Assume you want to write a program to simulate the permutation boxes in Figure 31.8 in the text.

Figure 31.8

a. Show how you represent each box as a table.
b. Show the inversion of each box as a table.

3. 2 3 Straight permutation Compression permutation Expansion permutation Transposition bits n bits b7 b6 bs b4 b3 b2bi bo A predefined Key (n bits) function Shift left (3 bits) b4 b3 b2 b|bob7 b6 bs m bits n bits Substitution Exclusive-OR Shift b7 b6 bs b4 b3 b2bi bo b7 b6 bs b4 b3 b2 bibo b7 b6 bs b4 b3|b2b||bo bbb bob7 be bs b4 b7 b6 bs b4 b3 b2 b1 bo b7 b6 bs b4 b3 b2b bo Swap Split Combine