To keep your mural extra private, you can protect it with a password. You'll find this option under the Visitor link tab when you share a mural.
1. Click the pink Share button on the upper right-hand corner of the canvas.
2. Choose the Visitor link tab in the modal window.
3. On the bottom left corner of the modal, choose Add password.
Visitor link's password is not supported on the iOS app. Collaborators trying to access will receive an error and would have to visit the mural via the web app.
Now you can have more control over who accesses your visitor links.