PapaWolf

I have a question which I'm not too sure if it has been asked before as this is my first post. Does anyone have a clue as to who Coldhands is? I had the feeling that it was Benjen Stark as he is wearing the black of the NW and he knows how to find the black gate although you never find out. Could Benjen have found Bloodraven when he disappeared due to having the blood of the first men and then been set the task to bring Bran to BR?