Custody

What is Custody?

In our project, we allow user to connect their Metamask wallet onto our platform, providing them a more secure environment for their assets. Users can then deposit funds onto the custody wallet. This deposit to the custody wallet will then open a state channel off-chain. By following nitro protocols on the state channel, we can then have instant finality to user balances after each transaction. This allows the user to have locked balances and make partial/full withdrawals from the custody wallet, back to the Metamask.

Smart Contracts

IVault

IVault is the interface to implement custody

Contents

• Functions
• Events

Functions

getLastId

📋    Get last ledger id (deposits and withdrawals id).

Declaration

  function getLastId(
  ) external returns (uint256)

Returns:

Type	Description
uint256	Ledger id.

Events

Deposited

📋    Deposited event

Params:

Param	Type	Indexed	Description
id	uint256	✅	Ledger id
account	address	✅	Account address
asset	address	✅	Asset address to deposit
amount	uint256		Quantity of assets to be deposited

Withdrawn

📋    Withdrawn event

Params:

Param	Type	Indexed	Description
id	uint256	✅	Ledger id
account	address	✅	Account address
asset	address	✅	Asset address to deposit
amount	uint256		Quantity of assets to be deposited

SimpleVault

Custody smart contracts aim to provide a secure trading environment by holding the assets on the erc20 chain so that the user and broker can freely trade off-chain.

Contents

• Globals
• Modifiers
• Functions

Globals

Var	Type	Description
BROKER_ROLE	bytes32	Broker role identifier value
WITHDRAW_TYPE	bytes32	Withdrawal type identifier value

Modifiers

onlyValidMovingFundParams

📋    Modifier to check information required for deposits and withdrawals.

Declaration

  modifier onlyValidMovingFundParams(
    address account
  )

Args:

Arg	Type	Description
account	address	Account address to check

Functions

initialize

📋    The constructor function sets the contract name and broker's address.

Declaration

  function initialize(
    string name_,
    address broker_
  ) public initializer

Modifiers:

Modifier
initializer

Args:

Arg	Type	Description
name_	string	Contract name
broker_	address	Broker name

name

📋    Get contract name.

Declaration

  function name(
  ) public returns (string)

Returns:

Type	Description
string	Contract name

changeBroker

📋    Change broker address who signed the withdrawal signature.

Declaration

  function changeBroker(
    address newBroker
  ) external onlyRole

Modifiers:

Modifier
onlyRole

Args:

Arg	Type	Description
newBroker	address	Broker address

getLastId

📋    Get last ledger id (deposits and withdrawals id).

Declaration

  function getLastId(
  ) external returns (uint256)

Returns:

Type	Description
uint256	Ledger id.

deposit

📋    Deposit the asset with given amount into custody

Declaration

  function deposit(
    address asset,
    uint256 amount
  ) public returns (bool)

Args:

Arg	Type	Description
asset	address	Asset address to deposit
amount	uint256	Quantity of assets to be deposited

Returns:

Type	Description
bool	Return 'true' when deposited

_deposit

📋    Internal deposit process and increment ledger id

Declaration

  function _deposit(
    address account,
    address asset,
    uint256 amount
  ) internal onlyValidMovingFundParams returns (bool)

Modifiers:

Modifier
onlyValidMovingFundParams

Args:

Arg	Type	Description
account	address	Account address
asset	address	Asset address to deposit
amount	uint256	Quantity of assets to be deposited

Returns:

Type	Description
bool	Return 'true' when deposited

withdraw

📋    Withdraw the asset with given payload to the caller

Declaration

  function withdraw(
    bytes payload,
    bytes signature
  ) public returns (bool)

Args:

Arg	Type	Description
payload	bytes	Withdrawal payload consists of rid (unique identifier id), deadline, destination, and the list of withdrawal asset and amount
signature	bytes	Broker signature

Returns:

Type	Description
bool	Return 'true' when withdrawn

_withdraw

📋    Internal withdraw process and increment ledger id

Declaration

  function _withdraw(
    address account,
    bytes payload,
    bytes signature
  ) internal onlyValidMovingFundParams returns (bool)

Modifiers:

Modifier
onlyValidMovingFundParams

Args:

Arg	Type	Description
account	address	Account address
payload	bytes	Withdrawal payload consists of rid (unique identifier id), deadline, destination, and the list of withdrawal asset and amount
signature	bytes	Broker signature

Returns:

Type	Description
bool	Return 'true' when withdrawn

_transferAssetFrom

📋    Transfers the given amount of this AssetHolders's asset type from a supplied ethereum address.

Declaration

  function _transferAssetFrom(
    address asset,
    address from,
    uint256 amount
  ) internal

Args:

Arg	Type	Description
asset	address	Asset address to transfer
from	address	Ethereum address to be credited
amount	uint256	Quantity of assets to be transferred

_transferAssetTo

📋    Transfers the given amount of this AssetHolders's asset type to a supplied ethereum address.

Declaration

  function _transferAssetTo(
    address asset,
    address destination,
    uint256 amount
  ) internal

Args:

Arg	Type	Description
asset	address	Asset address to transfer
destination	address	Ethereum address to be credited
amount	uint256	Quantity of assets to be transferred