The Persona is a combination of the following parts:
See page 211 SR4 (Persona)
Commcode (ID)
Hardware
Software
So, as long as you have two commlinks and two commcodes you can make your Drones a bit safer from spoofing, not fool proof but safer.
Persona 1 (commlink 1) grants user access to Persona 2 (Commlink 2) to Drone 1.
Shut down Commlink 1 or at least log off from the matrix with it.
Access the matrix with persona 2 and command your drone. Anyone analyzing the persona that commands the drone will not get anything but user access even if they demand it and succeeds with the diceroll because the Drone is not allowed to give that persona a higher access.
Depending on what one can do with a user access (that’s up to the owner) but I would limit it to regular Rigger commands like move, target, shoot, analyze etc. Changing subscription lists and the like would be at least security access.