The Great Key Leak of 2020 was a huge key leak that occured at the beginning of May 2020. This event forced badspot to disable key verification and make the game steam only.
Keys were stolen using the special RCE program which was hijacking all keys from people who joined a certain server. It is presumed that the mastermind behind the attack is a player named dexxay who with help of aebaadcode and Caden100 planted the RCE a few months before the actual leak.