1. Let X’ be the bitwise complement of. Prove that if the complement of the plaintext block is taken and the complement of an encryption key is taken, then the result of DES encryption with these...

1. Let X’ be the bitwise complement of. Prove that if the complement of the plaintext block is taken and the complement of an encryption key is taken, then the result of DES encryption with these values is the complement of the original cipher text. That is,

IfY= E(K,X)

ThenY’ = E(K’,X’)

2. Show that in DES the first 24 bits of each sub key come from the same subset of 28 bits of the initial key and that the second 24 bits of each sub key come from a disjoint subset of 28 bits of the initial key.