A type of malware that limits or prevents a user’s access to their system. The malicious software may either lock the computer’s screen or the user’s files—often through encryption—until a ransom is paid, typically using an encrypted digital currency like bitcoin. Like other types of malware, ransomware can be spread through email attachments, infected software, infected external storage devices or compromised websites, although a growing number of ransomware attacks have used remote desktop protocols. Its motive is almost always monetary.