What is rensenware? (Touhou Ransomware)

Rensenware (also known as Touhou ransomware) is a type of ransomware originally created as a joke by a Korean programmer and uploaded to the GitHub community. Touhou ransomware is a type of malware that infects Windows computers and encrypts files.

Resenware is unique from other ransomware types, such as Ryuk or Sodinokibi, which call for victims to pay money to regain access to their files or systems. In order to successfully decrypt virus-locked files, the victim must download the 2009 anime Touhou bullet hell game "Touhou Seirensen - Undefined Fantastic Object" and score 200 million points on "Lunatic" mode.

Is Touhou a virus?

While the terms “malware” and “virus” are commonly used interchangeably, they are not the same. Ransomware is a type of malware that prevents users from accessing their systems unless a ransom payment is made, which can have a catastrophic impact on the victim.

How hard is it to achieve the score?

It is notoriously hard to reach the Touhou game score required for decryption. In fact, when the creator of rensenware ransomware accidentally infected his own device, he commented that even he could not achieve it.

Can I decrypt my data without playing?

If your device is infected with Touhou ransomware, you should not attempt to kill the malware program – doing so without achieving the 0.2 billion points required may mean that you lose your data permanently.

However, apologizing for his actions on GitHub, creator Typle Eraser released a cheat code that places a custom score in the game to unlock files and enable those to regain access to their folders. He shared this publicly to enable those who downloaded the original version to successfully decrypt and neutralize their devices.