With a S/MIME certificate, you can both sign and encrypt your e-mails. Those e-mail certificates are often used by businesses in order to increase their e-mail privacy and trust. But an e-mail certificate for personal use can be very useful as well – and can come across very professional – and it can be free as well.
Free S/MIME certificates
In the past, a number of certificate vendors offered free S/MIME certificates to the public (to personal e-mail addresses, that is). Perhaps the best known example was Comodo, who furthermore also had a very simple user interface to create, manage and renew an e-mail certificate. It also had to be renewed only once a year, in contrast with other offerings from different companies where a monthly renewal was required.
Unfortunately, after searching some time for free SMIME e-mail signing and encryption, I couldn’t find any solution that has no cost attached to it. It seems like all providers stopped offering this service: they either completely stopped offering this, or they stopped offering the free version.
Paid S/MIME certificates
While free S/MIME client certificates appear to be no longer offered by any company, there are still quite some companies offering a paid solution for signing and/or encrypting e-mails.
Here is a non-exhaustive overview of e-mail client certificates:
- SSL.com: Personal Basic Email and ClientAuth Certificate
- Sectigo.com: Secure Email Solutions (S/MIME)
- Globalsign.com: Secure Email – Digitally Sign & Encrypt Emails
Often, these certificates are not very costly, with even sometimes discounts when purchasing for multiple years.
Create your own S/MIME certificate
Given there are basically no providers of free S/MIME certificates today on the market, you may want to create your very own client certificate for your e-mails. This is completely free and you will learn more about encryption in creating your self-signed S/MIME certificate from scratch.
John Dalesandro has a great how-to blogpost for this. There are other guides available: ServerFault, Henry Todd. All these guides will help you create your own S/MIME cert in no time.