Secure Socket Layers (SSL) is a technology that is used to encrypt the data sent between your server or host and a visitor to your web page.
When SSL is activated, it makes it almost impossible for an attacker to intercept data in transit, therefore making the transmission of form, password, or other encrypted data much safer. You can find a list of free/inexpensive SSL certificate providers here.
This plugin gives you the option of turning on SSL (if your server or host supports it) for all of your sites.
Note: While this plugin does give you the option of encrypting everything, SSL may not be for you. SSL does add overhead to your site which will increase download times slightly.
Enabling Enforce SSL
You can enable this feature by typing "SSL" in the Security Search Bar or by going to Solid Security > Settings > Features > Utilities >Enforce SSL.