERNAL_CONSISTENCY_ONLY; the CLI reaches
CALLER_PINNED_ROOT with a members file and
INDEPENDENTLY_VERIFIED_L1_ANCHOR with an anchor datum. These are the ADR-037
trust levels used across Yano, so a certificate never claims more than its
inputs support.
What it does not prove
Section titled “What it does not prove”- Who the person behind the file was. The signer is the ingress member’s key; put authorship into the reference, which the command binds on chain.
- Anything about the content beyond its digest.
- A calendar time. Ordering comes from block height and, when anchored, the Cardano slot.
Modules
Section titled “Modules”| Artifact | Repo path | Role |
|---|---|---|
yano-x-attest-client | products/attest/client | Certificate format, node client, offline verifier. |
yano-x-attest-cli | products/attest/cli | yano-attest attest / certificate / verify / trail / status. |
yano-x-attest-ui | products/attest/ui | Portable static web application. Files never leave the browser. |
Who this is for
Section titled “Who this is for”- Teams that need proof of existence for contracts, reports, designs, or evidence files, without a notary service in the loop.
- Auditors who receive a certificate and the original file and want a verdict they can reproduce offline.
- Anyone evaluating Yano app chains who wants the shortest path from a running chain to a verifiable artifact.
Deeper reading
Section titled “Deeper reading”- Attest product guide — setup on the showcase or a fresh chain, CLI and UI walkthroughs, trust modes, exit codes, and troubleshooting.
doc-trailcapability — the state machine underneath.- State and proofs — how to read a proof result correctly.