What does the 'crypted' box mean in the Unity Pro v4.1 project's password protection?

Goals and Symptoms

What does the 'crypted' box mean in the Unity Pro v4.1 project's password protection?

Causes and Fixes

If you right click on the project name in the browser and choose <Properties><Protection> and check the <Protection Active> box, you are presented with the 'crypted' box.
This is a high level of encryption normalized on 128 bits. This option is available on Unity Pro v4.1 or higher.

Note: A project with a crypted password cannot be edited with a Unity Pro version lower than 4.1.