Just a few years ago, you may never have heard of ransomware. Nowadays, it’s a £10 billion-a-year industry and considered one of the biggest threats facing organizations, schools and essential services.

Dozens of ransomware cases are reported each month, with companies locked out of their files and facing extortionate demands. The current going rate for decryption keys is in the region of 0.3 bitcoin (about £100,000, or $140,000), but sometimes attackers set their sights much higher.

In this blog, we look at some of the times attackers have done that – as we review the five biggest reported ransomware payments.