MobileCertificate

This simple tool allows you to export your macOS certificates usable for Mail signature and encryption on your iOS and macOS devices.

The generated file must be securely transferred to your iPhone or iPad by yourself. When you open it on your mobile device, the system will show you the contents (your selected certificates) and offer you to install it.

When its done, you can read encrypted e-mails and send signed and encrypted e-mail as long as youve correctly set up the S/MIME options in your iOS mails settings.

The configuration file created by this tool can also be used to install your certificates on macOS.