ERC20 Permit

This project is an implementation of an ERC2612 enabled ERC20 token.

It allows to use signatures calculated off-chain to increase allowances using permit. The call to permit doesn't need to be done by the holder, so this contract allows the implementation of "gas-less" tokens, or the replacement of approve transactions by methods that call permit and transferFrom atomically.

Most of the code in this repository was written by Georgios Konstantopoulos.

How to Use

ERC20Permit is an ERC20 contract. You can just inherit it and you are done from the smart contracts point of view.

contract MyContract is ERC20Permit {

    constructor (string memory _name, string memory _symbol) public ERC20Permit(_name, _symbol) {...}

    ...
}

The utils/signatures.ts file contains useful functions to compute the DOMAIN_SEPARATOR, digest and signature from typescript.

Further reading

This article explains in detail how to use the code in this repository.