Ransomware is a type of malware that is a form of extortion. It originates from cryptovirology and threatens to publish the victim’s data or permanently block access unless the attacked person (victim) pays the ransom. Typically, ransomware encrypts the victim’s files on the computer, making them inaccessible. The victim must then pay a ransom to decrypt the files and reaccess them.

In a properly implemented cryptoviral extortion attack, recovering the files without the decryption key is complex. It is also tough to trace because attackers usually use payments with Paysafecard, digital currencies (cryptocurrencies) to receive a ransom.

A typical ransomware attack starts with a Trojan disguised as a legitimate file that the user is duped into by downloading or opening an email attachment. However, one high-profile example, the WannaCry worm, travelled automatically between computers without user interaction.