Page 2 – Encrypted Email Needs Certificates
To Start Encrypting Email With iOS Mail, You Need Your Certificates
That’s the beginning point, so let’s start there. This tutorial assumes you have already set up S/MIME signatures and encryption in Apple Mail for macOS Sierra. If you haven’t, follow this how-to first. Once that’s done, you need to open Keychain Access on your Mac. Click login, then My Certificates from the left sidebar. Find your certificate. Then right-click on the certificate itself, and choose Export (your email address).
You can give your exported certificate file a name, if you want. Choose a location to save your file, remembering where you saved it. Be sure to choose the correct file format for the certificate bundle. You need to select Personal Information Exchange (.p12). Then click Save.
Keychain Access will prompt you to enter a password to protect your exported certificate. Go ahead and do so, remembering what you set as the password. When done, click OK and you’ll be able to save your certificate file.
Keychain Access will also ask you to allow the key to be exported. Click on Allow to proceed.
Finally, email your certificate file to an account on your iOS device. Once that’s done, follow these steps on your iPhone or iPad.
Next, Install the Certificate to iOS
Find the email you sent to yourself containing the certificate file. Tap on the .p12 file. A popup will appear to install the profile. iOS will say the profile isn’t signed, but don’t worry – the certificate inside that profile is signed. Tap on Install in the upper right corner.
You’ll be asked to enter a passcode, if you have one set up on your iOS device. Go ahead and do so.
A warning popup will appear, telling you the profile is unsigned. Ignore the warning (trust me), and tap Install in the top right corner.
On the next screen, tap Install at the bottom of the screen.
You’ll be asked to enter the password for the certificate, so type that in. Then, tap Next in the upper right corner.
Tap Done, and iOS will install the certificate.
Next: Setting Up S/MIME on iOS