# Loopring Markdown version of https://l2beat.com/layer2s/projects/loopring ## Summary **Warning:** This project is archived and no longer maintained. **Warning:** Loopring DEX was [sunset](https://x.com/loopringorg/status/2071253250725322987) and no longer accepts deposits. The Loopring Team plans to send out deposited assets directly to users. - Total Value Secured: $2.53 K (-4.73% compared to seven days ago; canonically bridged $2.53 K, natively minted $0.00, externally bridged $0.00; 0.00% with additional trust assumptions compared to the tokens involved and the Stage assigned to the project's canonical messaging bridge) - Stage: Stage 0 - Type: ZK Rollup - Purposes: NFT, Exchange - Host chain: Ethereum ### Risks - Sequencer failure: Force via L1 (sentiment: good) - State validation: Validity proofs (SN) (sentiment: good) - Data availability: Onchain (sentiment: good) - Exit window: None (sentiment: bad) - Proposer failure: Use escape hatch (sentiment: good) ### About Loopring is a ZK Rollup exchange protocol for trading and payments. ## Value Secured Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/loopring#tvs). - [TVS chart (JSON)](https://l2beat.com/api/scaling/tvs/loopring) - [TVS breakdown by token (JSON)](https://l2beat.com/api/scaling/tvs/loopring/breakdown) ## Activity Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/loopring#activity). - [Activity chart (JSON)](https://l2beat.com/api/scaling/activity/loopring) ## Onchain costs Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/loopring#onchain-costs). ## Liveness Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/loopring#liveness). ## Milestones & Incidents - 2026-06-28: [Loopring DEX sunsets](https://x.com/loopringorg/status/2071253250725322987). Loopring announces the DEX sunset, deposited tokens will be transferred to users. - 2025-07-31: [DeFi Closure Announcement](https://medium.com/loopring-protocol/loopring-defi-closure-announcement-e9270cccba4d). Loopring sunsets DeFi features to focus on the L2. - 2022-09-27: [DeFi Port is Live on Loopring](https://medium.loopring.io/loopring-l2-defi-port-cd6e811250a9). Dutch auctions, lending, and other DeFi functions can be performed on Loopring. - 2021-08-24: [Loopring Supports NFTs](https://medium.loopring.io/loopring-now-supports-nfts-on-l2-29174a343d0d). Loopring supports NFT minting, trading, and transfers. - 2020-12-02: [Loopring’s ZK Rollup AMM is Live](https://medium.loopring.io/looprings-zkrollup-amm-is-live-2f8251cd0fcd). Improved implementation, enabling gas-free instant swaps and liquidity changes. - 2020-09-22: [Loopring Protocol 3.6 Pre-release](https://medium.loopring.io/loopring-3-6-is-code-complete-and-security-audit-has-begun-68a642506e31). Enhancements in transfers, order-book trading and AMM swap. - 2020-06-06: [Loopring Supports Payments](https://medium.loopring.io/loopring-pay-is-live-zkrollup-transfers-on-ethereum-770d35213408). Support for ERC20 transfers is live on Loopring. - 2020-02-27: [Loopring DEX is online](https://medium.loopring.io/loopring-launches-zkrollup-exchange-loopring-io-d6a85beeed21). ZK Rollup trading is live, as Loopring launches their order book based exchange. - 2019-12-04: [Loopring ZK Rollup is live](https://medium.com/loopring-protocol/loopring-protocol-3-0-zksnarks-for-scalability-845b35a8b75b). Loopring Protocol 3.0 is fully operational with support for orderbook trading on WeDex. ## Risk summary ### Funds can be stolen if 1. a contract receives a malicious code upgrade. There is no delay on code upgrades (CRITICAL). ### Funds can be lost if 2. the proof system is implemented incorrectly. ### Users can be censored if 3. the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system. ### MEV can be extracted if 4. the operator exploits their centralized position and frontruns user transactions. ## Risk analysis ### Sequencer failure Force via L1 (sentiment: good) Users 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. ### State validation Validity proofs (SN) (sentiment: good) SNARKs are succinct zero knowledge proofs that ensure state correctness, but require trusted setup. ### Data availability Onchain (sentiment: good) All of the data needed for proof construction is published on Ethereum L1. ### Exit window None (sentiment: bad) There is no window for users to exit in case of an unwanted upgrade since contracts are instantly upgradable. ### Proposer failure Use escape hatch (sentiment: good) Users are able to trustlessly exit by submitting a Merkle proof of funds. ## Stage Loopring is a Stage 0 ZK Rollup. Loopring provides an orderbook decentralized exchange for spot trading. Arbitrary contracts are not supported. ### Stage 0 - [x] A complete and functional proof system is deployed. - [x] The project calls itself a rollup. - [x] State roots are posted to Ethereum L1. - [x] Inputs for the state transition function are posted to Ethereum L1. - [x] A source-available node exists that can recreate the state from Ethereum L1 data. Please note that the L2BEAT team has not verified the validity of the node source code. [View code](https://github.com/Loopring/loopring-subgraph-v2) ### Stage 1 - [ ] Principle: Compromising ≥75% of the Security Council should be the only way (other than bugs) for a rollup to indefinitely block an L2→L1 message (e.g. a withdrawal) or push an invalid L2→L1 message (e.g. an invalid withdrawal) with a <7d exit window. - [x] Users are able to exit without the help of the permissioned operators. - [ ] Upgrades executed by actors with more centralized control than a Security Council provide less than 7d for users to exit if the permissioned operator is down or censoring. - [ ] The proof system does not meet the minimum trusted setup requirements defined in the L2BEAT [trusted setup assessment framework](https://forum.l2beat.com/t/the-trusted-setups-framework-for-zk-catalog/381). - [x] Prover source code is published. ### Stage 2 - [ ] Upgrades unrelated to onchain provable bugs provide less than 30d to exit. ## Data availability ### All data required for proofs is published onchain All the data that is used to construct the system state is published onchain in the form of cheap calldata. This ensures that it will always be available when needed. **References** - [Introduction - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#introduction) ## State validation 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. ### ZK Circuits Loopring utilizes Groth16 for their proving system. The source code of the circuits can be found [here](https://github.com/Loopring/protocol3-circuits). **Risks** - Funds can be lost if the proof system is implemented incorrectly. ### Verification Keys Generation Groth16 requires a circuit specific trusted setup, so they run their own ceremony. The first phase is run using Powers of Tau ceremony. Some of the instructions on how to regenerate the verification keys can be found [here](https://github.com/Loopring/trusted_setup/tree/loopring-3.6.2). ### Validity proofs 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. **References** - [Operators - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#operators) ## Upgrades & Governance ## Updates Shown as an interactive chart or widget on [the HTML page](https://l2beat.com/layer2s/projects/loopring#updates). ## 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. **Risks** - 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 onchain. 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. **Risks** - Users can be censored if the operator refuses to include their transactions. However, there exists a mechanism to independently exit the system. **References** - [Forced Withdrawals - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#forced-withdrawals) - [Forced Request Handling - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#forced-request-handling) ## Withdrawals ### Regular exit The user initiates the withdrawal by submitting a regular transaction on this chain. When the block containing that transaction is settled the funds become available for withdrawal on L1. ZK proofs are required to settle blocks. Finally the user submits an L1 transaction to claim the funds. **References** - [Withdraw - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#withdraw) ### 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. **References** - [Forced Request Handling - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#forced-request-handling) ### 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. **References** - [Forced Request Handling - Loopring design doc](https://github.com/Loopring/protocols/blob/master/packages/loopring_v3/DESIGN.md#forced-request-handling) ## Permissions ### Ethereum #### Actors ##### LoopringMultisig Addresses: [0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97](https://etherscan.io/address/0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97) A Multisig with 2/3 threshold. This multisig owns BlockVerifier, ForcedWithdrawalAgent, and LoopringV3, and is the proxy owner of ExchangeV3. This allows it to arbitrarily change the forced withdrawal fee, change the Verifier address, and upgrade ExchangeV3 without delay. ##### ExchangeV3 Proxy Owner Addresses: [0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97](https://etherscan.io/address/0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97) The proxy owner can execute arbitrary code from the context of ExchangeV3, including sending tokens to arbitrary addresses. ## Smart contracts ### Ethereum #### ExchangeV3 Addresses: [0x0BABA1Ad5bE3a5C0a66E7ac838a129Bf948f1eA4](https://etherscan.io/address/0x0BABA1Ad5bE3a5C0a66E7ac838a129Bf948f1eA4#code), [0xB2de2bff671b03612a0Fa3340E0e0eE7e1C0a388](https://etherscan.io/address/0xB2de2bff671b03612a0Fa3340E0e0eE7e1C0a388#code) (Implementation (Upgradable)), [0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97](https://etherscan.io/address/0xDd2A08a1c1A28c1A571E098914cA10F2877D9c97#code) (Admin) Main Loopring contract. It was upgraded to the ProxyAdminExecutor implementation on 2026-06-29. Can be upgraded by: LoopringMultisig with no delay #### DefaultDepositContract Addresses: [0x674bdf20A0F284D710BC40872100128e2d66Bd3f](https://etherscan.io/address/0x674bdf20A0F284D710BC40872100128e2d66Bd3f#code) ERC 20 token basic deposit contract. Handles user deposits and withdrawals. #### LoopringV3 Addresses: [0xe56D6ccab6551932C0356E4e8d5dAF0630920C71](https://etherscan.io/address/0xe56D6ccab6551932C0356E4e8d5dAF0630920C71#code) 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. #### FastWithdrawalAgent Addresses: [0xec3Cc6Cf0252565b56FC7AC396017Df5b9B78a31](https://etherscan.io/address/0xec3Cc6Cf0252565b56FC7AC396017Df5b9B78a31#code) Auxiliary contract allowing users to process fast withdrawals. #### ForcedWithdrawalAgent Addresses: [0x52ea1971C05B0169c02a0bBeC05Fe8b5E3A24470](https://etherscan.io/address/0x52ea1971C05B0169c02a0bBeC05Fe8b5E3A24470#code) Auxiliary contract able to force withdrawals from L1 on behalf of users. #### BlockVerifier Addresses: [0x6150343E0F43A17519c0327c41eDd9eBE88D01ef](https://etherscan.io/address/0x6150343E0F43A17519c0327c41eDd9eBE88D01ef#code) zkSNARK Verifier based on ethsnarks library. Can be upgraded by: LoopringMultisig with no delay 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).