Cross-Chain NFT to OpenSea

Goal

• bridge collectibles to and from OpenSea (see #ONEquest)
• a bridge to/from Enjin Efinity and wallet supports

Cross-rollup NFT wrapper and migration ideas

The NFT ecosystem is growing rapidly, and it's a significant part of the Ethereum chain's gas consumption. The youth and relative lack of entrenchment of the ecosystem, as well as the greater need to avoid high fees due to the non-financial nature of a large part of the NFT sector, makes it a prime target for moving to layer 2.

ethresear.ch

Immutable X Concepts

There are three core components to the Immutable X stack: the ZK-Rollup scaling engine, Link and the APIs. These components work together to lower the barriers of entry in the NFT space for developers and users, and enable instant trade confirmation, massive scalability, gas-free minting and trading...

docs.x.immutable.com

Cross-chain NFT bridge · Issue #72 · harmony-one/bounties

Description cross-chain NFT bridge Harmony Ethereum, Harmony BSC Context A Cross-chain NFT bridge (ERC721/ERC1155) can increase the liquidity of NFTs across multiple chains. With the booming NFT market right now, it is a highly s...

github.com

Cryptology ePrint Archive: Report 2019/1128 - SoK: Communication Across Distributed Ledgers

SoK: Communication Across Distributed Ledgers Alexei Zamyatin and Mustafa Al-Bassam and Dionysis Zindros and Eleftherios Kokoris-Kogias and Pedro Moreno-Sanchez and Aggelos Kiayias and William J. Knottenbelt Abstract: Since the inception of Bitcoin, a plethora of distributed ledgers differing in design and purpose has been created.

eprint.iacr.org

Weekly Update

• 10/25: bridge code has been merged, and ready to launch on Mainnet by end of this week.
• 10/18: ERC1155/HRC1155 bridge support of ETH is on testnet, @Ganesha Upadhyaya and @Yuriy M are reviewing the PR. The opensea verification support will be added this week.
• 10/06: ERC721/HRC721 bridge to/from Ethereum was in testing. ERC1155/HRC1155 is being worked on right now. A few engineers have shown interest and are working on the bridge.
• 09/28: We are making progress on the cross-chain NFT. Cross-chain HRC721 is working in local test net based on the comments from the bounty. 1155 support is on the way. The screenshot of the harmony to ethereum 721 support.

• 09/15: a few teams are interested in working on this bounty to support 721/1155 for cross-chain.

Updates

• Bridge frontend extension for NFTs
• https://github.com/harmony-one/ethhmy-bridge.frontend/pull/125
• Bridge backend extension for NFTs
• https://github.com/harmony-one/ethhmy-bridge.appengine/pull/43
• Bridge smart contract extension for NFTs
• https://github.com/harmony-one/ethhmy-bridge/commit/1651416f346877f4a18ad7580faa1a411bb02fd0

Related works

immutable-x:

• immutable-x is a layer-2 (zk-rollup based) solution targeted towards fast/cheap NFT trading.
• immutable-x api (https://docs.x.immutable.com/reference#application-1): developers do not need to interact directly with smart contracts (for minting to trading to transferring), but use simple API calls.
• immutable-x sdk (called link): Typescript SDK implementation for better partner integrations (works directly with web3 wallets like metamask).
• immutable-x shared orderbook: backend for assets (similar to opeasea) provided by immutable-x such that partners building marketplaces can directly utilize it.
• nft metadata: allows two types of metadata for nfts: 1) immutable (user upload nft image and immutable-x creates ipfs hashes and links the tokenURI), 2) mutable (user provide tokenURI, which user can change later)
• nft metadata allows additional properties to be passed in the metadata json.

Relevance to our crosschain-nft platform

• erc721 bridging from/back-to ethereum: our nft bridging uses same logic, where erc721 gets locked to bridge contract on ethereum and same tokenId gets minted to hrc721 contract that is mapped to unique erc721 contract.
• hrc721 bridging from/back-to harmony: not supported yet. but we could do: for any nft (hrc721/1155) originally minted on harmony, our bridge can allow them to be moved over to ethereum using two options: 1) deploying and minting as erc721: in this case, a new contract is deployed if an erc721 contract for the hrc721 does not exists yet. the cost will be bared by the user. and then corresponding mint for the tokenId is done. 2) mint into a generic erc1155 (like davinci): no new contract is deployed, user's hrc721 tokenIds gets mapped to erc1155 tokenIds. in this case, no cost for initial contract deployment, only minting cost.
• nft metadata: when the user locks erc721, horizon bridge mints corresponding hrc721 tokenIds with tokenURI same as erc721 tokenId tokenURIs. Further, bridge allows hrc721 owner to change tokenURI. when user bridges hrc721 to ethereum, same method can be used.
• nft backend: todo...