What type of malicious software encrypts files on your system and demands payment for the decryption key?

Ransomware is a type of malicious software specifically designed to encrypt files on a victim's computer. Once the files are encrypted, the attacker demands a ransom payment from the victim in exchange for the decryption key that is necessary to restore access to the locked files. This form of cybercrime can have severe consequences, as victims may lose access to critical data or be forced to pay substantial sums to regain control over their own information.

While worms, trojans, and viruses are all types of malware, they function differently than ransomware. Worms can replicate themselves and spread across networks, trojans disguise themselves as legitimate software to trick users into installing them, and viruses attach themselves to legitimate programs to spread. None of these primarily focus on encrypting files and demanding ransom as a means of extortion, which is the defining characteristic of ransomware.