You may have seen the USA Network's hacker drama "Mr. Robot," which ended its first season in August. The television show was widely praised by technophiles for its accuracy in depicting the latest hacking technology and security protocols.
The main character in "Mr. Robot," Elliot Alderson, uses something called ProtonMail for his encrypted emails. ProtonMail is real, and it's as secure as you can get when it comes to protecting your email's privacy (email by its very nature can never be 100% secure, as ProtonMail's developers acknowledge). The browser-based email service has been described as "NSA-proof."
The NSA reference is apt - ProtonMail's founders came together and created the service after the Edward Snowden revelations about NSA spying in summer 2013. The founders were working together at CERN, the European Organization for Nuclear Research, where the World Wide Web was created in 1989.
ProtonMail's primary attraction, and the reason for its security claims, is that it uses end-to-end encryption. Also, your data isn't available to ProtonMail - you actually use two passwords, one to identify yourself as the user, and another, which ProtonMail never sees, to decrypt your inbox, as seen below. Click here to learn how to create a super-strong password.
Since ProtonMail doesn't know your mailbox encryption key, even if its servers were subpoenaed, the company wouldn't be able to decrypt the data.