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 EnLinear that encrypts $256-$bit blocks of

plaintext into $256-$bit blocks of ciphertext. Let EnLinear $(k,m)$ denote the encryption of a

$256-$bit message $m$ under a key $k($the actual bit length of $k$ is irrelevant$).$ Thus,

EnLinear$(k,[m1o+m2])=$EnLinear$(k,m1)o+$EnLinear$(k,m2)$ for all $128-$bit patterns $m1,$

$m2.$

Describe how, with $256$ chosen ciphertexts, an adversary can decrypt any ciphertext

without knowledge of the secret key $k.($A "chosen ciphertext" means that an adversary

has the ability to choose a ciphertext and then obtain its decryption. Here, you have $256$

plaintext$/$ciphertext pairs to work with, and you have the ability to choose the value of the

ciphertexts. ANSWER THE QUESTION USING MATH ONLY!