Verify ownership of data NFTs

The goal of the NFT Kit is to provide a simple library and web service for NFT-based access management. Therefore the ownership of NFTs, aligned with OCEAN protocols specifications, must be verified.

The library provides a VerificationService which exposed the method dataNftVerification that takes the following parameter:

• chain: the EVM-compatible chain name or chain ID

• factorycontractAddress: The address of the factory contract

• erc721contractAddress: The address of the custom contract

• account: The account to be verified

• propertyKey: The NFT meta data property key that should exist

• propertyValue: The NFT meta data property value that should exist

Verify data NFT

    val chain= Chain.ROPSTEN
    val factorycontractAddress= "0x13d474cc837549cd8106d6b945cf591a32a84e88"
    val erc721contractAddress= "0x0310aC2748616Ce399Ba83051DdE35126807c4DE"
    val account= "0xf31fc0d18a24c6ae4225a0d4eeb709ac0a18e993"
    val propertyKey= "color"
    val propertyValue="green"
    val verififcationResult= VerificationService.dataNftVerification(chain, factorycontractAddress, erc721contractAddress, account, propertyKey,propertyValue)

The following example shows an OCEAN Data NFT minted by a contract from our own deployed contract factory on MUMBAI.

Visit the

Architecture of data NFTs

Unlike typical ERC 721 tokens where a Smart Contract allows the creation of multiple tokens, Smart Contracts of data NFTs allow just one token per contract. Therefore, a Factory Contract serves as creator of a number of custom contracts which may have each one token minted at max. This architecture allowed the custom contracts to have individual rules, which provides a lot of flexibility compared to the traditional architecture.

The following graphic illustrates the Factory Contract, which serves as creator for several custom contracts (need to be registered first) that are bound to a data NFT.

A further notable difference to classical NFTs is that data NFTs don't make use of external storage solutions like IPFS. Data NFTs use on-chain meta-data, which has the advantage that meta-data remains persistent due to the nature of the blockchain. Nevertheless, it comes with the disadvantage that on-chain storage space is limited and costly.

You will learn how you can use the NFT Kit to verify the ownership and properties of Ocean protocol's (V4) ERC721 data NFT.

Ocean protocol V4 data NFTs have a specialized Smart Contract architecture to handle data or intellectual property related use cases. Therefore, the NFT Kit was extended with special interfaces to deploy contracts, mint tokens and most importantly to verify the ownership of data NFTs. Learn more in detail how things were implemented in the .

Getting Started

Deep dive

- How to use the NFT-Kit

- How to verify NFT ownership and properties in the metadata

- View NFTs via a Web-Wallet

- See how the Ocean Protocol was integrated into the NFT-Kit

Get started by choosing your system

Do you want to build using our APIs or add the NFT-Kits functionalities as a direct dependency in a Kotlin/Java application

API

Installation & Running the Project

Make sure you have Docker or a JDK 16 build environment including Gradle installed on your machine

git clone https://github.com/walt-id/waltid-nftkit.git

cd waltid-nftkit/

docker build -t nftkit .

docker run -p 7000:7000 -it nftkit

git clone https://github.com/walt-id/waltid-nftkit.git

cd waltid-nftkit/

gradle clean build

cd build/distributions/
tar xf waltid-nftkit-1.0.0.tar 
./waltid-nftkit-1.0.0/bin/waltid-nftki

Start Building

NFT | Verification - How to verify NFT ownership and properties in the metadata

NFT | Wallet - View NFTs via a Web-Wallet

Architecture - See how the Ocean Protocol was integrated into the NFT-Kit

Kotlin/Java SDK

Gradle

implementation("id.walt:waltid-nftkit:VERSION")

Maven

  <dependency>
        <groupId>id.walt</groupId>
        <artifactId>waltid-nftkit</artifactId>
        <version>VERSION</version>
   </dependency>

Required Maven repos:

https://maven.walt.id/repository/waltid/

Start Building

NFT | Verification - How to verify NFT ownership and properties in the metadata

NFT | Wallet - View NFTs via a Web-Wallet

Architecture - See how the Ocean Protocol was integrated into the NFT-Kit