The WordPress Security Admin is found within its own module and can be accessed from the main Shield menu under "Security Admin".
It restricts access to the WordPress Shield Security plugin preventing unauthorized changes to your security settings.
To understand how the Security Admin works, read the article here.
How to turn on the Security Admin
To turn on the Security Admin, you just need to enter a new Security Admin Access key and specify an automatic timeout interval for Security Admin access. (See the screenshot below)
What is the "Access Key"?
Access Key is a password that you create. It can be anything you want. You must remember it as if you do not, you will not be able to access the setting of the WordPress Shield Security plugin.
Important: If you do not enter the Access Key, the option will not be enabled.
How to turn off the Security Admin
To turn off Security Admin you must be authenticated with the plugin first (you have to provide access key), and then go to Security Admin module => Enable/Disable Module and click the slider to disable it.
For more information about the Security Admin, read the blog article here.
Note: If you happen to have lost or forgotten your access key, you can disable the feature altogether and re-enter a new access key. Read here on how to do that.