Blucube

If your site has an SSL certificate you might find that you can access the site via both SSL (https) and non-SSL (http) URLs. This is a bad idea for security, and for SEO, as it can look like duplicate content on different URLs.
The answer to this is to redirect requests to non-SSL (http) URLs over to their SSL (https) equivalents using something called a 301 redirect. This tells the client (and search engines) that the resource they are looking for should always be accessed over SSL. This plugin offers two methods to achieve this:
<ul>
<li>By intercepting WordPress pages at header time, and if they are not already being requested over HTTPS sending a 301 redirect header, or</li>
<li>By adding mod_rewrite rules in the .htaccess file to redirect all requests to their HTTPS equivalents using 301 redirects.</li>
</ul>
Optionally, this plugin can also set <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security" rel="nofollow ugc">HSTS</a> headers for you, and make sure that all requests use the same hostname (i.e. fixing the issue where many sites can be accessed using both www. and non-www. URLs).

Simple SSL Redirects

Lightweight plugin to ensure access via SSL/HTTPS. Uses 301 (permanent) redirects for SEO benefits. Optionally sets HSTS and forces canonical domain.

Ebrahim Shafiei (EbraSha)

Abdal Security Headers is a powerful WordPress plugin that enhances your website’s security through HTTP security headers. It provides an easy-to-use interface for managing security policies and protecting against common web vulnerabilities.
Key Features:
<ul>
<li>Modern UI with iOS-style switches</li>
<li>Real-time CSP Header Preview</li>
<li>Automatic security header configuration</li>
<li>Protection against XSS attacks</li>
<li>Prevention of clickjacking attempts</li>
<li>MIME-type sniffing protection</li>
<li>Strict HTTPS enforcement</li>
<li>Full RTL support</li>
<li>Mobile-responsive interface</li>
</ul>
Security Headers Managed:
<ul>
<li>X-Frame-Options</li>
<li>X-XSS-Protection</li>
<li>X-Content-Type-Options</li>
<li>Strict-Transport-Security (HSTS)</li>
<li>Content-Security-Policy (CSP)</li>
<li>Referrer-Policy</li>
<li>Feature-Policy</li>
<li>Access-Control-Allow-Origin</li>
</ul>
<h3>Languages</h3>
This plugin is available in the following languages: 
– English (en_US) 
– Persian (fa_IR)
<h3>License</h3>
This plugin is released under the GPLv2 or later License. 
License details: <a href="http://www.gnu.org/licenses/gpl-2.0.html" rel="nofollow ugc">http://www.gnu.org/licenses/gpl-2.0.html</a>

Abdal Security Headers

Enhance WordPress security with essential HTTP security headers, protecting against XSS, clickjacking, and other common web vulnerabilities.

Simple SSL Redirects vs Abdal Security Headers