How is "ransomware" characterized?

Ransomware is characterized as a type of malware that specifically targets data by encrypting it, making it inaccessible to the user. Once the data is encrypted, the ransomware will demand a ransom payment from the victim in exchange for the decryption key, which is necessary to restore access to the encrypted files. This form of malware is particularly malicious because it not only disrupts access to important files but also places victims in a difficult position where they must weigh the risks of paying the ransom against the potential for losing critical data permanently.

In contrast to the other options, which describe different types of threats or functions: the first option suggests a destructive malware that erases data, which does not align with the behavior of ransomware, as ransomware typically encrypts data rather than deleting it. The second option mentions spyware that steals information, which is a different category of malware focused on data theft rather than ransom for encrypted data. The fourth option describes a program that enhances data security, which is not a characteristic of ransomware at all, as ransomware is inherently a security threat rather than a protective measure. Thus, the defining characteristic of ransomware is its method of encryption and subsequent demand for ransom, making option three the correct choice.