please explain step by step. I have no idea what is happening here.

Question 1: As stated in Sect. 3.5.2, one important property which makes DES secure is that the S-boxes are that S1(xi) 51(x2)+51(x1x2), where "@" denotes bitwise XOR, for: a. X1 = 000000, X2 = 000001 b. x1 = 111111, x2 = 100000 C. x1 = 101010, X2 = 010101 a) x = 000000 X2=0000 OM S, (000000) = 1410 = 1110a Si (X) = 11102 S, (00 0001) - S, Cand now, 154 colum) - 0010 0000&