Suppose that we define triple 3DES with a 168-bit key as C = E(E(E(P,K 1 ),K 2 ),K 3 ). Suppose that we can compute and store a table of size 256, and a chosen plaintext attack is possible. Show that...

Suppose that we define triple 3DES with a 168-bit key as

C = E(E(E(P,K₁),K₂),K₃).

Suppose that we can compute and store a table of size 256, and a chosen plaintext attack is possible. Show that this triple 3DES is no more secure than the usual 3DES, which only uses a 112-bit key. Hint: Mimic the meet-in-the-middle attack on double DES.