Let (E,D) be a semantically secure cipher where the message and ciphertext space is {0, 1}". For the following encryption scheme E', state whether it is semantically secure. If it is, then prove its semantic security by using contrapositive (or if there is an attacker A to break E' then it is possible to design an attacker B to break E using attacker A). If it is not, design an attacker and compute the advantage. (a) E' (k, m||m') = E(k, m)||E(k, m') (b) E'(k, m) = E(k, m)||E(k, m + 1")