Aptos on-chain NFT cross-chain implementation and operation guide

The NFTs on the Aptos blockchain have now realized cross-chain functionality with other chains. This article will detail the implementation principles of this feature and the user operation methods.

The Working Principle of the NFT Cross-Chain Bridge

The NFT cross-chain bridge supports the transfer of NFTs between multiple supported chains while retaining their metadata. When an NFT is transferred from the original chain, the process is as follows:

1. NFT is locked in the cross-chain bridge smart contract;
2. Mint an equivalent wrapped NFT in the corresponding collection on the target chain;
3. The wrapped NFT has the same name and appearance as the original NFT, and its functionality is consistent with other NFTs on-chain. On EVM chains, the wrapped NFT is an ERC721 token; on Solana, they are SPL tokens with Metaplex metadata; on Aptos, they are instances of the Aptos token standard.

The uniqueness of packaging NFTs lies in the ability to send them back to the original chain and unlock the original NFT. For example, an NFT originating from Aptos can be cross-chain to Ethereum, sold on a trading platform, and then transferred back to Aptos by the new owner.

Support cross-chain to Aptos chain

Currently, users can transfer NFTs from Arbitrum, Aurora, Avalanche, BSC, Celo, Ethereum, Fantom, Karura, Klaytn, Moonbeam, Oasis, Optimsm, Polygon, and Solana cross-chain to Aptos, and vice versa.

It is worth noting that some high-end NFTs, including dozens of Cryptopunks and a Beeple piece, have been transferred to Aptos through cross-chain protocols.

Introduction to cross-chain protocols

Cross-chain protocols are interoperability protocols that allow projects to build on top of their universal messaging layer. It connects multiple chains, including Ethereum, Solana, BSC, Polygon, Avalanche, Algorand, Fantom, Karura, Celo, Acala, Aptos, and Arbitrum.

The protocol achieves cross-chain functionality by sending messages between different chains. These messages are observed and verified by the guardian network of nodes, and once verified, they are submitted to the target chain for processing. This simple messaging mechanism allows users to interact with cross-chain decentralized applications, transfer cross-chain assets, or access cross-chain data.

Currently, the total transaction volume of the protocol has exceeded $3.5 billion, successfully transmitting hundreds of millions of messages, with millions of messages submitted daily. More than 60 protocols are built on top of its universal messaging layer.

Aptos on-chain NFT cross-chain operation guide

1. Access the cross-chain bridge interface.

2. Choose the source chain and target chain, for example, cross-chain from Arbitrum to Aptos.

3. Select the NFT to be cross-chain, click confirm and sign through the wallet.

4. After the cross-chain is completed, if you need to transfer the NFT back to the original chain, click "redeem".

In this way, users can easily transfer NFTs across different chains, providing more possibilities for the circulation and use of NFT assets.