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MagicalInternetMoney_v0.8.2_Sepolia_0x5B84e1706CD6Ae0d79486Dd6F30503B4330742E1.sol
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MagicalInternetMoney_v0.8.2_Sepolia_0x5B84e1706CD6Ae0d79486Dd6F30503B4330742E1.sol
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/**
*Submitted for verification at Etherscan.io on 2024-01-16
*/
pragma solidity ^0.8.19;
// ----------------------------------------------------------------------------
// MagicalInternetMoney v0.8.2 - Experiments in ERC-5564: Stealth Addresses
//
// Deployed to Sepolia 0x5B84e1706CD6Ae0d79486Dd6F30503B4330742E1
//
// https://github.com/bokkypoobah/MagicalInternetMoney
//
// SPDX-License-Identifier: MIT
//
// Enjoy. (c) BokkyPooBah / Bok Consulting Pty Ltd 2024
// ----------------------------------------------------------------------------
// import "hardhat/console.sol";
function onePlus(uint x) pure returns (uint) {
unchecked { return 1 + x; }
}
/// @notice Interface for announcing when something is sent to a stealth address.
interface IERC5564Announcer {
/// @dev Emitted when sending something to a stealth address.
/// @dev See the `announce` method for documentation on the parameters.
event Announcement(uint256 indexed schemeId, address indexed stealthAddress, address indexed caller, bytes ephemeralPubKey, bytes metadata);
/// @dev Called by integrators to emit an `Announcement` event.
/// @param schemeId The integer specifying the applied stealth address scheme.
/// @param stealthAddress The computed stealth address for the recipient.
/// @param ephemeralPubKey Ephemeral public key used by the sender.
/// @param metadata An arbitrary field MUST include the view tag in the first byte.
/// Besides the view tag, the metadata can be used by the senders however they like,
/// but the below guidelines are recommended:
/// The first byte of the metadata MUST be the view tag.
/// - When sending/interacting with the native token of the blockchain (cf. ETH), the metadata SHOULD be structured as follows:
/// - Byte 1 MUST be the view tag, as specified above.
/// - Bytes 2-5 are `0xeeeeeeee`
/// - Bytes 6-25 are the address 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE.
/// - Bytes 26-57 are the amount of ETH being sent.
/// - When interacting with ERC-20/ERC-721/etc. tokens, the metadata SHOULD be structured as follows:
/// - Byte 1 MUST be the view tag, as specified above.
/// - Bytes 2-5 are a function identifier. When a function selector (e.g.
/// the first (left, high-order in big-endian) four bytes of the Keccak-256
/// hash of the signature of the function, like Solidity and Vyper use) is
/// available, it MUST be used.
/// - Bytes 6-25 are the token contract address.
/// - Bytes 26-57 are the amount of tokens being sent/interacted with for fungible tokens, or
/// the token ID for non-fungible tokens.
function announce(uint256 schemeId, address stealthAddress, bytes memory ephemeralPubKey, bytes memory metadata) external;
}
interface ITransferFrom {
// ERC-20 function transferFrom(address from, address to, uint tokens) external returns (bool success);
// ERC-721 function transferFrom(address from, address to, uint256 tokenId) external;
function transferFrom(address from, address to, uint256 tokensOrTokenId) external;
}
interface IERC20Allowance {
function allowance(address tokenOwner, address spender) external view returns (uint remaining);
}
interface IERC721OwnerOf {
function ownerOf(uint256 tokenId) external view returns (address owner);
}
struct TokenInfo {
bool isERC721;
address token;
uint value;
}
/// @notice Magical Internet Money things
contract MagicalInternetMoney {
// 0x23b872dd transferFrom(address,address,uint256)
bytes4 private constant TRANSFERFROM_SELECTOR = 0x23b872dd;
IERC5564Announcer announcer;
error NothingToTransfer();
error TransferFailure();
error NotERC721TokenOwner();
error InsufficientERC20Allowance();
constructor(address payable _announcer) {
announcer = IERC5564Announcer(_announcer);
}
/// @dev Transfer ETH and announce
/// @param schemeId The integer specifying the applied stealth address scheme.
/// @param recipient The computed stealth address for the recipient.
/// @param ephemeralPubKey Ephemeral public key used by the sender.
/// @param viewTag The view tag derived from the shared secret.
function transferEthAndAnnounce(uint256 schemeId, address recipient, bytes memory ephemeralPubKey, uint8 viewTag) external payable {
if (msg.value == 0) {
revert NothingToTransfer();
}
bytes memory metadata = new bytes(57);
uint i;
uint j;
metadata[j++] = bytes1(viewTag);
for (; i < 24; i = onePlus(i)) {
metadata[j++] = 0xee;
}
bytes32 msgValueInBytes = bytes32(msg.value);
for (i = 0; i < 32; i = onePlus(i)) {
metadata[j++] = msgValueInBytes[i];
}
(bool sent, ) = recipient.call{value: msg.value}("");
if (!sent) {
revert TransferFailure();
}
announcer.announce(schemeId, recipient, ephemeralPubKey, metadata);
}
/// @dev Transfer ETH/ERC-20/ERC-721 and announce
/// @param schemeId The integer specifying the applied stealth address scheme.
/// @param recipient The computed stealth address for the recipient.
/// @param ephemeralPubKey Ephemeral public key used by the sender.
/// @param viewTag The view tag derived from the shared secret.
/// @param tokenInfo Array of [isERC721, tokenAddress, tokenValue] to transfer
function transferAndAnnounce(uint256 schemeId, address recipient, bytes memory ephemeralPubKey, uint8 viewTag, TokenInfo[] calldata tokenInfo) external payable {
if (tokenInfo.length == 0 && msg.value == 0) {
revert NothingToTransfer();
}
bytes memory metadata = new bytes(1 + (56 * (tokenInfo.length + (msg.value > 0 ? 1 : 0))));
uint i;
uint j;
metadata[j++] = bytes1(viewTag);
if (msg.value > 0) {
for (; i < 24; i = onePlus(i)) {
metadata[j++] = 0xee;
}
bytes32 msgValueInBytes = bytes32(msg.value);
for (i = 0; i < 32; i = onePlus(i)) {
metadata[j++] = msgValueInBytes[i];
}
(bool sent, ) = recipient.call{value: msg.value}("");
if (!sent) {
revert TransferFailure();
}
}
for (i = 0; i < tokenInfo.length; i = onePlus(i)) {
bytes memory selectorAndTokenContractInBytes = abi.encodePacked(TRANSFERFROM_SELECTOR, tokenInfo[i].token);
uint k;
for (k = 0; k < 24; k = onePlus(k)) {
metadata[j++] = selectorAndTokenContractInBytes[k];
}
bytes32 valueInBytes = bytes32(tokenInfo[i].value);
for (k = 0; k < 32; k = onePlus(k)) {
metadata[j++] = valueInBytes[k];
}
// msg.sender can only transfer their own ERC-721 tokens
if (tokenInfo[i].isERC721) {
address owner = IERC721OwnerOf(tokenInfo[i].token).ownerOf(tokenInfo[i].value);
if (owner != msg.sender) {
revert NotERC721TokenOwner();
}
// Check ERC-20 allowance to prevent the ERC-721 ownership check above being bypassed
} else {
uint allowance = IERC20Allowance(tokenInfo[i].token).allowance(msg.sender, address(this));
if (allowance < tokenInfo[i].value) {
revert InsufficientERC20Allowance();
}
}
ITransferFrom(tokenInfo[i].token).transferFrom(msg.sender, recipient, tokenInfo[i].value);
}
announcer.announce(schemeId, recipient, ephemeralPubKey, metadata);
}
}