What type of malware often demands payment to regain access to data?

Ransomware is a specific type of malware designed to deny access to a computer system or data until a ransom is paid. It typically encrypts the victim's files, rendering them inaccessible, and then presents a message demanding payment, usually in cryptocurrency, to provide the decryption key or restore access. This method of extortion can significantly disrupt an individual's or an organization's operations, as critical data may become unavailable, prompting the victims to consider paying the ransom to recover their important information.

In contrast, viruses replicate themselves and can infect other files or systems, but they do not typically hold data hostage. Worms can spread across networks independently and often exploit vulnerabilities but do not demand payment. Spyware secretly gathers user information without consent, primarily aimed at data theft rather than ransom. Thus, ransomware is distinctly characterized by its demand for payment in exchange for data access, making it the correct answer.