Propose Hybrid Assets standard

aips/aip-hybrid-nft-standard.md

@@ -0,0 +1,246 @@
+---
+aip: (this is determined by the AIP Manager, leave it empty when drafting)
+title: Aptos Hybrid Assets Standard
+author: @gregnazario
+discussions-to (*optional): <a url pointing to the official discussion thread>
+Status: Draft
+last-call-end-date (*optional): 10/15/2024
+type: Ecosystem
+created: 10/3/2024
+updated (*optional): <mm/dd/yyyy>
+requires (*optional): <AIP number(s)>
+---
+
+# AIP-X - Aptos Hybrid Assets
+
+## Summary
+
+On Ethereum, we've seen the rise of ERC-404 / [DN-404](https://github.com/Vectorized/dn404) tokens. These tokens are
+standards combine a fungible token with a non-fungible token. This AIP proposes a standard for a Dn404 like experience
+on Aptos.
+
+This provides the ability to trade fungible assets for fractional ownership of an NFT directly in a liquidity pool. The
+goal here is to add liquidity to NFTs directly.
+
+### Out of scope
+
+We are not covering the specifics of liquidity pools, that should already be handled automatically by any existing
+providers.
+
+## High-level Overview
+
+From a high level, when a user deposits a set number of fungible assets into an account (let's say one whole asset),
+they will receive an NFT in their account. When a user drops below the set number of fungible assets, the NFT will be
+removed from their account. Additionally, NFTs can be transferred directly to other users, and the fungible asset will
+go with it.
+
+The following properties must hold:
+
+* There is a fixed set of NFTs and fungible assets, which have a 1:X relationship, where X is the number of fungible
+  assets per NFT.
+* There may be fewer NFTs than the ratio, but not more NFTs than the 1:X ratio.
+* Whenever an NFT is transferred, the fungible assets must be transferred with it.
+* Whenever the FAs are transferred, the NFTs must be burned or removed, and then minted or added to the new owners
+  accordingly.
+* When NFTs are transferred due to FA being transferred, there should be some randomness associated.
+
+## Impact
+
+NFT marketplaces and wallets will need to support the direct transfer of NFTs with fungible assets. This will allow them
+to ensure the properties above.
+
+## Alternative Solutions
+
+The alternative solution would be to have a non-standard way of creating these collections, which would cause
+fragmentation in nft marketplace, decentralized exchange, and wallet experiences.
+
+## Specification and Implementation Details
+
+A new contract will be deployed to `0xbbe8a08f3b9774fccb31e02def5a79f1b7270b2a1cb9ffdc05b2622813298f2a`, which will be a
+factory for future hybrid NFTs. The contract will be deployed to a resource account, specifically to allow anyone to
+mint collections from it. Additionally, users can create extensions to the collection by creating new contracts that
+use the base contract.
+
+When creating a collection, the user will need to provide the following:
+
+```move
+module hybrid_address::hybrid {
+    public fun create(
+        caller: &signer,
+        // Collection inputs
+        collection_name: String,
+        collection_description: String,
+        collection_uri: String,
+        // NFT inputs
+        hidden_nft_name: String,
+        hidden_nft_uri: String,
+        hidden_nft_description: String,
+        num_supply_nfts: u64,
+        num_tokens_per_nft: u64,
+        royalty_numerator: u64,
+        royalty_denominator: u64,
+        royalty_address: address,
+        with_properties: bool,
+        // FA Inputs
+        fa_name: String,
+        symbol: String,
+        decimals: u8,
+        icon_uri: String,
+        project_uri: String,
+        withdraw_function: Option<FunctionInfo>,
+        deposit_function: Option<FunctionInfo>
+    ): ConstructorRef {}
+}
+```
+
+This will then create a new collection, which will be co-located with the Fungible Asset metadata. The collection will
+then have a couple of new functions:
+
+### Minting
+
+The initial mint should exist to allow the creation of the collection. I've separated it from the initial collection
+creation
+to ensure that the entire collection can be minted, regardless of the number of NFTs.
+
+```move
+module hybrid_address::hybrid {
+    /// Mints FAs for the NFT collection, this is limited by the supply given earlier when creating the FA.
+    ///
+    /// Minting is limited to the owner of the collection.  Keep in mind that this is currently not limited other than the
+    /// maximum supply.
+    entry fun mint(
+        caller: &signer,
+        collection: Object<HybridCollection>,
+        receiver: address,
+        amount: u64
+    ) acquires HybridCollection, ObjectController, AssetRefs, HybridConfig, HybridOwnershipData {}
+}
+```
+
+### FA Transfer
+
+This will use dynamic dispatch to replace the NFTs directly in the collection. To save on gas, it will pull the NFTs
+from a pool, and assign a random seed. This seed will be used to reveal art with the `reveal` function. Prior to that
+the NFTs can be transferred directly as unknown, but with a name attached. Note that it cannot reveal art directly with
+randomness at this stage, or someone could do a test-and-abort attack.
+
+```move
+module hybrid_address::hybrid {
+    /// Transfer provides functionality used for dynamic dispatch
+    ///
+    /// This will not be called by any other functions.
+    public fun withdraw<T: key>(
+        store: Object<T>,
+        amount: u64,
+        transfer_ref: &fungible_asset::TransferRef
+    ): FungibleAsset acquires HybridToken, HybridConfig, ObjectController, HybridOwnershipData {
+        pre_withdraw_burn(store, amount);
+        fungible_asset::withdraw_with_ref(transfer_ref, store, amount)
+    }
+
+    /// Transfer provides functionality used for dynamic dispatch
+    ///
+    /// This will not be called by any other functions.
+    public fun deposit<T: key>(
+        store: Object<T>,
+        fa: FungibleAsset,
+        transfer_ref: &fungible_asset::TransferRef
+    ) acquires HybridCollection, ObjectController, HybridConfig, HybridOwnershipData {
+        let amount = fungible_asset::amount(&fa);
+        pre_deposit_mint(store, amount);
+        fungible_asset::deposit_with_ref(transfer_ref, store, fa)
+    }
+}
+```
+
+### Controlled transfer
+
+Transfers need to be overridden in order to ensure that NFTs are transferred with the fungible assets. This will need
+to be called directly by wallets, and other functions. There is no risk of randomness here, as the NFT will not change.
+
+```move
+module hybrid_address::hybrid {
+    /// This function replaces [`0x1::object::transfer`], as object transfer had to be disabled, since it doesn't support
+    /// dynamic dispatch.  Instead, this function should be used to transfer the NFT.
+    ///
+    /// Note: Transfer NFT will fail to transfer if you do not have enough FA in your primary fungible store.  If that's
+    /// the case, you will need to transfer FA first to the primary store.
+    public entry fun transfer<T: key>(
+        caller: &signer,
+        token: Object<T>,
+        receiver: address
+    ) acquires ObjectController, AssetRefs, HybridConfig, HybridOwnershipData {}
+}
+```
+
+### Reveal
+
+Transfers need to be overridden in order to ensure that NFTs are transferred with the fungible assets. This will need
+to be called directly by wallets, and other functions. There is no risk of randomness here, as the NFT will not change.
+The wrapping contract will need to save the reveal ref in order to handle the reveal.
+
+```move
+module hybrid_address::hybrid {
+    /// Reveals the collection, must have the reveal ref
+    public fun reveal(
+        reveal_ref: &RevealRef,
+        token: Object<HybridToken>,
+        new_name: Option<String>,
+        new_desc: Option<String>,
+        new_uri: Option<String>,
+        only_reveal_once: bool,
+    ) acquires HybridToken {}
+}
+```
+
+## Reference Implementation
+
+- https://github.com/gregnazario/aptos-hybrid-assets
+
+## Testing
+
+This will need unit testing across the standard, to ensure that there are no holes in the contract. Results will be in
+a week once it's completed.
+
+## Risks and Drawbacks
+
+- Potential drawback is adoption of marketplaces and wallets to use the new transfer function. With dynamic dispatch it
+  could be replaced with a more flexible solution.
+    - The mitigation plan is to provide help to wallets and marketplaces to adopt the new standard via a helper
+      function.
+- For future backward compatibility, depending on how the dynamic dispatch solution is provided, it may be necessary to
+  change the contract, or create a new contract altogether.
+    - The mitigation plan is to in the future provide a migration plan for future hybrid nfts.
+
+## Security Considerations
+
+This AIP doesn't impact the security of the network, but it does need to keep in mind to prevent test and abort attacks
+on randomness.
+
+## Future Potential
+
+In the future, pure dynamic dispatch would work well to replace this. Keeping in mind that, if there is a future with
+non-reversible transactions, we could have randomness in a single transaction.
+
+## Timeline
+
+### Suggested implementation timeline
+
+Implementation should only take one week of work, from the reference implementation.
+
+### Suggested developer platform support timeline
+
+Optionally, switching for determining which transfer function to use, may need to be added to the TS SDK, to ease
+onboarding of wallets. This would need probably a week of work.
+
+### Suggested deployment timeline
+
+This can be deployed entirely separately of the framework, and I'm not sure that it belongs directly in 0x4.
+
+It can be deployed in Devnet immediately, Testnet after a few weeks, and Mainnet after a few weeks after.
+
+## Open Questions (Optional)
+
+- How to handle custom staging of NFTs?
+- How to handle custom reveals of NFTs?
+- How to handle different behaviors of transfers on NFTs? Currently tied to one implementation.