What constitutes 'ransomware'?

Ransomware is specifically defined as a type of malware that encrypts files on a victim's system, rendering them inaccessible until a ransom is paid to the attacker. The primary function of ransomware is to extort money by taking control of the victim's data, typically demanding payment in cryptocurrency to ensure anonymity. It operates by locking up essential files or entire systems, creating a critical scenario for the victim, who must then decide whether to pay the ransom for potential recovery of their data.

In the context of the other options, while malware can indeed infect networks, not all malware falls into the category of ransomware. Similarly, a type of virus that destroys data does not align with the main characteristic of ransomware since its goal is extortion through encryption rather than outright destruction of data. Additionally, spyware, which collects information without the user’s consent, is fundamentally different from ransomware in terms of intent and impact on the victim's data.

Thus, the correct definition of ransomware emphasizes its role in file encryption for financial gain, making it a distinct and significant threat within the broader category of malware.