Ransomware is the name given to malicious programs designed to extort money from their victims, by blocking access to the computer or encrypting the data stored on it.
The malware displays a message offering to restore the system in return for a payment.
Sometimes the cybercriminals behind the scam try to lend credibility to their operation by masquerading as law enforcement officials.
Their ransom message asserts that the system has been blocked, or the data encrypted, because the victim is running unlicensed software or has accessed illegal content, and that the victim must pay a fine.
While anti-malware software can detect and block ransomware programs, it may not be possible to decrypt the data.
So it’s a good idea to take regular backups, to avoid data loss resulting from ransomware (as well as to safeguard against data loss because of other computer problems).