Ransomware is a shorthand way of saying "ransom malware", and much like its name implies, it is a type of malware which denies the user access to a part of their system in exchange for a ransom payment. The creator of such a program reaches out to the victim with a set of instructions (usually to send the money in the form of a cryptocurrency or through a credit card) in exchange to regain control over their machine or that part of their system.