Themis

Cross-chain vickrey auction powered by Hyperlane enabling you to launch your ERC721 collection with the most optimal auction design and allowing you to accept bids on any chain.

Background

A couple weeks ago, I came across the "sneaky" auction post by A16Z Research. On-chain auction has a focus area for designing robust market structure for your web3 protocols recently, be it NFT mints or early access to your token-gated platform. This particular design was interesting because it combined the CREATE2 opcode and state proofs to guarantee bid privacy for users without making them lock up more collateral than required for the bid. Plus, a vickey auctions is a blind second price auction which is acknowledged as closest to fair value auction or being an "optimal" auction. But there were a few things missing for this to a viable option for everyday drops and users (I'll use the example of Ticketmaster's botched release of Taylor Swift's tour tickets as a use case):

• the auctions are configured for one item and needed to be setup afresh for each item. If you wanted to sell 10k tickets, you'll to instantiate and conduct 10k auctionsn which is not feasible.
• the auction lives only on one chain which means users will need to bridge their assets to this chain and then place their bids. Here, you are introducing additional latency and immenient bridge risk.
• the auctions takes only ETH as collateral for the bids which is rather inflexible. Any auctions especially ones which are expected to be oversubscribed need to have arbitrary ERC20 collateralization feature.

These issues are why I started this project, to productionize the novel CREATE2 mechanism to be used for more and more auctions going forward.

How it works

Private or sealed bid auctions need to be a. private till everyone else has placed their bid and b. winner has enough collateral locked up to fulfil their commitment. Private bids obsecuate the bid amount and who person behind the bid.

We use the CREAT2 opcode similar to a16z's implementation. With the CREATE2, we can predict the exact address of the collateralized vaults and send them our bid amounts before initializing the actual contract. This way, it will look like any ordinary transfer of tokens to an address from the outside. This serves as a hash commitment for our bids and collateral we deposited into the predeployed vault. Since the bidder can't access the private keys of the vault, the collateral is locked until revealed. All this happens on the origin chain.

Contracts

src
├─ interfaces
│  ├─ ILiquidityLayerRouter — "Interface for dispatching and handling token transfers using an adapter"
├─ libs
│  ├─ Auction — "Library for formatting auction domain and address"
│  ├─ Bids — "Library for defining the min heap for storing top k out of n bids"
│  ├─ LibBalanceProof — "Library for proving balances at a certain hash"
├─ IThemis — "Abstract contract for defining events and custom errors"
├─ ThemisAuction — "Origin chain ERC721 compatible for storing bids and conducting vickrey auctions"
├─ ThemisController — "Remote chain contract for handling token transfers and revealing bids"
├─ ThemisRouter — "Extending Router and ILiquidityLayerRouter for dispatching and handling with callbacks and token transfers using an adapter"
├─ ThemisVault — "Remote chain contract for locking collateral deployed with CREATE2"

Usage

You will need a copy of Foundry installed before proceeding. See the installation guide for details.

To build the contracts:

git clone git@github.com:aroralanuk/themis-contracts.git
cd themis-contracts
forge install

Run Tests

In order to run unit tests, run:

forge test

Acknowledgements

These contracts were inspired by or directly modified from these sources:

• Auction-zoo
• Anonymous Vickrey Auctions On Chain

WIP