I guess you won big and trying to evade paying your percentage of tax to your country which is also a part of your contribution  because of the amount of money to pay but that is not really proper. However, I think the way you can easily avoid that is through P2P. Selling to private persons is usually a way to conceal your transactions from third party to monitor what you have done and likewise government would not know except the casino is regulated by government agency directly where they can demand for winners periodically but if not that, you can sell to private people.