ProtonMail, an end-to-end encrypted email provider in Switzerland, paid almost $6,000 in ransom in order to put an end to an advanced denial-of-service attack that shut down its networks this week. The company revealed the news in a blog post explaining that they paid the ransom via bitcoins. The attacks continued after the payment was made, but they eventually stopped. Critics suggest that by paying the ransom, the company is encouraging more attacks.