RensenWare is a ransomware trojan for Microsoft Windows released in April 2017. It was created by Park Shinjo as a prank on his friends, however, the RensenWare managed to spread throughout the world in a few days.
When RensenWare finishes encrypting a computer's files, it will display a ransom note and official artwork of Captain Minamitsu Murasa from Touhou 12: Undefined Fantastic Object.
Similar to other ransomware, RensenWare will encrypt almost every file in the victim's computer and convert them to a .RENSENWARE format, making the files unusable. But unlike other ransomware, RensenWare requires the victim to play Touhou 12: Unidentified Fantastic Object and score 200 millions in the Lunatic (hardest) difficulty. Unfortunately, Touhou 12 is not included with RensenWare, making the victim's files completely locked if they do not own Touhou 12. Also, if they do not reach that score or terminate the RensenWare process, their files will be encrypted forever.
After RensenWare spread worldwide, Park Shinjo later apologized on Twitter, claiming that it was made as a joke. He also noted that his computer was infected by the ransomware.
When Malware Hunter team found out about RensenWare, they released a program that forced Touhou 12 to achieve a score of 200 million to unlock all files encrypted by RensenWare.