Part 1. (40 points) Please answer all 8 questions. Each question is 5 points. 1) Which of the following is not a block cipher operating mode? A) ECB B) CBF C) OFB D) CBC E) None of the above 2) What mode is illustrated below? x, yi xi A) ECB B) CBF C) OFB D) CBC E) None of the above 3) Assume that a key length of 2DES is k bits. What is computational complexity of 2DE using Meet-in-the-Middle Attack A) number of encryption and decryptions- 2k, number of storage locations 22 B) number of encryption and decryptions 2, number of storage locations 2 C) number of encryption and decryptions 2,number of storage locations 2 D) number of encryption and decryptions 22, number of storage locations-2 E) None of the above 4) What is properties or analogies of symmetric Cryptography? A) The same secret key is used for encryption and decryption. D)All th With oande foe B) The encryption and decryption function are very similar C) A safe with one lock D) All the above E) None of the above