You can set the machine to only receive encrypted secured print jobs from computers.
For information on the optional products required to use this function, see "Optional Products Required for Each Function."
1.
Press 
→ [Function Settings] → [Encrypted Secure Print] → [Only Allow Encrypted Secure Print Jobs].
→ [Function Settings] → [Encrypted Secure Print] → [Only Allow Encrypted Secure Print Jobs].2.
Select [On] or [Off] → press [OK].