Ransomware

Ransomware is computer malware that installs covertly on a victim’s device (e.g., computer, smartphone, wearable device) and that either mounts the cryptoviral extortion attack from cryptovirology that holds the victim’s data hostage, or mounts a cryptovirology leakware attack that threatens to publish the victim’s data, until a ransom is paid. Simple ransomware may lock the system in a way which is not difficult for a knowledgeable person to reverse, and display a message requesting payment to unlock it. More advanced malware encrypts the victim’s files, making them inaccessible, and demands a ransom payment to decrypt them. (Source: Wikipedia)