Swap ERC7984 to ERC20
This example demonstrates how to swap between a confidential token - the ERC7984 and the ERC20 tokens using OpenZeppelin's smart contract library powered by ZAMA's FHEVM.
// SPDX-License-Identifier: BSD-3-Clause-Clear
pragma solidity ^0.8.24;
import {FHE, externalEuint64, euint64} from "@fhevm/solidity/lib/FHE.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {IERC7984} from "@openzeppelin/confidential-contracts/interfaces/IERC7984.sol";
contract SwapERC7984ToERC20 {
error SwapERC7984ToERC20InvalidGatewayRequest(uint256 requestId);
mapping(uint256 requestId => address) private _receivers;
IERC7984 private _fromToken;
IERC20 private _toToken;
constructor(IERC7984 fromToken, IERC20 toToken) {
_fromToken = fromToken;
_toToken = toToken;
}
function SwapERC7984ToERC20(externalEuint64 encryptedInput, bytes memory inputProof) public {
euint64 amount = FHE.fromExternal(encryptedInput, inputProof);
FHE.allowTransient(amount, address(_fromToken));
euint64 amountTransferred = _fromToken.confidentialTransferFrom(msg.sender, address(this), amount);
bytes32[] memory cts = new bytes32[](1);
cts[0] = euint64.unwrap(amountTransferred);
uint256 requestID = FHE.requestDecryption(cts, this.finalizeSwap.selector);
// register who is getting the tokens
_receivers[requestID] = msg.sender;
}
function finalizeSwap(uint256 requestID, uint64 amount, bytes[] memory signatures) public virtual {
FHE.checkSignatures(requestID, signatures);
address to = _receivers[requestID];
require(to != address(0), SwapERC7984ToERC20InvalidGatewayRequest(requestID));
delete _receivers[requestID];
if (amount != 0) {
SafeERC20.safeTransfer(_toToken, to, amount);
}
}
}Last updated