The Discovery of Galaxy Joa — zkNFT - Kevin Leffew - Medium

May 10th, 2022

Today, we are excited to announce the drop of Brendan Murphy’s airdrop landscape collection, titled “The Discovery of Galaxy Joa”. This collection contains 33 unique landscape images envisioned by Brendan, that represent sightings of the spaceman as he executes his Mission.

This collection has been minted on zkSync, an ethereum zero-knowledge rollup (zk-rollup). Zero-knowledge rollups are a new kind of distributed computer that separates state from execution on the blockchain using a cutting-edge cryptographic technique called zkSNARKs (https://blog.ethereum.org/2016/12/05/zksnarks-in-a-nutshell/)

What is zkSync?

zkSync represents the cutting edge of ethereum scaling technology and enables ethereum to scale by over 1000x (while providing greater decentralized security guarantees then more centralized, big-block chains like Solana or BSV).

For the lucky winners of the raffle, the minted NFT can easily be moved onto main net in a gas efficient way. At the time of writing, it only costs about $0.40 USD (as of 12/16/21) to move the across nft across addresses on zksync. Compare this to a standard $40 gas fee when not using zk-rollup techniques, and the economic+security benefits are obvious.

Each of the winners has also received Eth to cover the gas fees for the withdrawal to L1, if you wish to bring the asset to any erc721-compatable app, like OpenSea.

Zero-knowledge rollups are a new kind of distributed computer that separates state from execution on the blockchain using a cutting-edge cryptographic technique called zkSNARKs

Creating a custom NFT Factory Contract for zksync

Carlos Beltran (europa-dev) wrote the BoonjixJoaFactory, an ethereum contract which registers the asset with zksync’s governance contract. This contract deviates from the standard zkNFT factory (https://zknft.xyz/) and enables the registration of a unique storage URI (outside of an ipfs CID) so that minter can register their asset on decentralized storage networks and web-based CDNs (in our instance Storj DCS).

The contract is publicly viewable via etherscan, and available here:

The `BoonjixJoaFactory` contract implements `ERC721` and the required `mintNFTFromZkSync()` function which does the minting of a given token from l2. One thing to note is that we do not reuse the provided `tokenId` and instead rely on the token id recovered from `contentHash`. We do use a counter, though, but only to keep track of the current number of tokes minted (see `totalSupply()`).

The schema for tokenURIs are as follows:

{baseURI}/{bucket}/metadata/{tokenId}.json

An example of this is as follows: https://link.us1.storjshare.io/raw/SOME_HASH/boonji-joa/metadata/1.json

Structuring a fair Snapshot and Selection

In order to structure a fair snapshot and selection for the winners of the 33 pieces in Bendan Murphy’s collection, “The Discovery of Galaxy Joa” — we first recorded a snapshot of eligible Boonji Project collection tokens via The Graph.

Verifiable Randomness for Selection with Chainlink

To determine the winners of the “Discovery of Galaxy Joa” landscape NFT raffle, we selected 33 eligible addresses using Chainlink’s VRF (Verifiable Random Function).

For more information around how this technology works, and enables probably fair and random selection for ethereum contracts, check out: https://docs.chain.link/docs/chainlink-vrf/

Join the Boonji Discord or navigate to our Githu to find the winners: https://github.com/europa-dev/zksync-airdrop-raffle

Decentralized Object Storage with Storj DCS

As always, all the image metadata is stored on the decentralized cloud using Storj DCS.

This means that object data is erasure-coded and distributed across a diverse set of uncorrelated nodes on Storj DCS (Decentralized Cloud Storage)

Storj DCS decentralizes object storage, reducing security risks- and increasing retrieval performance

Scalable Innovation in Web3 and Digital Art

From a science and technology standpoint, this is the first time zero-knowledge rollups, Storj DCS, and chainlink VRF have all been integrated into a web3 solution at scale — meaning the Boonji Communiji is continuing to make history at the intersection of web3 and fine art.

If you are a lucky winner of the Landscape Drop — you can access the NFT by navigating to https://wallet.zksync.io/ and activating your wallet. You can move the NFT around the rollup or easily withdraw it to Ethereum to list it on OpenSea or interact with ERC721 compatible smart-contract dApps.