Passage

Passage is responsible for ETH and ERC-20 tokens entering Signet.

The Passage contract:

Accepts ETH and ERC20 deposits, emitting Enter and EnterToken events for the Signet Node
Maintains the list of assets allowed to enter the Rollup.

Logic

The Passage contract facilitates asset transfers between Ethereum and Signet. ETH deposits trigger Enter events, prompting the Signet Node to mint ETH for the recipient. Similarly, ERC20 deposits trigger EnterToken events, leading to the minting of corresponding tokens on Signet.

A multisig account, tokenAdmin, manages the contract’s key functions. The administrator maintains an allowlist that prevents most ERC20 tokens on Ethereum from entering Signet.

Invariants

erc20.totalSupply() on the Rollup <= erc20.balanceOf(passage) on the Host chain
ETH total supply on the Rollup <= address(passage).balance on the Host chain
address(rollupPassage).balance == 0 at the end of each Rollup block

More information

For further details on tokenAdmin, see Permissioned Roles.
For contract source code, see contracts in the passage/ folder.