Besides HLS encryption, a very useful option to secure your videos is to restrict what domains are allowed to play your videos via the embed code. If you are concerned about your embed code being found and copied to other websites then you may want to whitelist your own domains so that your embed code works on those domains only.
You can configure this globally for all videos in your account.
Just to reiterate, this feature allows you to whitelist domains you own. So if you activate this feature, you would be adding your own domains so that your embed code works on those domains ONLY.
You can set a global policy so that all of your videos only work in the domains you whitelist. To set a global rule, click on the App Settings in the bottom-left corner of the screen and then go to "Allow Domains".
By default your embed code will work on any domain.
To set your own domains just switch the toggle and then click on Add Domains.
Next, enter your own domain and then click on Create. Be sure to enter only the top level domain (without www & https):
Once you do that you will see your domain listed. You can add as many domains as you want: