Provenance the owner keeps.

The problem

Moving precious metals into vaulted custody means documenting every piece. The custodian requires photographs and a packing list, and supplies no standard for either — no template, no field list, no stated relationship between the pictures and the rows.

So the owner keeps a folder of photographs and a spreadsheet, and reconciles them by hand across a long, repetitive session. The error is rarely in reading a scale. It is in the correspondence between two artifacts maintained separately: four 100 g bars from four refiners differ in one field and a logo; two bars of the same design and different masses photograph almost identically. A single omission does not produce one wrong row — it shifts every row after it, and both documents still look internally fine.

That list is then mandated, exchanged, relied upon, and editable by anyone at any time with no way to tell.

See it work

3:49 — capture on a phone, confirm on a desktop, attest on Algorand mainnet. Watch on YouTube

What Pyx does

1. The record is built from the photograph

   A photograph's SHA-256 is a field inside the item record, and the record's leaf hash covers both. There is no second artifact to drift out of step, because there is no second artifact.

2. The operator confirms every value

   Nothing is auto-committed. Fields are confirmed one at a time, and editing a value withdraws its confirmation — so no signature can cover a number nobody looked at.

3. One signature covers the whole holding

   The records are hashed into a Merkle root, and a notary signs a statement that it observed that root at that time. Priced per manifest, not per item.

What an attestation proves

That is the whole claim, stated the same way everywhere it appears. A provenance record that overstates itself is worth less than none, because the first counterexample discredits every record ever issued.

Nothing leaves your machine

No record and no photograph is transmitted. What reaches the notary is a 64-character root and a count of items:

Your archive stays on your own disk, in plain files, encrypted at rest with a key derived from a recovery phrase only you hold.

Prove one item, publish nothing else

An owner showing an insurer, a customs officer or an executor that they hold bar 47 must not thereby publish the other 199. Pyx writes a folder containing that one record, its inclusion proof, its photographs, and a standalone verifier. The proof carries sibling digests only, and a digest does not reverse.

The recipient opens the verifier in any browser. They need no account, no software of ours, and no payment — verification is free and stays free. The construction is published so anyone can re-implement it, which is the point: a verifier supplied by the party being checked is a courtesy, not evidence.

Status

Pyx is a working proof of concept, demonstrated end to end on Algorand mainnet with real settlement. The on-device classifier that proposes a piece's form and metal is a research build, trained on catalogue photography that was never licensed for the purpose; it proves the pipeline and is not part of a shipping product. Surface fingerprinting — binding a record to a specific physical object rather than to a description of one — is open research and is deliberately not claimed here.