For any block cipher, the fact that it is a nonlinear function is crucial to its security. To see this, suppose that we have a linear block cipher LIN that encrypts 128-bit blocks of plaintext into 128-bit blocks of ciphertext. Let LIN(K, m) denote the encryption of a 128- bit message m under a key k (the actual bit length of k is irrelevant). 4. Then by linearity for all 128-bit patterns m ,m2. Describe how, with 128 chosen ciphertext attacks, an adversary can decrypt any ciphertext without knowledge ot the secret key k (In a chosen ciphertext attack the adversary can choose any ciphertext and obtain its decryption. Here, the adversary needs to choose 128 appropriate ciphertexts and use the corresponding plaintexts to get the decryption of any ciphertext.)