Create software that can encrypt and decrypt using S-DES. Test data: use plaintext, ciphertext, and key of Problem 3.18.

Problem 3.18

Using S-DES, decrypt the string (10100010) using the key (0111111101) by hand. Show intermediate results after each function (IP, \(\mathrm{F}_{K}, \mathrm{SW}, \mathrm{F}_{K}, \mathrm{IP}^{-1}\) ). Then decode the first 4 bits of the plaintext string to a letter and the second 4 bits to another letter where we encode A through \(\mathrm{P}\) in base 2 (i.e., \(\mathrm{A}=0000, \mathrm{~B}=0001, \ldots, \mathrm{P}=1111\) ). Hint: As a midway check, after the application of SW, the string should be \((00010011)\).