ARC-0722: NFT Collection Registry

[pa-long]

ARC-0722

Title: Aleo NFT Registry
Authors: [email protected]
Discussion: ARC-0722 Aleo NFT Registry
Topic: Application
Status: Draft
Created: 2024-10-14

Abstract

The Aleo NFT Registry standard (ARC722) is a proposal for extending ARC721 standard, defining a registry for Non-fungible tokens on Aleo, similar to how ARC21 builds on ARC20 for fungible tokens.

However it comes with a challenge that does not exist for fungible tokens: how to support arbitrary on-chain data structure for NFTs?

The proposed solution is to allow multiple registry implementing ARC722, with each its own Data struct type, allowing abitrary on-chain NFT data.

Such an implementation of ARC722 can be found here, with Data defined as:

struct Data {
    metadata: field
}

Under that standard, NFT collections are identified by the unique pair: (registry_program_id, collection_id).

Enforcing Registry list

Since multiple registry will co-exist, we should decide on how we keep track of registry program list. Here are two propositions, but feel free to make any additional suggestions.

1. Explorers could maintain a list of valid ARC722 implementations.
2. Wallets could allow to add custom registry programs, similar to how MetaMask allows adding custom token contracts.

References

ARC-0721: NFTs with owner and data privacy
ARC-0021: Multi-Token Standard Program