As far as I can tell you can't use the fact that key 1 and 2 are a known distance away from each other to discern anything about them. It's a single equation with two unknowns. Example: X + Y = 123, but X and Y could be 0 and 123, or they could be -113258881385746098181140976018376643534 and 113258881385746098181140976018376643657, or any other number.