Costumes/Hair

For costumes we were thinking of something similar to men in black, where we would use dark suits and sunglasses. The hacker would wear a beanie and sunglasses to cover his face so we don't know who he is. This would also help because we may need the actor to play another character as well and we don't want the audience to guess that the same actor is playing both roles so we will dress them very differently and cover their face. They will also be filmed mostly from behind so avoid many close ups of the hackers face.
For Hair, we might slick the government agents hair back if it is long enough but this may not be possible so it is likely that we will leave it.