Ransomware is a specific category of malicious software designed to block access to a computer system or data, typically by encrypting files, until a sum of money (a ransom) is paid. The malware's primary function is to hold the victim's data hostage, demanding payment for the decryption key to restore access. This directly matches the scenario described in the question, where data is held hostage in exchange for a ransom payment.

A. Trojan: A Trojan is a delivery mechanism that disguises malware as legitimate software; it does not inherently hold data for ransom.

B. Virus: A virus is self-replicating code that attaches to other programs to spread. Its primary purpose is propagation, not extortion.

D. DoS: A Denial-of-Service (DoS) is an attack type, not malware, that makes a service unavailable. It does not involve encrypting data for a ransom.

1. National Institute of Standards and Technology (NIST). (n.d.). Glossary: Ransomware. Computer Security Resource Center. Retrieved from https://csrc.nist.gov/glossary/term/ransomware.

Reference Point: The glossary defines ransomware as "A type of malicious software that infects a computer and restricts users’ access to it until a ransom is paid to unlock it."

2. University of California

Berkeley. (n.d.). What is Ransomware? Information Security Office. Retrieved from https://security.berkeley.edu/education-awareness/what-ransomware.

Reference Point: The "What is Ransomware?" section states

"Ransomware is a type of malware that encrypts your files

holding them hostage until you pay a ransom to the attacker."

3. Kharraz

A.

Robertson

W.

Balzarotti

D.

Bilge

L.

& Kirda

E. (2015). Cutting the Gordian Knot: A Look at Ransomware Attacks. In Proceedings of the 12th International Conference on Detection of Intrusions and Malware

and Vulnerability Assessment (DIMVA) (pp. 3-22). Springer. https://doi.org/10.1007/978-3-319-20550-21

Reference Point: Page 3

Section 1 (Introduction)

Paragraph 1: "Ransomware is a particularly nasty type of malware that prevents victims from using their computer or accessing their personal files until a ransom is paid."