Proton Mail is an end-to-end encrypted email service founded in 2013 in Geneva, Switzerland.[5] Proton Mail uses client-side encryption to protect email content and user data before they are sent to Proton Mail servers, unlike other common email providers such as Gmail and Outlook.com.[6] The service can be accessed through a webmail client, the Tor network, or dedicated iOS and Android apps.Proton Mail is run by Proton AG, which is based in the Canton of Geneva.[8] The company also operates Proton VPN, Proton Drive and Proton Calendar. Proton Mail received initial funding through a crowdfunding campaign. Although the default account setup is free, the service is sustained by optional paid services. Initially invitation-only, Proton Mail opened up to the public in March 2016. In 2017, Proton Mail had over 2 million users,[9] growing to almost 70 million by 2022.Proton Mail uses a combination of public-key cryptography and symmetric encryption protocols to offer end-to-end encryption...