I am learning LISP by EMACS. I have no idea how to minus two numbers and square numbers from two lists

For example: List1(1 2 3) List2(1 3 4). First I minus them, 1-1=0, 2-3= -1, 3-4= -1, then square the number 0^2 = 0, (-1)^2=1, (-1)^2 =1

Finally I need to sum numbers: 0+1+1=2

I must use following defun command to start:

(defun sum (list1 list2 &key (test #'squared))

I need to test it by following codes:

(sum '(1 2 3) '(1 3 4)) :test #'squared) -> 2