A plugin for signing all outbound emails with an S/MIME certificate.
As of April 2026, S/MIME Email Signing is a WordPress email plugin with 0 active installations and a 0/5 rating0. It has been downloaded 191 times in total. Requires WordPress 6.7+ and PHP 7.2+. Available on WordPress.org since 2025. Top alternative: WP Mail SMTP by WPForms – The Most….
This plugin is for signing all outbound emails with an S/MIME certificate.
It uses phpmailer to automatically sign emails. Here are the prerequisites to use this plugin:
* This plugin is for single-user WordPress site, such as a personal blog. I don’t know what will happen if you put it in a multi-user site.
* PHP 8.3 and above are recommended. Make sure your PHP has openssl extension, which is usually installed by default.
* You should use another plugin, such as FluentSMTP, to send emails through an external SMTP server.
| WordPress | 6.7+ requiredTested up to 6.8.5 |
| PHP | 7.2+ required |
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