Ransomware is when an attacker has got hold of your files and asks for ransom to be paid in return for your files.
He could get this by installing malware that changes your passwords,email id, or by encrypting your files.
Generally the ransom demanded is through cryptocurrencies so that it becomes impossible for the authorities to find who the man was behind the attack.
According to a report: he Ransomware Protection Market was valued at USD 11.93 billion in 2019 and is expected to reach USD 29.07 billion by 2025
Crypto-malware is a malware(ransomware) that encrypts your data and holds it for ransom. It encrypts everyting execept for the OS.
The aim is to keep your computer running but prevent your from doing any work.The computer becomes pretty useless, as all the files and programs have been encrypted and rendered un-usable.
These type of malwares get installed on your system by taking advantage of known vulnerabilities.