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Astar <-> zkEVM Bridge

Overview​

LayerZero integration functionally connects the EVM on Astar parachain to the zkEVM on Ethereum. This takes the form of two smart contract-based endpoints that allow the chains to send messages to one another other.

Bridge ASTR on mainnet​

LayerZero has a standard for synthetic assets that can be locked on a source chain and minted on another called Omnichain Fungible Token or OFT, which we will refer to going forward.

For this walkthrough, on the Astar side, the contract is NativeOFT, which acts as an ERC20 wrapper contract (the function is payable) that will be used to send a cross-chain message to the OFT contract on zk Astar to mint ASTR, otherwise known as LayerZero (synthetic) ASTR.

On the Astar zkEVM side, the contract is OFT, which acts as the ERC20 ASTR synthetic asset on Astar zkEVM, which exist in a 1:1 ratio with its NativeOFT counterpart.

ContractNetworkAddress
OFT NativeAstar0xdf41220C7e322bFEF933D85D01821ad277f90172
OFTzkEVM0xdf41220C7e322bFEF933D85D01821ad277f90172

Bridging ASTR​

note

Token bridging will be integrated to Stargate UI https://stargate.finance/transfer shortly to make it easier for users to bridge tokens.

To facilitate token transfer, we have provided a sample repository containing a utility script:

  1. Fork the Repository

  2. Install dependencies by running npm install

  3. Create a .env file (based on the .env.example) in the root directory

  4. Add your private key in the .env file

  5. Run npm hardhat compile to compile the contracts

Astar → Astar zkEVM​

To send 1ASTR from astar(astar L1 mainnet) to zk-astar(Astar zkEVM), run the following command (Note that the --quantity flag is in wei):

npx hardhat bridge --quantity 1000000000000000000 --target-network zk-astar --network astar

Astar zkEVM → Astar​

To send 1ASTR from zk-astar(Astar zkEVM) to astar(astar L1 mainnet), run the following command (Note that the --quantity flag is in wei):

npx hardhat bridge --quantity 1000000000000000000 --target-network astar --network zk-astar

Bridge Shibuya testnet token​

We deployed OFT contracts on Shibuya and zKatana to bridge SBY (NAtive token of Shibuya) to zKatana. Please follow the steps below.

Bridging LSBY Tokens​

To facilitate token transfer, we have provided a sample repository containing a utility script:

  1. Fork the Repository

  2. Install dependencies by running npm install

  3. Create a .env file (based on the .env.example) in the root directory

  4. Add your private key in the .env file

  5. Run npm hardhat compile to compile the contracts

Shibuya EVM → zKatana​

To send 1 SBY from shibuya-testnet to zkatana-testnet, run the following command (Note that the --quantity flag is in wei):

npx hardhat astarWithFeeSend --quantity 1000000000000000000 --target-network zkatana-testnet --network astar-testnet

zKatana → Shibuya EVM​

To send 1SBY from zkatana-testnet to shibuya-testnet, run the following command (Note that the --quantity flag is in wei):

npx hardhat astarWithFeeSend --quantity 1000000000000000000 --target-network astar-testnet --network zkatana-testnet