Hashport Contracts

This repository contains the smart contracts for the Hedera <-> EVM Bridge.

• Overview
• Contract Addresses & ABI
• Development
  • Prerequisites
  • Compilation
  • Scripts
    • Router deployment
    • Wrapped token Deployment
  • Tests
    • Unit Tests
    • Coverage
• Gas Usages

Overview

Core functionality of Hedera <-> EVM Bridge.

In essence, the business logic behind the smart contracts is to allow the possibility to transfer a token from one network to another. Of course, you cannot directly transfer the token to the network, so in order this to be possible it has to have a representation of that token, a so-called wrapped version of the original native token. In our terms, a wrapped token on a given network is a representation of a native token on another network. A native token can have wrapped representations on more than one EVM network.

Users operate with the following functionality:

• lock - lock a specific amount of native tokens, specifying the receiver and target network.
• unlock - unlock a previously locked amount of native tokens by providing an array of signatures. Signatures are verified that they are signed by the members.
• mint - mint a specific amount of wrapped tokens by providing an array of signatures, verified that they are signed by the members.
• burn - burn a specific amount of wrapped tokens.

EVM native tokens have to be explicitly added as supported native tokens in the smart contracts. Each native token has a service fee percentage, which will be left for the smart contract members upon locking/unlocking native tokens. Members are entities, which will serve as governance whenever a user wants to get wrapped tokens from native tokens and vice versa. Fees for native tokens accumulate equally between members. Members need to explicitly claim (transfer) their accumulated fees for a given native token.

You can read more here.

Smart Contracts use EIP-2535.

Contract Addresses & ABI

Mainnet deployed contract addresses

ABIs

Facet ABIs are available under ./abi directory.

Development

Prerequisites

node.js >= v14.17.0

hardhat - framework used for the development and testing of the contracts

After cloning, run:

cd hedera-eth-bridge-contracts
npm install

Compilation

Before you deploy the contracts, you will need to compile them using:

npx hardhat compile

Scripts

Before running any npx hardhat scripts, you need to set the following environment variables in hardhat config or export them:

export ALCHEMY_PROJECT_ID=<PROJECT ID of ALCHEMY>
export DEPLOYER_PRIVATE_KEY=<private key to use for deployments for the specified network>

Router deployment

• Deploys all the facets
• Deploys the Router Diamond with all the facets as diamond cuts
• Initializes GovernanceFacet with the provided list of members, governance percentage, and governance precision
• Initializes RouterFacet
• Initializes FeeCalculatorFacet with the provided fee precision.
• As a second step - the script will update the router as follows:
  • Add PaymentFacet
  • Add ERC721PortalFacet
  • Replace GovernanceFacet with GovernanceV2Facet

npx hardhat deploy-router \
    --network <network name> \
    --owner <owner address> \
    --governance-percentage <governance percentage> \
    --governance-precision <governance precision> \
    --fee-calculator-precision <fee calculator precision> \
    --members <list of members, split by `,`> \
    --members-admins <list of members admins, split by `,`>

Wrapped ERC-20 token deployment through Router

Deploys a wrapped token through Router for a corresponding token on another chain:

npx hardhat deploy-router-wrapped-token \
    --network <network name> \
    --router <address of the router diamond contract> \
    --source <id of the source chain, to which the native token is deployed> \
    --native <the unique identifier of the native token> \
    --name <name of the wrapped token> \
    --symbol <symbol of the wrapped token> \
    --decimals <decimals of the wrapped token>

Wrapped ERC-20 token deployment

Deploys an instance of a Wrapped Token contract, used for testing purposes.

npx hardhat deploy-wrapped-token \
    --network <network name> \
    --name <name of the token> \
    --symbol <symbol of the token> \
    --decimals <decimals of the token>

Wrapped ERC-721 token deployment and Transfer Ownership to Diamond Router

Deploys a wrapped ERC-721 and transfers ownership to Diamond Router

npx hardhat deploy-wrapped-erc721-transfer-ownership \
    --network <network name> \
    --router <address of the router diamond contract> \
    --name <name of the ERC-721> \
    --symbol <symbol of the ERC-721>

Wrapped ERC-721Pausable token deployment and Transfer Ownership to Diamond Router

Deploys a wrapped ERC-721Pausable and transfers ownership to Diamond Router

npx hardhat deploy-wrapped-erc721-pausable-transfer-ownership \
    --network <network name> \
    --router <address of the router diamond contract> \
    --name <name of the ERC-721> \
    --symbol <symbol of the ERC-721>

Token deployment

Deploys an instance of a Token contract, used for testing purposes.

npx hardhat deploy-token \
    --network <network name> \
    --name <name of the token> \
    --symbol <symbol of the token> \
    --decimals <decimals of the token>

Update Native Token to Router

Updates a native token to the Router contract:

npx hardhat update-native-token \
    --network <network name> \
    --router <address of the router diamond contract> \
    --native-token <address of the native token> \
    --fee-percentage <fee percetange for the given token> \
    --status <true|false (default true)>

Upgrade diamond to support ERC-721

Upgrades the diamond to support ERC-721:

npx hardhat upgrade-erc721-support \
    --network <network name> \
    --router <address of the Router Diamond contract>

Set Payment Token

Requires Router Diamond Contract to be upgraded with PaymentFacet support

npx hardhat set-payment-token \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --payment-token <address of ERC-20 payment token contract> \
    --status <true|false (default true)>

Set ERC-721 Payment

Requires Router Diamond Contract to be upgraded with ERC721PortalFacet & PaymentFacet support

npx hardhat set-erc721-payment \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --erc721 <address of the ERC-721 contract> \
    --payment-token <address of the ERC-20 payment token contract> \
    --fee <required Payment Token fee upon burnERC721 wrapped transfers>

Mint Wrapped ERC-721

Requires Router Diamond Contract to support ERC721PortalFacet Mints Wrapped ERC-721 tokenID to the corresponding network

npx hardhat mint-erc721 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --source-chain-id <The chain id of the source chain> \
    --target-chain-id <The chain id of the target chain> \
    --transaction-id <The target transaction id> \
    --wrapped-asset <The address of the wrapped ERC-721 token> \
    --token-id <The target token ID to be minted> \
    --metadata <The token ID metadata> \
    --receiver <The address of the receiver> \
    --signatures <An array of signatures, split by `,`>

Burn Wrapped ERC-721

Burns Wrapped ERC-721 tokenId to the corresponding network

npx hardhat burn-erc721 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --target-chain-id <The chain id of the target chain> \
    --wrapped-asset <The address of the wrapped ERC-721 token> \
    --token-id <The token id to be burned> \
    --receiver <The address/AccountID of the receiver>

Mint Wrapped ERC-20

Mints Wrapped ERC-20 amount to the corresponding network

npx hardhat mint-erc20 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --source-chain-id <The chain id of the source chain> \
    --target-chain-id <The chain id of the target chain> \
    --transaction-id <The target transaction id> \
    --wrapped-asset <The address of the wrapped ERC-20 token> \
    --receiver <The address of the receiver> \
    --amount <The amount to be minted> \
    --signatures <An array of signatures, split by `,`>

Burn Wrapped ERC-20

Approves & Burns Wrapped ERC-20 amount to the corresponding network

npx hardhat burn-erc20 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --target-chain-id <The chain id of the target chain> \
    --wrapped-asset <The address of the wrapped ERC-20 token> \
    --amount <The target amount> \
    --receiver <The address/AccountID of the receiver on the target network>

Lock Native ERC-20

Locks Native ERC-20 amount to the corresponding network

npx hardhat lock-erc20 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --target-chain-id <The chain id of the target chain> \
    --native-asset <The address of the native ERC-20 token> \
    --amount <The amount to be locked> \
    --receiver <The address/AccountID of the receiver>

Unlock Native ERC-20

Unlocks Native ERC-20 amount to the corresponding network

npx hardhat unlock-erc20 \
    --network <network name> \
    --router <address of the Router Diamond contract> \
    --source-chain-id <The chain id of the source chain> \
    --target-chain-id <The chain id of the target chain> \
    --transaction-id <The target transaction id> \
    --native-asset <The address of the native ERC-20 token> \
    --receiver <The address of the receiver> \
    --amount <The amount to be minted> \
    --signatures <An array of signatures, split by `,`>

Transfer Ownership of a Contract

Transfers Ownership of a Contract to specified new owner.

npx hardhat transfer-ownership \
    --network <network name> \
    --contract <address of the contract> \
    --new-owner <address of the new owner>

Tests

Unit Tests

npx hardhat test

Coverage

npx hardhat coverage

Gas Usages

• lockWithPermit

  • Whole balance ~ 70 000 gas
  • ~ 82 000 gas

• unlock

  • 3 signatures ~ 118 132 gas
  • ~ 8500 gas per signature

• mint

  • 3 signatures ~ 140 223 gas
  • ~ 8500 gas per signature

• burnWithPermit

  • Whole balance ~ 45 127 gas
  • ~70 322 gas

• updateMember

  • Addition
    • 3 tokens ~ 180 000 gas (if fees for tokens have been accrued at least once)
    • ~ 35 000 gas per Token
  • Removal
    • 3 tokens ~ 140 000 gas
    • ~ 37 000 gas per Token

NB! Running Unit Tests includes a gas reporter, providing metrics for method calls and deployments.