Loopring
$108 M
9.01%
...
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LoopringCoin V2 (LRC)
Ether (ETH)
USD Coin (USDC)
Wrapped liquid staked Ether 2.0 (wstETH)
Immutable X (IMX)
Rocket Pool ETH (rETH)
Wrapped BTC (WBTC)
Tether USD (USDT)
Mask Network (MASK)
ChainLink Token (LINK)
Ethereum Name Service (ENS)
Dai Stablecoin (DAI)
Decentraland MANA (MANA)
Matic Token (MATIC)
SAND (SAND)Milestones
DeFi Port is Live on Loopring
2022 Sep 27th
Dutch auctions, lending, and other DeFi functions can be performed on Loopring.
Loopring Supports NFTs
2021 Aug 24th
Loopring supports NFT minting, trading, and transfers.
Loopring’s ZK Rollup AMM is Live
2020 Dec 2nd
Improved implementation, enabling gas-free instant swaps and liquidity changes.
Loopring Protocol 3.6 Pre-release
2020 Sep 22nd
Enhancements in transfers, order-book trading and AMM swap.
Loopring DEX is online
2020 Feb 27th
ZK Rollup trading is live, as Loopring launches their order book based exchange.
Loopring ZK Rollup is live
2019 Dec 4th
Loopring Protocol 3.0 is fully operational with support for orderbook trading on WeDex.
Description
Loopring’s ZK Rollup L2 solution aims to offer the same security guarantees as Ethereum mainnet, with a big scalability boost: throughput increased by 1000x, and cost reduced to just 0.1% of L1.
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Risk analysis
State validation
ZK proofs (SN)zkSNARKS are zero knowledge proofs that ensure state correctness, but require trusted setup.
Data availability
On chainAll of the data needed for proof construction is published on chain.
Upgradeability
YesThe code that secures the system can be changed arbitrarily and without notice.
Sequencer failure
Force via L1Users can force the sequencer to include a withdrawal transaction by submitting a request through L1 with a 0.02 ETH fee. If the sequencer is down for more than 15d, users can use the exit hatch to withdraw their funds. The sequencer can censor individual deposits, but in such case after 15d users can get their funds back.
Proposer failure
Use escape hatchUsers are able to trustlessly exit by submitting a Merkle proof of funds.
Rollup stage
Loopring is a Technology
Validity proofs ensure state correctness
Each update to the system state must be accompanied by a ZK proof that ensures that the new state was derived by correctly applying a series of valid user transactions to the previous state. These proofs are then verified on Ethereum by a smart contract.
Zero knowledge SNARK cryptography is used
Despite their production use zkSNARKs are still new and experimental cryptography. Cryptography has made a lot of advancements in the recent years but all cryptographic solutions rely on time to prove their security. In addition zkSNARKs require a trusted setup to operate.
Funds can be stolen if the cryptography is broken or implemented incorrectly.
All data required for proofs is published on chain
All the data that is used to construct the system state is published on chain in the form of cheap calldata. This ensures that it will always be available when needed.
Operator
The system has a centralized operator
The operator is the only entity that can propose blocks. A live and trustworthy operator is vital to the health of the system.
MEV can be extracted if the operator exploits their centralized position and frontruns user transactions.
Users can force exit the system
Force exit allows the users to escape censorship by withdrawing their funds. The system allows users to force the withdrawal of funds by submitting a request directly to the contract on-chain. The request must be served within a defined time period. If this does not happen, the system will halt regular operation and permit trustless withdrawal of funds.
Users can be censored if the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system.
Withdrawals
Regular exit
The user initiates the withdrawal by submitting a regular transaction on this chain. When the block containing that transaction is proven the funds become available for withdrawal on L1. Finally the user submits an L1 transaction to claim the funds. This transaction does not require a merkle proof.
Forced exit
If the user experiences censorship from the operator with regular exit they can submit their withdrawal requests directly on L1. The system is then obliged to service this request. Once the force operation is submitted and if the request is serviced, the operation follows the flow of a regular exit.
Emergency exit
If the 15d deadline passes and the forced exit is still ignored the user can put the system into Withdrawal Mode, disallowing further state updates. In that case everybody can withdraw by submitting a merkle proof of their funds with their L1 transaction.
Permissions
The system uses the following set of permissioned addresses:
This address is the owner of the following contracts: LoopringIOExchangeOwner, ExchangeV3 (proxy), BlockVerifier, AgentRegistry, LoopringV3. This allows it to grant access to submitting blocks, arbitrarily change the forced withdrawal fee, change the Verifier address and upgrade ExchangeV3 implementation potentially gaining access to all funds in DefaultDepositContract. This is a Gnosis Safe with 4 / 7 threshold.
Those are the participants of the ProxyOwner.
Actors who can submit new blocks, updating the L2 state on L1.
The rollup owner can submit blocks, set rollup parameters and shutdown the exchange.
Smart contracts
The system consists of the following smart contracts:
Main Loopring contract.
Can be upgraded by: ProxyOwner
Upgrade delay: No delay
Contract used by the Prover to submit exchange blocks with zkSNARK proofs that are later processed and verified by the BlockVerifier contract. It allows to give or revoke permissions to submit blocks and to open block submission to everyone.
ERC 20 token basic deposit contract. Handles user deposits and withdrawals. This contract can store any token.
Contract managing LRC staking for exchanges (one Loopring contract can manage many exchanges). It also allows to change the forced withdrawal fee and the Verifier address.
zkSNARK Verifier based on ethsnarks library.
Can be upgraded by: ProxyOwner
Upgrade delay: No delay
Agent registry that is used by all other Loopring contracts. Currently used are FastWithdrawalAgent, ForcedWithdrawalAgent, DestroyableWalletAgent and a number of LoopringAmmPool contracts.
The current deployment carries some associated risks:
Funds can be stolen if a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL).