We know that an encryption scheme (Gen; Enc; Dec) with message space Mis perfectly secret if and only if Pr[Enck (m) = c) = Pr[Enck|(m') = c) prove that the Vigenere cipher is not perfectly secret. We know that an encryption scheme (Gen; Enc; Dec) with message space Mis perfectly secret if and only if Pr[Enck (m) = c) = Pr[Enck|(m') = c) prove that the Vigenere cipher is not perfectly secret