‹ Catalogue

Checking the catalogue manifest

This folder holds a list of the works in the catalogue (catalogue-public.csv) and a timestamp proof for it (catalogue-public.csv.ots). The proof shows that this exact list existed no later than a certain date, because its fingerprint was recorded in the Bitcoin blockchain. Nobody, including the artist, can change the list afterwards without the change showing.

The lists

Each list has its own proof, and a newer list does not replace an older one. A work is proven to exist from the date of the earliest list that contains it. catalogue-public.csv and its .ots are copies of the newest pair.

• 2026-11-04: list, proof

What the list contains

For each published work: catalogue number, title, date made, medium, year, kind, dimensions, copyright, and two fingerprints (SHA-256) of the signed image: the pixel digest and the file hash. It does not contain prices or locations.

Check the date

1. Download both files from this folder and keep them with their original names and unchanged.
2. Open opentimestamps.org. Drop catalogue-public.csv.ots into the box first. Then, when the page asks for the original file, drop catalogue-public.csv.
3. Do not drop the CSV alone into the first box: that starts a new stamp instead of checking this one.
4. The page shows a Bitcoin block and a date. That is the earliest time the list is proven to have existed.

On the command line, with the ots tool installed: ots verify catalogue-public.csv.ots (the CSV must be in the same folder).

Check a work

• Find the work by its catalogue number (it is also on the certificate and written on the back of the work).
• Compute the file hash of the signed image you have: shasum -a 256 image_signed.png. It should equal the image-sha256 in the list.
• The image carries the artist's digital signature. The artist's SigStamp public key has the SHA-256 fingerprint 79770ef9faab912b9dbe4b0c78cd1b27a1eabf31b1138e5924a507f41d5d2e68, also printed on the certificate.

What this does and does not show

• It shows the list, and so each image fingerprint in it, existed by the proven date and has not changed since.
• It does not by itself link an image to a physical object. That link is the catalogue number written on the back of the work, the signed certificate, and this public record.
• The list is a snapshot. Works added later appear in a later, separately stamped list.