Which device are you referring to? Each device has similar or completely different features. I will be happy to assist you further if you can provide me the device you are referring to.
As a general thought, set as secret may be the ability to privatize (hide) your contacts on your device from anyone viewing them or accessing them in the contact list. This feature may have the option to retrieve them via password or code. Once I know your device I will be able to tell you more accurately.