Suppose (KeyGen, Enc, Dec) is an IND-CPA secure symmetric key encryption. We define following new encryption algorithms, are the new schemes still IND-CPA secure? If yes, briefly explain why. If you think it insecure, give an explicit attack violating the IND-CPA definition. Recall that the intuition of IND-CPA security means the ciphertext does not leak any non-trivial information about the plaintext.

1) Enc4(, ) is defined as follows: It runs Enc(k, m) and obtains c0; it computes a permutation on the ciphertext space, for example, it computes c0 ? u for a randomly chosen u. (The decryption algorithm will be adjusted accordingly). The final ciphertext c will be u, c0 ? u