Cryptographic Digital Art Tokens, a concept

Hi folks. I'm posting this in ~creative because I want to see what other artists think of it; the technical side is important too, but artists and art are the focus of this project.

Cryptographic Digital Art Tokens are a concept I've been working on for a while, to provide some of the benefits of crypto tokens without perpetuating the harm they create.

CDATs are not NFTs. They are not designed to facilitate investment, but rather collection. They do not use a blockchain and do not rely on distributed consensus at all. Instead, they use traditional cryptography to validate the ownership of art.

How CDATs Work

Let's say an artist Adam creates a piece of art called One. He decides he wants to sell a CDAT of One, so he creates a CDAT key and publishes his public key on his website, adam.art.

A collector, Beth, decides she wants to buy One. She e-mails Adam and they agree on a price, and exchange keys; once she has paid, Adam sends Beth a CDAT, which he has signed. Beth then cross-signs the CDAT and sends it back to Adam. It ends up looking like this:

=== CDAT DATA ===
Artist: Adam <adam@adam.art>
Collector: Beth <beth@betawork.codes>
Date of Sale: 2021-12-08T19:50:56Z
Title: One, a Digital Story
Work ID: art.adam.one
Cover Hash: e82c294938320bf4fab56970f52e1ddf
Work Hash: 3179c999f1d4fab4bcc8a57bca1c9d8c
Artist Key Fingerprint: c634d0420f825b91
Collector Key Fingerprint: 3b2e3bbf91ec96c2
=== CDAT SIGN ===
Artist Signature: YTtsc2tkamY7bHNramY7bGtqZDtsa2pmYTtsZGt...
Collector Signature: cXdpZXVwcXdpeXR1djtsbmFvdWNuZWN2cHdl...
=== CDAT META ===
Cover URL: https://adam.art/images/one-cover.jpg
Work URL: https://adam.art/art/one.zip
Artist Key URL: https://adam.art/static/cdat.key
Collector Key URL: https://betawork.codes/
=== CDAT OVER ===

In an ideal world, with all the software enablement I want to do, Beth would be able to take this token and put it in a digital gallery or on her website, where the art piece, and her ownership of it, would be proudly displayed for all to see in a user-friendly, beautiful format.

Structure

The CDAT has three sections - DATA, which is signed, META, which is not, and SIGN, which contains the CDAT's cryptographic signatures. Hashes and key fingerprints are in the DATA section, but URLs are in the META section, which means they can be changed later; artists and collectors can re-host their art and keys, so long as the files' hashes or fingerprints remain exactly the same.

Semantics

Because the CDAT is cross-signed, anyone can see that both Adam and Beth have agreed to the sale. Assuming the signatures and keys all check out, Beth can now prove to people that Adam sold her his art, and Adam can prove that Beth bought it.

Implementation

In order for this interaction to work, we technically need only existing technology: you can validate such things with GPG and some manual reordering. Ideally, though, we'd have a few tools:

• A CDAT validation program. This should include a command line program and a GUI (maybe even a mobile app?), and would validate the following information:
  • The given signatures are valid and correct for the given CDAT.
  • The keys used to sign the CDAT match both the given fingerprints and identities.
  • The linked key URLs, if any, in fact point to the indicated keys.
  • The linked art and cover URLs, if any, in fact point to files with the given hashes.
• A CDAT creation program. This should include a command line program and a GUI. It would take as input the relevant keys and names, provide a way to set the date, and ensure that everything relevant is online at the given URLs.
  • This program would be used by both artists (to create CDATs) and collectors (to cross-sign CDATs).
• A CDAT hosting service. Obviously there could be more than one of these, and people could host their CDATs and art on their own machines - that's decentralization, baby! - but it would be very nice to be able to host CDATs, art, and keys for free or a nominal fee.

This would be a great start, but in order to really kick-start the ecosystem, it would be nice to provide some additional enablement software, such as:

• A drop-in HTML embed that uses client-side JavaScript to display and validate CDATs on a website.
• A browser extension which validates CDATs found on arbitrary websites, on the user's request.
• A self-hostable CDAT gallery for artists and collectors which displays who owns what, and which art pieces are still for sale.

Please let me know if this idea is interesting to you, and ask any questions/leave comments!