🌉NFT Bazaar Infographics Hub | Possibility of Bridging NFTs across Layers

Problem

A problem faced within the Ethereum blockchain as well as Layer 2s is the segmentation of assets, especially NFTs. When an NFT is created on a Layer 2, the NFT is stuck on that layer. This leads to the problem of NFT silos, where NFT assets on Layer 2 cannot be withdrawn to Layer 1. Having a way to create and transfer NFTs across multiple layers is important in order to introduce NFT applications to Layer 2s.

Solution

Create a way to easily transfer NFTs across layers and reduce the gas requirements by minting the NFTs on Layer 2. This lets the user decide when they would like to withdraw their NFTs to Layer 1.

Initializing the NFT Contracts

The Owner will provision the L1_NFT_Collection with the deployed L2_NFT_Collection, specifying:

Address of the L2_NFT_Collection
Chain ID of the L2_NFT_Collection
Location of the NFT, mapping of the Chain ID by the NFT ID
Range of Allocated NFTs, e.g. #1–100, 60–61, etc.

Range is a unit of 1000 NFTs… rangeid 0 means NFT #0 to NFT #999.

Data Structure

mapping(chainid => address) addresses;
mapping(rangeid => chainid) range_loc;

Claiming the NFT on Layer 2

The User will claim the NFT, specifying the NFT ID. The L2_NFT_Collection contract on Layer 2 will verify the ID assignment (i.e. this Layer 2 owns the NFT) and mints the NFT on this rollup accordingly. Users can freely transfer NFTs within the rollup as normal.

Withdrawing an NFT

The User sends a transaction to the L2_NFT_Collection smart contract, initiating the withdrawal to a target recipient on Layer 1.
The NFT gets deposited into the L2_Deposit contract, which locks the NFT for later retrieval if necessary.
The Locked NFT triggers a cross-message to the L1_NFT_Collection which allows the designated recipient to mint/withdraw the NFT on Layer 1.
A new record in L1_NFT_Collection will be added to update the chain ownership of this particular NFT, data structure: mapping(id=>chainid) nft_loc; nft_loc always overrides range_loc. To determine the actual chain ownership of a NFT, the logic should check nft_loc first then range_loc if nft_loc[id] returns 0.
If the NFT was already previously minted on Layer 1 before, i.e. it is not the first time this NFT has been withdrawn to Layer 1, the user would get that NFT with the updated metadata, with its nft_loc updated.
The recipient will claim the NFT, specifying the NFT ID.

(Re)depositing the NFT on Layer 2

The User sends a transaction to the L1_NFT_Collection smart contract, initiating the transition to a target recipient on a target Layer 2 rollup.
The NFT gets deposited into the L1_Deposit contract, which locks the NFT for later retrieval if necessary.
The Locked NFT triggers a cross-message to the L2_NFT_Collection, which allows the user to mint/claim an existing NFT on Layer 2 by the NFT ID.
If the NFT was already created and was deposited to the target rollup, the user would recieve the NFT with the updated metadata.
L1_NFT_Collection will have nft_loc updated to reflect the updated chain ownership of the NFT.

Pros & Cons

Pros

Allows any user to claim an NFT on another Layer 2.
The User can withdraw the NFT on Layer 2 and have the equivalent NFT created on Layer 1 with no chance of duplication.
The User has the option to transfer their created NFT at any time from Layer 1 to Layer 2 and vice versa.
Allows one NFT project to extend to multiple rollups.
Easy and low cost initial setup.

Cons

The Owner has to create an equivalent NFT contract on the supported layers.
NFTs can only move from Layer 2 to the coordinator chain (Layer 1 in this case) and back, they cannot move from Layer 2 to Layer 2 directly.
Higher cost when moving NFTs among rollups because involvement of two Layer 1 transactions (withdraw and deposit)
Technical complexity to connect both Layers

About NFT Bazaar：

NFT Bazaar (https://nftbazaar.network) is one of the most-used aggregators that offering up to hyper-efficient NFT markets to benefit not only NFT token holders, but digital artists, musicians, gamers and all kinds of lovers as well, while providing one-stop NFT issuance, bidding and exchange platforms with ease.

The NFT issuance and transaction function has now been officially launched in May 2021, with updated compatibility functions of enabling other major protocols & smart contracts in September. NFT Bazaar has never failed to becoming your handy NFT aggregator as well as exchange platform full of vitality, with full access to the Ethereum ecosystem, and compatible for Polygon Network (Matic Mainnet) and more major projects issued elsewhere available for transactions with multiple major digital currencies, for instance, zUSD, Matic, USDT, etc.

At present, NFT Bazaar has collected 50,000+NFT contracts and 520,000+ on-chain transaction data, covering 9 categories such as art, collections, virtual world, sports, music, and games. The transaction data is updated in real time, which is far ahead of other similar platforms. In terms of transactions, it is estimated that the platform can support 1,000+ TPS and platform GMV will reach 1,000,000 US dollars/month. Although NFT Bazaar was just launched in 2021, it has fully achieved a marvelous average figural record of weekly UV 7,000+ and PV 10,000+, which further expected to reach MAU 50,000+ by the end of 2021 as to rank among the top 15 global NFT platforms.

Specifically for the Project Zero NFT series, NFT Bazaar has got the full support from three industry pioneers, Zerogoki, Duet Protocol and Muse Museum. If you want to know about us and our partnership networks, welcome to join us at:

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