There are quite a few SSL certificate companies out there that offer free email S/MIME certificates. There are also paid versions as well. I need about 6 email certificates for some company email addresses (the company has yet to start trading hence the requirement to keep costs low) so what advantages does getting paid certificates have over the free certificates?

If it matters I use Microsoft Exchange Online as my email provider and use Outlook 2013 and Thunderbird as my email clients.

  • In my country, if you want an e-mail to be used as a proof in court, it needs to be ꜱ/ᴍɪᴍᴇ signed with a certificate issued through a ᴄꜱʀ (not generated in browser or served side) by a valid ᴄᴀ (otherwise defendant can deny claims you sent specific e‑mails). I’m not aware of a free and valid issuer that won’t generate the private keys for you (or won’t do it inside a browser). Such thing is only available as paid. Dec 15, 2017 at 15:38

1 Answer 1


If you have confidence in the security and policies of the company issuing the certificate (that they would not issue one to someone else for addresses in your domain) there should be no difference. Most of these shops offer the free e-mail certificates as a way to advertise to you for Web server certificates and the like. Many of the paid offerings provide insurance against anyone else getting your certificate through the company's error or by hacking their servers, and then impersonating you.

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