ProtonMail, a Switzerland-based provider of a free encrypted email service founded by scientists from Cern, was hit with a ransom demand after experiencing two apparent DDoS attacks that shut the site down, according to ITProPortal.

In a statement, the company explained it was hit by two separate groups, one likely a nation-state actor, and paid a ransom demand of 15 bitcoin (around $6,000), but the attack continued.

"DDoS for Bitcoin groups have taken their tactics from old-time protection schemes," Terrence Gareau, chief scientist at Nexusguard, told "Instead of knee caps, they DDoS your infrastructure. Sometimes before they offer the ransom and sometimes after, yet under no circumstances should the ransom ever be paid. They will keep raising the price until it is impossible to pay."

ProtonMail claimed it had not been breached, only disabled, and that all user data was safe.