// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)pragmasolidity ^0.8.20;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/eventApproval(addressindexed owner, addressindexed spender, uint256 value);
/**
* @dev Returns the value of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the value of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (uint256);
/**
* @dev Moves a `value` amount of tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransfer(address to, uint256 value) externalreturns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/functionallowance(address owner, address spender) externalviewreturns (uint256);
/**
* @dev Sets a `value` amount of tokens as the allowance of `spender` over the
* caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/functionapprove(address spender, uint256 value) externalreturns (bool);
/**
* @dev Moves a `value` amount of tokens from `from` to `to` using the
* allowance mechanism. `value` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/functiontransferFrom(addressfrom, address to, uint256 value) externalreturns (bool);
}
Contract Source Code
File 2 of 2: TokenBurner.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.0;import"@openzeppelin/contracts/token/ERC20/IERC20.sol";
contractTokenBurner{
IERC20 public token;
eventTokensBurned(addressindexed user, uint256 amount, string mintlayerAddress);
constructor() {
token = IERC20(0x059956483753947536204e89bfaD909E1a434Cc6);
}
functionisValidMintlayerAddress(stringmemory _mintlayerAddress) publicpurereturns (bool) {
bytesmemory b =bytes(_mintlayerAddress);
if (b.length<42|| b.length>46) {
returnfalse;
}
// Checking if it starts with "mtc1q"if (b[0] !='m'|| b[1] !='t'|| b[2] !='c'|| b[3] !='1') {
returnfalse;
}
returntrue;
}
functionburnTokens(uint256 _amount, stringmemory _mintlayerAddress) public{
require(_amount >0, "Amount must be greater than 0");
require(isValidMintlayerAddress(_mintlayerAddress), "Invalid Mintlayer address");
// Transferring tokens to the contractrequire(token.transferFrom(msg.sender, address(this), _amount), "Transfer failed");
// Emitting eventemit TokensBurned(msg.sender, _amount, _mintlayerAddress);
}
}