"ProtonMail offers a user-friendly experience with full “end-to-end” encryption. It encrypts the data on the browser before it communicates with the server, therefore only encrypted data is stored in the email service servers. So, even if someone gains complete access to the server, it will find only the encrypted data. Moreover, there is even a “self-destruct” feature in the email service which ensures your emails are only available for a limited period of time."
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