The terms 'Maze, Petya and WannaCry', mentioned in the news over the last few years, are related to

Maze, Petya and WannaCry are all ransomware, a form of cyber attack that encrypts files and demands payment.

They are not mobile apps, which are ordinary programs for phones and tablets.

They are not crypto-currencies, though ransomware often demands payment in crypto.

They are not virtual reality, which is an immersive simulated environment.

WannaCry spread worldwide in 2017 by exploiting a Windows vulnerability.

Ransomware defence relies on backups, patching and cautious email habits.