Across protocol is a novel bridging method that combines an optimistic oracle, bonded relayers and single-sided liquidity pools to provide decentralized instant transactions from rollup chains to Ethereum mainnet.
Across gathers liquidity pools of ERC20 tokens on Ethereum to facilitate fast withdrawals of token deposits on Layer 2 (L2) networks like Optimism and Arbitrum. The deposits on Layer 2 are one-way and are sent by the L2 network’s slow native bridge to the pool on Ethereum, reimbursing liquidity providers. This can be thought of as the liquidity providers giving a short-dated loan on Ethereum secured by Layer 2 deposits.
To bridge the tokens, relayers post a bond along with the L2 deposit details, which allow withdrawals from the liquidity pool on Ethereum after a short challenge period. The relayer can also advance the money to the depositor and get reimbursed from the liquidity pool themselves after the challenge period. UMA’s oracle mechanism allows anyone to dispute invalid relays during the challenge period and claim the relayer’s bond if the relay was incorrect.
Depositors pay liquidity providers a fee based on the utilization of the pool for access to liquidity on Ethereum. Optionally, they may also offer a fee to incentivize relayers to validate their deposit, or they may relay the tokens themselves.
Instantaneous Liquidity.- Assets are bridged and available for use on the mainnet almost instantly.
Secure-Powered By UMA protocol. Transfers are secured by UMA's Optimistic Oracle, which is audited by OpenZeppelin and trusted by top teams to protect hundreds of millions of dollars in value.
Cheap- Relayers and liquidity providers are compensated with fees from users initiating transfers, but this fee is less than any other solution on the market.