Unsupported Asset Retrieval Protocol

Overview

The Unsupported Asset Retrieval Protocol is designed to recover ERC20 tokens mistakenly sent to a smart contract without the required deposit function call. This protocol leverages AxiomRepl to enable users to reclaim their assets securely without compromising the integrity of the smart contract.

Background

Smart contracts typically require users to interact through specific functions to deposit assets. Direct transfers not using these functions can result in the permanent loss of assets. AxiomRepl provides a solution to recover such assets.

Example Scenario

Consider a smart contract that accepts ERC20 tokens:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.21;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

contract SomeProtocol {
    using SafeERC20 for IERC20;

    event Deposit(address indexed user, uint256 amount);
    event Withdrawal(address indexed user, uint256 amount);

    mapping(address => uint256) public balances;
    IERC20 public immutable allowedToken;

    constructor(IERC20 _allowedToken) {
        allowedToken = _allowedToken;
    }

    function deposit(uint256 amount) external {
        allowedToken.safeTransferFrom(msg.sender, address(this), amount);
        balances[msg.sender] += amount;
        emit Deposit(msg.sender, amount);
    }

    function withdrawal(uint256 amount) external {
        require(balances[msg.sender] >= amount, "insufficient balance");
        balances[msg.sender] -= amount;
        allowedToken.safeTransfer(msg.sender, amount);
        emit Withdrawal(msg.sender, amount);
    }
}

If a user sends tokens directly to the contract's address, bypassing the deposit() function, those tokens would be stuck. AxiomRepl allows users to prove the occurrence of such a transfer and retrieve their tokens.

Protocol Mechanics

For the retrieval of supported tokens, the process involves staking, a challenge period, and the possibility of zero-knowledge proofs to ensure honesty and security. This complex scenario is beyond the scope of the current demonstration.

Repository Structure

AxiomRepl: View on AxiomRepl
Smart Contract Code: View on GitHub
Example Transaction: View on Goerli Etherscan

Demonstration Guide

Prerequisites

Ensure you have Node.js and Yarn installed.

Steps

1. Transfer Unsupported ERC20 Token

Simulate an unsupported deposit to the protocol:

ERC20 Token Address: 0xbaE940De6ef7D897Ad76bA8bfa7f93939F82E976
Protocol Address: 0x430faeE7cF005d848dE5BD4F6c385D552430aE04
Example TX: 0x674a5882e6191482b80c625a805736c7ec6c85d0b909a7ba8308c8a5449c838a

2. Submit zk Proof

Prove the unsupported transfer to initiate the refund:

Start the web server:
```
yarn dev
```
Visit localhost:3000 and input the transaction details.
Click "Build and Send Query (on Goerli)".
Proof TX: 0xa4d7df3613d761c36efad9c685d5ca565a25366a1748e48bf3e3ef3e9864dd1b

3. AxiomRepl Callback

AxiomRepl will confirm the proof and initiate a callback:

Axiom Explorer Query: View Query
Etherscan TX: 0xd3ab31ddad9991c7bf37b8f0546a81675903757ab8a5217eea3a12a03e2d9f7c

4. Initiate UnsupportedTokenWithdrawal

Users can now withdraw their unsupported tokens:

Withdrawal TX: 0x904bd694c92330f43490914c2ebef26b25fdf117dc93399e2658a72dc5b88d7f

Conclusion

This protocol provides a secure method for users to reclaim ERC20 tokens sent in error. The demonstration above guides you through the process to safely retrieve your assets.

jayden-sudo/UnsupportedAssetRefund