Our requirement is to send email securely from our embedded device running on STM32H7 processor. There's an SMTP client application (implemented using Mbed TLS library) running on this device, which will send emails to the recipient via custom/public email server such as smtp.gmail.com. We are planning to use S/MIME email certificate from the one of the Trusted CA, for encryption of the email message and authentication of the client/server. We learnt that each S/MIME email certificate support only one email address, but we will be having multiple devices running on the field and each device will have unique email address from which email will be sent. Getting S/MIME email certificate for device will not be feasible, is there any better way we can handle this scenario effectively. Your response to this problem is greatly appreciated.
Thank you, Nagaraj