Support Linea Chain Bridge Routes

Point of Contact

Arthur Remy - Linea Core, Product Manager Cam O’Donnell - @daostratconsensys - Linea Growth, Product Manager

Proposal Details

Proposal Overview

The Linea core team proposes the integration of Across to Linea. The focus is establishing an efficient Across <> Linea bridge adapter to ensure seamless interoperability to the network. In collaboration with the Across core team, the Linea team has been working to ensure the new chain requirements and technical feasibility (more below in the implementation section) regarding the implementation of the bridge adapters. No technical hurdles prevent a successful deployment outside of the standard auditing processes.

At deployment, we propose the following route[s] be enabled:

• Token[s]: ETH, USDC, USDT, WETH, DAI, WBTC
• Route: Supported Chains <> Linea

Proposal Motivation & Benefits

Integrating Across aims to tap into the bridge volume from the expanding Linea ecosystem. This move will provide users and developers with efficient, cost-effective token bridging options, leveraging Across’ intent-based infrastructure. The goal is to enhance Across Protocol's market presence by offering crucial bridging solutions in a promising ecosystem.

Some of the benefits of integrating Across with the Linea ecosystem include:

1. Market Expansion – This integration enables Across to extend its reach and capture a larger portion of the bridge volume within the L2 space, specifically in the growing Linea ecosystem. Bridging volumes are expected to be > 6M/day. (numbers derived from native bridge monitoring).
2. Strengthened Partnerships – The collaboration enhances the synergy between Across and Consensys products, particularly through MetaMask and other Consensys verticles.
3. Volume – Target a market share of >20% of the bridge volume to Linea. These numbers will be monitored and shared with stakeholders quarterly.

Background

About Linea

Linea results from more than 20 months of R&D by Consensys, an Ethereum development company - the company behind MetaMask. The Consensys R&D team, known for their contributions to the zk space and active participation in the Merge built a zkEVM that offers EVM equivalence, scalability, and reduced transaction costs while maintaining Ethereum’s security guarantees through Zero-Knowledge Proofs. For comparison, this is similar to the Across zkSync deployment; however, Linea’s stack is bytecode equivalent to Ethereum.

Linea has seen consistent growth in TVL, reaching ~$200M on the network per L2Beat, and ~$85M in tracked protocols, according to DeFiLlama. This growth over six months signals an expanding ecosystem, further bolstered by ongoing activations and integrations with Consensys products. Numerous exciting product integrations are expected over the next 12 months. Notably, Linea is now a primary network in MetaMask. These are examples of how we are uniquely positioned to explore synergistic integrations across Linea, Consensys products, and Across. 🔥

Vortex Prover: A little technical, but super cool

What is particularly exciting about Linea is its ability to consolidate transactions and submit proofs to the Ethereum mainnet using a novel prover mechanism. This process enhances throughput and minimizes transaction fees while maintaining the inherent security of the Ethereum network.

Vortex, a cryptographic primitive under development at Consensys, aims to increase the performance of Linea. It leverages a novel type of zkProof called a recursive aggregation proof. This is based on Ring-SIS, a well-known premise from lattice-based cryptography. This proofing system enables the batching of transactions to increase the network’s throughput while reducing fees. Linea also employs zk circuits to conduct computations. These cryptographic circuits facilitate secure and efficient computations for the network.

Implementation

Timeline

The following key dates are targeted for this deployment.

| Topic | Dates| |------|------| |✅ Forum Post:| Feburary 13 - 20| |Governance Vote| Feburary 20| |Target Deployment| March 7 - 14| |LXP Campaign | March 7 - XX|

Technical Implementation

If approved, the technical implementation of this proposal will be led by core team members of Across, who will oversee the launch on Linea. A critical step in this process involves the Across <> Linea bridge adapter undergoing its audit, conducted by OpenZeppelin.

The Linea core team will be all hands on deck to assist with any required engineering resources and are actively collaborating with Across on engineering, technical discussions, and audit workstreams. This collaboration aims to align both teams on the technical nuances and ensure a smooth, efficient implementation process.

New Chain Requirments

Per the New Chain Requirements, Found in the Across Documentation, Linea meets the following requirements:

| Criteria | Description | Details | |----------|-------------|---------| | EVM Chain & Bridges | EVM chain with a canonical token and message bridge to mainnet. 30D MA TVL of chain > $75M | ✅30D MA TVL: ~$188M | | RPC Node Providers | ≥ 2 independent RPC node providers | ✅ 7 Private and 6 Public endpoints found here. | | Support Channel | Dedicated support channel with technical members and priority support for contract development and debug | ✅ Core Linea team has active support channels open directly with the Across core team. | | Bridging Volume | 30D MA bridging volume to/from chains on all bridges for tokens and chains that Across supports > $2M | ✅ 30D MA net bridging volume on native bridge > $6M | | Unique Bridging Addresses | 30D MA unique bridging addresses (by recipient address) to/from chain on all bridges for tokens and chains that Across supports > 1000 | ✅ 30D MA unique bridging addresses on native bridge + Orbiter > 1500/day | | Token Grant for Across DAO | Bonus: Token grant for Across DAO to distribute to users for transfers to new chain | 🟨 Linea is working with the Across team on setting up an incentive campaign, using Linea XP (LXP). LXP is a nontransferable ERC20 Point system. |

Additional Information

Security Considerations

The Linea adapter operates without any additional trust assumptions beyond those associated with our existing chain adapters. This ensures that the deployment process for Linea will be consistent with our previous experiences.

Further, the Linea stack proactively collaborates with top-tier security firms to perform comprehensive audits on all core contracts.

Please see Previous Linea audits at this link.

---

Next steps

The proposal will be in a seven-day governance vote to assess the Across community's willingness to deploy on the Linea zkEVM. Pending the outcome of this vote, the core teams will work to deploy the necessary tech and maintain transparency with the community.