The nommo Provenance Standard

This document describes how nommo records who made a creative work and who has held it, and how anyone can check that record without trusting nommo. It is written so that another platform, an archive or a museum could adopt the same method. Nothing in it is secret, and nothing in it needs nommo's permission to use.

It describes what is running today. Where the method has a limit, the limit is stated.

1. What the standard is for

A creative work in digital form can be copied perfectly, so a copy proves nothing about who owns it. What can be made trustworthy is the record: a statement of who made the work, who acquired it, and every time it passed to someone else.

A record is worth trusting only if three things are true:

1. Nobody can change the past unnoticed, including the body that keeps the record.
2. Anyone can check it, without asking the keeper to vouch for itself.
3. It says nothing it should not, about who a person is or where they live.

The standard is a way of meeting all three with ordinary tools and at almost no cost.

2. The terms used

• Work. The creative work itself: a song, a film, a book, an image, a lesson.
• Copy. One person's holding of a work. A unique work has one copy. A limited work has a numbered run of copies. Each copy has its own record.
• Object. A physical thing bought on nommo: a record, a printed book, a garment.
• Entry. One event in the life of a copy or an object.
• Chain. All the entries for one copy or one object, in order.
• Seal. A single fingerprint of every chain, lodged in public on a given day.
• Mark. The code printed on the card that travels with an object, leading to its chain.

3. The entry

Every entry records:

People are recorded by an internal identifier, never by name. The record can show that a copy changed hands without showing whose hands.

4. The chain

The fingerprint of an entry is a SHA-256 hash of all its fields together with the fingerprint of the entry before it. Each entry is therefore locked to its predecessor.

The effect is simple. Change any past entry and its fingerprint changes; the next entry no longer matches it; and so on to the end of the chain. Remove an entry, or slot one in, and the same thing happens. Anyone can recompute the fingerprints from the first entry to the last and see whether they agree with what is stored.

Rules:

• An entry is only ever added to the end of a chain. Nothing is edited and nothing is removed.
• Every chain is written through one routine, so that no entry can be made without its fingerprint.
• A field added to the standard later is only included in the fingerprint of entries that have it, so that older chains still check correctly.

The limit of the chain alone. It is evidence of tampering, not a barrier to it. Somebody with full access to the database could rewrite a whole chain from the start and recompute every fingerprint. The seal exists to close that gap.

5. The daily seal

Once a day:

1. The last fingerprint of every chain is collected: every copy of every work and every object.
2. They are put in a fixed order and hashed together into one root.
3. The root is combined with the previous day's seal and the time, and hashed again. This is the seal. Seals therefore form a chain of their own.
4. The seal is submitted to OpenTimestamps, a free public service run by independent operators, which fixes it into the Bitcoin blockchain.
5. Within some hours the submission is confirmed, and the proof is stored beside the seal.

From that moment, the statement "this exact set of records existed on this day" can be verified by anyone using any OpenTimestamps verifier. It does not depend on nommo's database, on nommo's word, or on nommo still existing.

So the threat the chain could not meet is met. A person who rewrote the records afterwards would produce a root that contradicts a seal already fixed in public, which they never controlled and cannot alter.

Notes for anyone adopting the method:

• The seal contains no personal information. It is a fingerprint of fingerprints.
• nommo holds no cryptocurrency and operates no wallet. The public ledger is used only as a clock that nobody owns.
• A seal waits honestly as "pending" until its confirmation arrives. It is never reported as confirmed before it is.
• If the daily job is missed, the next seal covers the gap. What is lost is precision about the day, not the integrity of the record.

6. Physical objects and the mark

An object has a chain exactly as a copy does. What it needs in addition is something on the object's side that leads to the chain. That is the mark.

• A code for each object, of the form NM-XXXX-XXXX-X. It uses an alphabet with no characters that can be misread off a printed card, and ends in a check letter that catches a mistyped one.
• A card carrying the code and a QR, which travels with the object. It names no owner, so that it passes on with the object.
• A public check. Anyone may enter the code and see the object's record: what it is, who made it, its number in the run, when it was first acquired, how many times it has changed hands, and whether its chain is intact.
• The owner's proof. A card can be photographed and printed again, so a code shows only that a record exists. The owner on record can display six figures that change every five minutes. The person checking types them in and is told yes or no. The figures are computed from the code, the time and a secret held by the keeper, so nothing is stored and nothing can be reused later.
• Signs of copying. Each check by an outsider is counted. A mark looked up far more often than one object changes hands is flagged. The mark of a refunded order reads as withdrawn.

The limits of the mark. It is on a card, not in the object: there is no engraving and no chip. Its strength is the owner's proof, not the card. And an object sold privately, outside the keeper's own resale, does not move in the record until the parties bring it back.

7. What may be shown, and to whom

8. What an adopter must do

A body may say it follows this standard if it:

1. Records every transfer as an entry in a chain, by the method in sections 3 and 4.
2. Never edits or removes an entry.
3. Seals all chains at least once a day against a public timestamp it does not control, and keeps the proofs.
4. Lets anyone check a chain and a seal without an account.
5. Names no owner in anything public.
6. States its own limits as plainly as this document does.

9. What the standard does not do

• It does not prove who made a work. It records the claim, and the keeper's review of it.
• It does not stop a file being copied. It makes clear who the copy belongs to.
• It does not say what a work is worth, and nothing in it is a statement of value.
• It does not replace a contract. What a holder is entitled to is a matter of the keeper's terms and the law.
• It is not a token and cannot be traded apart from the work it describes.

10. Checking nommo's own record

• Every seal nommo has made, with its fingerprint and its proof, is listed at nommo.live/institute/seals. Nothing there needs an account.
• A physical object can be checked at nommo.live/mark.
• A copy of a digital work shows whether its chain is intact on the work's own page and on its resale listing.
• The proof for any seal can be verified with any independent OpenTimestamps verifier.