Ransomware is a special form of malicious software that literally “kidnaps” third-party data: attackers use ransomware to encrypt the (private and sensitive) data of their victims and demand a ransom for a key with which the affected parties can supposedly unlock their data once more. A prominent example on a vast scale was the WannaCry attack of May 2017: In the attack, a crypto-Trojan encrypted and locked thousands of computers worldwide.