Sophos said the problem had become much more widespread in 2013, partly because of the reason that Microsoft had protected Windows against other types of attack, the BBC reports.
According to the report, the scammers try to extort cash by using ransomware to encrypt data, preventing access, or falsely accusing people of possessing illegal material.
A particularly dangerous ransomware, called “Cryptolocker”, emerged in 2013, which used a very strong type of encryption to lock away files on a Windows computer.
Cryptolocker demands payment in bitcoins, which is a virtual currency, and many paid the ransom it demanded in the hope that the data it had encrypted would be unscrambled.
However, none of them got their data back even after paying hundreds of pounds.