What type of malware is it that restricts access to a computer system that it infects and demands that the user pay a certain amount of money, cryptocurrency, etc. to the operators of the malware to…

Ransomware is a class of malware that either encrypts victim files or locks the operating system entirely, making data or the system inaccessible to the legitimate user. The attacker then demands a ransom - commonly in cryptocurrency - in exchange for a decryption key or removal of the access restriction. This extortion-based model is the defining characteristic that distinguishes ransomware from all other malware categories.

Riskware refers to legitimate software that carries potential security risks if misused or exploited, not malware that actively restricts access and extorts victims.

Adware displays unwanted advertisements to generate revenue for its operator and does not restrict system access or demand any form of payment from the victim.

Spyware secretly monitors and collects user data or activity without consent, but it does not restrict access to the system or demand a ransom payment.