bridge-contracts

EVM & Archethic smart contract for Archethic's Bridge

Development

In order to develop and test the contracts, you need to have some prerequisites:

• Node.js

• EVM:

  • Hardhat

• Archethic:

  • Archethic node (running in devnet mode)

Installation

npm install --prefix evm
npm install --prefix archethic

EVM contracts

There are different kind of EVM smart contracts:

• HTLC
• Liquidity pools

All the contract have their own type depending on the token used: native or ERC, because transfers/balance verification acts differently.

Audit of EVM Smart Contracts

Our EVM smart contracts have been audited by Hacken, a recognized leader in blockchain security. The full audit report is available here.

HTLC

Those contract provide the atomic swap logic.

There are few types

• Signed: contract where a signature from the Archethic's pool is required to provision the contract or to withdraw funds
• Chargeable: contract where a fee is defined and in which the pool is assigning the recipient

classDiagram
    HTLC <|-- HTLC_ERC
    HTLC <|-- HTLC_ETH
    HTLC_ERC <|-- SignedHTLC_ERC
    HTLC_ERC <|-- ChargeableHTLC_ERC
    HTLC_ETH <|-- SignedHTLC_ETH
    HTLC_ETH <|-- ChargeableHTLC_ETH

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Liquidity pools contracts

classDiagram
    Pool <|-- LP_ERC
    Pool <|-- LP_ETH

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Test SC

cd evm

For tests you can use unit tests:

npm run test

To use the pool in a local environment you can use migrations with:

npm run start-node

npm run deploy

You can use script to fill the pools

npm run fill-erc
npm run fill-eth

You can also use script to deploy chargeable HTLC contract

npx hardhat run scripts/fixture/create_erc_chargeable_htlc.js --network localhost
npx hardhat run scripts/fixture/create_eth_chargeable_htlc.js --network localhost
npx hardhat run scripts/fixture/reveal_chargeable_secret.js --network localhost

This will create two pools for ETH and ERC. It will also create a dummy token, accessible via LP_ERC.token()

Analytics

In order to run some analytics from the pools, there are two scripts to run:

• UCO pool:

This script will give swap statistics from the ERC pool using the chargeable and signed HTLC contracts.

npx hardhat run scripts/analytics/uco_bridged.js --network sepolia 

• ETH/MATIC/BSC pool:

This script will give swap statistics from the ETH pool using the chargeable and signed HTLC contracts.

npx hardhat run scripts/analytics/coin_bridged.js --network sepolia 

Archethic Smart Contracts

There is three kind of SC:

• Factory contract
• HTLC
• Pool contracts

Factory contract

This contract is a helper for DApps UI and for Pool contracts to build and verify HTLC. It also helps Pool contracts for minting new tokens.

Here is the public functions:

• get_chargeable_htlc(end_time, user_address, pool_address, secret_hash, token, amount)
  It returns the code of a HTLC for fund going from EVM chain => Archethic

  • end_time: the limit timestamp for the swap provided by EVM contracts
  • user_address: the destination address on Archethic
  • pool_address: the address of the Archethic pool to request funds
  • secret_hash: the hash of the secret generated by user
  • token: the token address to swap or "UCO"
  • amount: the amount of token the user wants to receive on Archethic

• get_signed_htlc(user_address, pool_address, token, amount)
  It returns the code of a HTLC for fund going from Archehtic => EVM chain

  • user_address: the user address on Archethic
  • pool_address: the address of the Archethic pool to request secret
  • token: the token address to swap or "UCO"
  • amount: the amount of token the user wants to receive on EVM chain

• get_protocol_fee
  It returns the protocol fees in percentage (0.3 => 0.3% = 0.003)

• get_protocol_fee_address
  It returns the address where the protocol fees are sent

HTLC

Those contracts implement the logic of atomic swap. There is two types of contracts:

• Chargeable HTLC: used when swapping from EVM chain to Archethic.
  On creation, this contract needs to request funds to a pool. To do it the transaction that contains the code should also add the pool in the recipient with the parameters end_time, amount, user_address, secret_hash.
  Actions:

  • reveal_secret(secret): reveal the secret and withdraw the fund if secret match

• Signed HTLC: use when swapping from Archethic to EVM chain.
  Public functions:

  • get_htlc_data: After provisioning, this contract will expose this function which provide the needed data to create the HTLC contract on EVM side. It returns the endtime, the secret_hash and the secret_hash_signature.
  • get_secret: After withdraw, this contract will expose this funtion which provide the needed data to withdraw the contract on EVM side. It returns the secret and the secret_signature

Pool Contracts

Those contract are responsible for creating new tokens and signing action to make a proof for EVM chain that actions has been done on Archethic.
There is one contract version for token and one for UCO.
This contract provides these actions:

• request_funds(end_time, amount, user_address, secret_hash): This actions should be triggered on the chargeable htlc creation. It ensure the HTLC contract is valid and send the requested funds to the HTLC
• request_secret_hash(htlc_genesis_address, amount, user_address, chain_id): This actions should be triggered by the user that already created a signed HTLC. In the trigger transaction, the user must add a transfer to the HTLC contract that contains the needed fund for the swap. The pool will ensure the contract is a valid one and the transfer correspond to the swap parameter, and then generate a new secret with a signature and send them to the HTCL contract
• reveal_secret(htlc_genesis_address): This actions, should be triggered by the user. The pool will send the secret to the HTLC contract so it can withdraw.
• update_pool(new_code): This action is used to update the pool code. It can be triggered only from the Master chain of the bridge

Script example

To help interaction with smart contracts, some helper scripts are available in js.
A bridge.js script can be used as entry point for any commands.
A config.js file is provided to configure the environment with endpoint, availableEvmNetworks

cd archethic

node bridge --help

Commands:
  bridge deploy_pool             Deploy a pool
  bridge deploy_factory          Deploy the factory
  bridge update_pool             Update an existing pool
  bridge init_keychain           Initialize the bridge keychain with the primary services
  bridge deploy_chargeable_htlc  Deploy a chargeable HTLC to swap from EVM to Ar chethic
  bridge deploy_signed_htlc      Deploy a signed HTLC to swap from Archethic to EVM
  bridge reveal_secret           Reveal a secret to an HTLC contract when swappi ng from EVM to Archethic
  bridge provision_htlc          Provision a signed HTLC address and request the pool the create a secret
  bridge request_secret          Request a pool to reveal the secret for a HTLC contract
Options:
  --version  Show version number                                       [boolean]
  --help     Show help                                                 [boolean]

Setup bridge contracts

Initialize the keychain if not already existing

node bridge init_keychain --help

Initialize the bridge keychain with the primary services
Options:
  --access_seed  The Keychain access seed (default in env config)       [string]
  --env          The environment config to use (default to local)       [string]

node bridge init_keychain

Create factory contract

To update factory contract the same command can be used

node bridge deploy_factory --help

Deploy the factory
Options:
  --access_seed  The Keychain access seed (default in env config)       [string]
  --env          The environment config to use (default to local)       [string]

node bridge deploy_factory

Deploy a pool

node bridge deploy_pool --help

Deploy a pool
Options:
  --token        The token to create a pool, UCO or token symbol       [string] [required]
  --access_seed  The Keychain access seed (default in env config)      [string]
  --env          The environment config to use (default to local)      [string]

node bridge deploy_pool --token UCO
node bridge deploy_pool --token aeETH

Update a pool's code

node bridge update_pool --help

Update an existing pool
Options:
  --token        The token of the pool to update, UCO or token symbol   [string] [required]
  --access_seed  the keychain access seed (default in env config)       [string]
  --env          The environment config to use (default to local)       [string]

node bridge update_pool --token UCO

Swap EVM => Archethic

First deploy HTLC contract on EVM

Deploy chargeable HTLC contract

node bridge deploy_chargeable_htlc --help

Deploy a chargeable HTLC to swap from EVM to Archethic
Options:
  --token        The token to receive on Archethic                    [string] [required]
  --seed         The seed to use for create the HTLC contract         [string] [required]
  --endtime      The end time provided by the EVM contract            [required]
  --amount       The amount to receive from the swap                  [required]
  --secret_hash  The hash of the secret                               [string] [required]
  --access_seed  the keychain access seed (default in env config)     [string]
  --env          The environment config to use (default to local)     [string]

node bridge.js deploy_chargeable_htlc --token UCO --seed htlc1 --endtime 1696934940 --amount 14.35 --secret_hash 31f7a65e315586ac198bd798b6629ce4903d0899476d5741a9f32e2e521b6a66

Withdraw on EVM

Reveal secret

bridge reveal_secret --help

Reveal a secret to an HTLC contract when swapping from EVM to Archethic
Options:
  --htlc_address  The address of the HTLC contract                  [string] [required]
  --secret        The secret allowing the contract to withdraw      [string] [required]
  --env           The environment config to use (default to local)  [string]

node bridge reveal_secret 0000b900c36b959d1b2eb52db6237e5130fe07a022e17e671656065d1b5e56bda713 toto

Archethic => EVM

Deploy signed HTLC

node bridge deploy_signed_hltc --help

Deploy a signed HTLC to swap from Archethic to EVM
Options:
  --token        The token to send to EVM                             [string] [required]
  --seed         The seed to use for create the HTLC contract         [string] [required]
  --amount       The amount to send to the swap                       [required]
  --access_seed  the keychain access seed (default in env config)     [string]
  --env          The environment config to use (default to local)     [string]

node bridge deploy_signed_htlc --token UCO --seed htlc1 --amount 5.356

Provision HTLC

node bridge provision_htlc --help

Provision a signed HTLC address and request the pool the create a secret
Options:
  --token         The token to send to the htlc contract                    [string] [required]
  --htlc_address  The genesis address of the HTLC contract to provision     [string] [required]
  --amount        The amount to send to the htlc contract                   [required]
  --chainID       The chain ID of the destination EVM blockchain
  --access_seed   the keychain access seed (default in env config)          [string]
  --env           The environment config to use (default to local)          [string]

node bridge provision_htlc --token UCO --htlc_address 0000b900c36b959d1b2eb52db6237e5130fe07a022e17e671656065d1b5e56bda713 --amount 5.356

Create EVM contract on EVM using data provided by HTLC function get_htlc_data

Request secret to the pool

node bridge request_secret --help

Request a pool to reveal the secret for a HTLC contract
Options:
  --token         The token of the pool (used to retrieve pool address)     [string] [required]
  --htlc_address  The genesis address of the HTLC contract                  [string] [required]
  --access_seed   the keychain access seed (default in env config)          [string]
  --env           The environment config to use (default to local)          [string]

node bridge.js request_secret --token UCO --htlc_address 0000b900c36b959d1b2eb52db6237e5130fe07a022e17e671656065d1b5e56bda713