The normal captcha is a PHP native solution which does not require any API keys.
Step 1: Generate the shortcode
In our example, we use the new Shortcode generator to generate our shortcode.
We choose “Captcha” as our protection type hit save and were done!
Step 2: Customize the settings (optional)
You can customize the behavior of your Captcha under Settings->Passster->Captcha.
Modify the generated length of the captcha code or use only numbers to make it less difficult to unlock your content.
Step 3: Add it to your content
Now we can switch to our blog post, page or any other custom post type and paste in our generated shortcode: