(Chosen Ciphertext Security). Let E = (G,E,D) be a public-key encryption over (M,C). a) Describe the security game of IND-CCA security (hints: slides p22)

b) Suppose an active attacker can convert the ciphertext of 1 = (:@, ) to the ciphertext of 2 = (:@, ), i.e., given 1 = (, 1), the attacker can obtain 2 = (, 2), Following the slides p23, show that this encryption algorithm is not CCA secure.