# IERC20Permit







*Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in https://eips.ethereum.org/EIPS/eip-2612[EIP-2612]. Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't need to send a transaction, and thus is not required to hold Ether at all.*

## Methods

### DOMAIN_SEPARATOR

```solidity
function DOMAIN_SEPARATOR() external view returns (bytes32)
```



*Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.*


#### Returns

| Name | Type | Description |
|---|---|---|
| _0 | bytes32 | undefined |

### nonces

```solidity
function nonces(address owner) external view returns (uint256)
```



*Returns the current nonce for `owner`. This value must be included whenever a signature is generated for {permit}. Every successful call to {permit} increases ``owner``'s nonce by one. This prevents a signature from being used multiple times.*

#### Parameters

| Name | Type | Description |
|---|---|---|
| owner | address | undefined |

#### Returns

| Name | Type | Description |
|---|---|---|
| _0 | uint256 | undefined |

### permit

```solidity
function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external nonpayable
```



*Sets `value` as the allowance of `spender` over ``owner``'s tokens, given ``owner``'s signed approval. IMPORTANT: The same issues {IERC20-approve} has related to transaction ordering also apply here. Emits an {Approval} event. Requirements: - `spender` cannot be the zero address. - `deadline` must be a timestamp in the future. - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner` over the EIP712-formatted function arguments. - the signature must use ``owner``'s current nonce (see {nonces}). For more information on the signature format, see the https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP section].*

#### Parameters

| Name | Type | Description |
|---|---|---|
| owner | address | undefined |
| spender | address | undefined |
| value | uint256 | undefined |
| deadline | uint256 | undefined |
| v | uint8 | undefined |
| r | bytes32 | undefined |
| s | bytes32 | undefined |