Develop more RGB21-interfacing schemata

[dr-orlovsky]

• Collections of NFTs ("unique digital collection" or UDC)
• Fractional NFTs ("unique fractional digital asset" or UFDA)
• Collection of fractional NFTs ("nonfungible collectables" or NFC)

Main challenge: implement proper AluVM verification scripts

[dr-orlovsky]

CC @cryptoquick @crisdut @zoedberg @fedsten

[zoedberg]

Proposed schemas make sense to me.

Moreover our team would like to propose a change to the RGB20 interface. By adding optional medias and previews it would be possible for us to implement a schema similar to our previous RGB121, that we propose to name CDA (Collectible Digital Assets).
The schema will be very similar to the NIA one but will allow an optional media and an optional preview. This should open interesting use cases like the possibility to add a logo or attach a PDF file to an asset.
If this proposal sounds good to you @dr-orlovsky I will open a PR with the necessary changes.

[dr-orlovsky]

@zoedberg we had this discussion with @fedsten and @giacomozucco back in 2020 and they were proposing to have fungible token media not be a part of the contract. The reason for that is that they are volatile, and may be provided by different vendors (for instance dark backgrounds may require different assets, or they may take different sizes, shapes etc). Thus, RGB20 does not include media for tokens - and instead, it should be a part of non-committable data (like Supplement).

[fedsten]

I must admit that I do not remember much of our 2020 discussion, but I do believe there are several use cases that we may not have considered at the time. For example security tokens may want to attached scans of analogically singed legal documents and/or visual representations of the real world asset (e.g. the cadastral plan of a real estate asset, the picture of a tokenized physical artwork etc).

Personally I do not see any drawback in adding an optional media attachment, but in not supporting it I see the risk of limiting some potentially interesting use cases.

[dr-orlovsky]

I propose to continue the discussion on RGB20 changes in https://github.com/orgs/LNP-BP/discussions/160 where it belongs (since it is a change to the standard and not a question of RGB21 implementation).