Install and use an S/MIME certificate on iPhone / iPad

Manipulations carried out on an iPhone 13 equipped with iOS 17.4.1.

It is now possible to install an S/MIME certificate on an iPhone or a iPad and therefore sign or encrypt your emails from the Mail application of your mobile tool.

It is also possible to use a client certificate for authentication purposes.

Prerequisites

• iOS 5+
• a pfx or p12 file: Apple recommends that the file be recovered by the tool via a file attached to an email. It is also possible to recover the file in p12 format directly from the supplier at the time of delivery (depending on each authority process).

Profile installation

Open the pfx or p12 file by selecting it. This will start the certificate installation process as a new profile on your tool:

Then go to the settings to finalize the installation of the profile. The profile downloaded appears:

Click on the profiles then on "install":

You will then be asked for the password for your p12 / pfx file:

Enter the password then click “Next” to finalize the profile installation. A confirmation is displayed:

Using the certificate

Once the profile is correctly installed, you must modify the settings of your Mail account to sign and/or encrypt your emails.

To do this, go to “Settings” > “Mail” > “Accounts” > choose the account on which will be active the certificate then
"Account settings" > "Advanced settings":

In the "S/MIME" section you can choose to encrypt or sign your emails by default.

Click "Sign", activate the signature and choose the certificate to use:

Repeat the same operation for encryption.