@keep-network/tbtc-v2-optimism v1.0.2

:toc: macro

= Threshold cross-chain - Optimism

This package brings Bitcoin to Ethereum L2 Optimism. For more details please see link:https://github.com/keep-network/tbtc-v2/blob/main/docs/rfc/rfc-8.adoc[RFC 8: Cross-chain Tokenized Threshold BTC]

== How it works?

+----------------------------+         +---------------------------------------------------------------------------+
|          Ethereum          |         |                                Optimism                                   |
|                            |         |                                                                           |
|  +----------------------+  |         |  +----------------------+  +-------------------------+  +--------------+  |
|  | Wormhole TokenBridge |--|---------|--| Wormhole TokenBridge |--| OptimismWormholeGateway |--| OptimismTBTC |  |
|  +----------------------+  |         |  +----------------------+  +-------------------------+  +--------------+  |
|                            |         |                                                                           |
+----------------------------+         +---------------------------------------------------------------------------+

• OptimismTBTC canonical tBTC token on Optimism with a minting authority delegated to OptimismWormholeGateway.
• OptimismWormholeGateway is a smart contract wrapping and unwrapping Wormhole-specific tBTC representation into the canonical OptimismTBTC token.

=== Updating Wormhole Gateway mapping

The deployment scripts are responsible for managing updates of the tBTC gateway addresses across various chains. These addresses are stored in the external/ directory for a specific network, such as optimismGoerli/ArbitrumWormholeGateway.json. It is important to note that these addresses should remain constant for the mainnet network. However, there may be instances where a new version of a cross-chain module is deployed to the testing network, which would require a manual update of the corresponding address.

=== Deploy contracts

To deploy all contracts on the given network, please run:

yarn deploy --network <network>

Supported networks:

• hardhat - for local development
• optimismGoerli - L2 testing network
• optimism - L2 mainnet

Currently, this module does not deploy any contracts on L1. All the existing Wormhole contract addresses that are used in this module are stored under external/<network> dir.

If contracts haven't been built yet or changes occurred, deploy task will build the contracts before running the deployment script. This command produces an export.json file containing contract deployment info. Note that for the chains other than hardhat the following environment variables are needed:

• L2_CHAIN_API_URL - URL to access blockchain services, e.g. https://opt-goerli.g.alchemy.com/v2/<alchemy_api_key>
• L2_ACCOUNTS_PRIVATE_KEYS - Private keys for the deployer and council <0xOwnerPrivKey,0xCouncilPrivKey>
• OPTIMISM_ETHERSCAN_API_KEY - Optimism Etherscan API key