3) Double-DES is two successive DES instances, while Triple-DES is three successive DES instances. We use 3DES and not 2DES because 2DES does not yield the security increase that we expect. Please answer the following questions regarding 2DES a) Partial credit 1: Evplain how meet in the middle attack can occur in 2DES through drawing the schematic view and the tables corresponding to this attack. [1 point] b) Partial credit 2: What it the time complexity of this attack? [0.5 points 4 Electronic Code Book (ECB) is a mode of operation for a block cipher. Explain why ECB is not a good use of PRP for building secure block ciphers? [0.5 point] 5) Nonce-based encryption has been implemented in HTTPS and IPSec design. Please explain how nonce has been implemented in these two protocols. [I point) HTTPS: IPSec