You can prevent the names and photos of incoming callers from appearing on the lock or security screens. 
	 
 
  
 
	 
		Important: The caller must be in your private contacts list.
		
	  
	 -  
		  Go to Settings, and then tap 
				Security. 
			  
		
-  
		  Under 
			 Lock screen, select 
			 Incoming phone calls.