@valnivo_labs/verify

Checks that a document signed in a Valnivo Labs product is authentic, with nothing but the file.

Any document two people sign carries its proof inside the file. This finds it and checks that the text is the one both people signed, that every step of its history — proposed, signed, and whatever followed — is signed by the key it names, and that nothing was changed, reordered or removed. It makes no network request.

That check is the same for every kind of document. A kind can add rules of its own, and those are checked for the kinds listed below; the first is Valnivo's loan between two people, saved as a PDF from Valnivo.

npx @valnivo_labs/verify document.pdf

import { checkFile } from '@valnivo_labs/verify'

const result = await checkFile(new Uint8Array(bytes))
result.outcome // 'holds', 'not-authentic', 'no-proof' or 'unknown-kind'

What "holds" means, and what it does not

It holds: the document is the one its signatures cover, and nothing in it has been changed.

It does not show that the history is the one Valnivo recorded, rather than one somebody built with signing keys of their own — the keys are made on each person's device. Valnivo keeps a public record of every history, and a check against it answers authentic: pass a reader for that record as the second argument of checkFile, or use valnivo.eu/check.

A proof is evidence of what two accounts signed. It is not a qualified electronic signature, and it does not by itself make an agreement legally binding.

Without this code

PROOF.md writes the format down in full — where the proof is in the file, how it is encoded, and every hash and signature — so the same check can be redone with any SHA-256 and ECDSA P-256 implementation. The test in tests/ does exactly that with node:crypto, from the document alone.

checker/valnivo-checker.html, in the repository, is the same check as one page that runs in a browser with no connection: its own policy forbids every request.

Official copies

Only these are Valnivo Labs's:

• valnivo.eu/check;
• this repository and its releases;
• @valnivo_labs/verify on npm, published from this repository with provenance.

Anybody may copy and change this code, and a changed copy can be made to say that any document holds. It cannot change the document: the same file checked with an official copy, or by a checker written from PROOF.md, still gives the true answer. Before relying on a valnivo-checker.html somebody gave you:

• compare its SHA-256 with the one on the latest release and on valnivo.eu/check — sha256sum valnivo-checker.html, or on Windows certutil -hashfile valnivo-checker.html SHA256 — or simply choose the file on valnivo.eu/check, which compares it for you;
• gh attestation verify valnivo-checker.html -R valnivo-labs/verify shows it was built by this repository's release workflow.

Apache-2.0 grants no right to the Valnivo name (§6): a changed copy may not present itself as Valnivo's.

Building the checker

checker/ is the offline checker's source exactly as valnivo.eu builds it, with esbuild pinned to the same version, so npm run build:checker makes the same bytes. The release workflow refuses to publish if they differ from the committed file or from what valnivo.eu serves.

Kinds of document

Every document is checked for everything above. These kinds also have their own rules checked:

| Kind | What it is | Its own rules | |---|---|---| | labs.loan | Money one person lent another, in Valnivo | repayments and their confirmations, who may close it and with which outcome, no interest and no field beyond its own |

A document of any other kind is reported as unknown-kind, with signaturesHold saying whether everything every kind shares holds.

Issued documents

A document can also be issued: signed once by Valnivo Labs or one of its products, with a key that is the issuer's alone, and checked against that issuer's pinned public key rather than a record (PROOF.md §7). The first kind is labs.timestamp: the issuer's signed statement that a file's SHA-256 existed at a time — the issuer is sent the fingerprint and never the file.

import { checkFile } from '@valnivo_labs/verify'

const result = await checkFile(stampBytes, undefined, { subject: fileBytes })
result.outcome // 'issued', 'other-file', 'unknown-issuer', 'key-revoked', 'outside-key-validity' or 'not-authentic'

ISSUERS is the pinned list; the published one is at https://valnivo.eu/.well-known/valnivo-labs-issuers.json, and only that one learns of a revocation. An issued time is the issuer's own claim, and a timestamp says nothing about what the file says or who holds it. It is not a qualified electronic seal.

Also exported

• @valnivo_labs/verify/signing — a document two people sign, of any kind: its canonical form, fingerprint, signed history and proof.
• @valnivo_labs/verify/loan — one kind of signed document: money one person lent another.

Licence

Apache-2.0. Copyright 2026 Valnivo Labs. Valnivo Labs is a trade name, not a registered company.