I have 2 Cat6 cables running between two buildings. They are underground (except where they go into the buildings). I need to make sure someone cannot merely cut the cable, attach a plug to it and plug it into a laptop thus having the same access as the computers inside the buildings. The cables inside the buildings are connected to a vanilla switch. All the inside computers are passworded etc., but this would still give someone a good start at hacking. Is there some kind of encryption devise that could go inside each building at the switch to protect the data going across the cable?