message: chore(issuer): Possible casino attacks
diff: @@ -80,6 +80,8 @@ contract Issuer is Initializable, OwnableUpgradeable, UUPSUpgradeable {
  }
  function requestCertificationFor(bytes memory _data, address _owner) public returns (uint256) {
  + require(_owner != address(0), "Owner cannot be 0x0");
  +
  uint256 id = ++_latestCertificationRequestId;
  _certificationRequests[id] = CertificationRequest({
  @@ -98,6 +100,10 @@ contract Issuer is Initializable, OwnableUpgradeable, UUPSUpgradeable {
  function requestCertificationForBatch(bytes[] memory _data, address[] memory _owners) public returns (uint256[] memory) {
  uint256[] memory requestIds = new uint256[](_data.length);
  + for (uint256 i = 0; i < _data.length; i++) {
  + require(_owners[i] != address(0), "Owner cannot be 0x0");
  + }
  +
  for (uint256 i = 0; i < _data.length; i++) {
  uint256 id = i + _latestCertificationRequestId + 1;
  