NFT Bridge

Introduction

Non-Fungible Tokens or NFTs are increasing in popularity. Today, NFTs face similar challenges as (fungible) tokens: there are products and use cases for NFTs on various networks. Market places only support certain networks, games only support certain networks, etc.
Due to the high demand, in addition to the Token Bridge, the bridging for NFTs has also been implemented in the Cross-Chain Bridge v2.0. With this we reach a new level of interoperability by integrating not only fungible tokens, but also NFTs - allowing this important new asset class to become more fluid.

How it works

NFT Bridging works by way of having NFT tokens whitelisted and minted as “Bridged Collections” on the other networks. In general, an NFT gets locked in network A and the users gets a unique duplicate in network B. On the way back the duplicate NFT gets burned and the original NFT gets unlocked on network A. A technical description is available below.
In the first version, the bridging must be done by entering the NFT ID. In a later version, the usability for this will be improved.

NFT Collection Whitelisting

NFT Collection Creators can ask to be reviewed (scam protection) and whitelisted. After submitting this form, a representative will do so asap.
The listing of the collection is free of charge. Royalty handling will be discussed.

Protocol Incentive or NFT Bridging Fees

For the launch period, NFT bridging fees are $0.00.
At a later stage, the protocol incentive or NFT bridging fee will be a fixed amount of (to be determined; later with governance) - as the fee cannot be a % of the value, as the value of an NFT cannot be taken from an exchange. This NFT fee will fully be utilized to Buy-back-and-burn TXL, the token behind the project, as a compensation for TXL holders running the bridge network (in the future).

Technical Description

Technically, this is how NFT Bridging works: A user deposits an NFT into a Smart Contract of Network A. The NFT gets locked. Afterwards, the user has to get signatures from the oracles who will confirm that the deposit was made in network A. With these signatures, the user can call the same contract in network B where a duplicate NFT will be minted and sent to the user. If the user wants the original on network A back, the user needs to send the duplicate NFT to the bridge (where it gets burned), ask the oracles again for signatures to confirm that it happened and then call the contract in network A where the original will be released.
More technical details can be found in the Smart Contracts section of this GitBook.