Gmail uses TLS, or Transport Layer Security, by default for all email communications, so all of your emails will use the standard encryption as long as the recipients also support TLS. But there’s a way to add even more security to your Gmail emails, and you can use your iPhone’s Mail app to do it.
Apple has supported S/MIME, or Secure/Multipurpose Internet Mail Extensions, on iPhone since iOS 5 over ten years ago. S/MIME is a widely accepted cryptographic protocol for sending and receiving digitally signed and encrypted messages, and it works on top of Gmail’s TLS system. S/MIME is similar to PGP, or Pretty Good Privacy, which ProtonMail, FlowCrypt, and Hushmail.
The TLS used by Gmail encrypts the tunnel between email servers, so it’s harder for hackers to eavesdrop or snoop on communications while en route. Also encrypted is the connection between email clients and email servers. So as long as you’re communicating with somebody whose email provider uses TLS, the route to and from is secure. Still, email remains vulnerable at each end.
Gmail can and does scan your emails for intelligent features such as malware detection, calendar integration, and autocomplete, so if there’s a particularly sensitive topic in the email, you may want to protect it further. Gmail’s servers could also become penetrated by attackers one day, possibly giving hackers access to all your…