NativeToken

Arthera provides a native precompiled contract to interact with the AA coin through an ERC20 interface. One of the main benefits of this precompile is that it removes the necessity of having a wrapped representation of the protocol token as an ERC-20 smart contract, such as WETH on Ethereum. Furthermore, it prevents having multiple wrapped representations of the same protocol token. Consequently, DApps that need to interact with the protocol token via an ERC-20 interface can do so without needing a separate smart contract.

Available on all Arthera networks at address: 0x000000000000000000000000000000000000aA09

The AA ERC20 interface respects OpenZeppelin's IERC20Metadata.sol interface that extends IERC20.sol with the name(), symbol() and decimals() functions.

More specifically, the AA ERC20 interface is defined as follows:

name()

Read-only function that returns the value Arthera

symbol()

Read-only function that returns the value AA

decimals()

Read-only function that returns the value 18

totalSupply()

Read-only function that returns the total supply of AA tokens in existence.

balanceOf()

Read-only function that returns the amount of AA tokens owned by account.

Method parameters:

• address account the account to get the balance of

allowance()

Read-only function that checks and returns the amount of AA that a spender is allowed to spend on behalf of the owner.

Method parameters:

• address owner the account that owns the AA
• address spender the account that can spend the AA

transfer()

Transfers the given amount of AA to a specified address and returns true if the transfer was successful

Method parameters:

• address to the account to transfer the AA to
• uint256 amount the amount of AA to transfer

Emits

• event Transfer(address indexed from, address indexed to, uint256 value)

approve()

Approves the provided address to spend a specified amount of AA on behalf of the caller. Returns true if successful.

Method parameters:

• msg.sender the account that owns the AA
• address spender the account that can spend the AA
• uint256 amount the maximum amount of AA the spender can spend on behalf of msg.sender

Emits

• event Approve(address indexed from, address indexed to, uint256 value)

transferFrom()

Transfers the given amount of AA from a specified address to another address and returns true if the transfer was successful. The msg.sender must be approved to spend AA on behalf of the from account.

Method parameters:

• address from the account to transfer the AA from
• address to the account to transfer the AA to
• uint256 amount the amount of AA to transfer

The ERC-20 standard does not specify the implications of multiple calls to approve(). Changing an allowance with this function numerous times enables a possible attack vector. To avoid incorrect or unintended transaction ordering, you can first reduce the spender allowance to 0 and then set the desired allowance afterward. For more details on the attack vector, you can check out ERC-20 API: An Attack Vector on Approve/TransferFrom Methods overview)