10. [6 marks, 3 per part] 11. (a) Encrypt the message MEET ME AT NOON using blocks of 4 letters and the transposition cipher based on the permutation of {1, 2, 3, 4} with 0(1) 2 3, 0(2) 2 1, 0(3) 2 4, 0(4) 2 2. (b) What is the decryption function of this cipher? Use it to decrypt the message LOAM THST EDEN. What was the plaintext message? [10 marks, 5 per part] (a) Encrypt the message MATH using the RSA system with n = 61*79 and e = 7. First translate each letter into an integer (in the range [0, 25]) and group together pairs of integers, so you have two 4digit numbers (padding 0's in the front if necessary). (b) Suppose that (n = 61*?9, e = 7) is the public key. Find the private key and show how this private key is used to decrypt the ciphertext message: 1519 22271111. (Calculate the value of the private key, but do not do the calculations in the decryption, only show what they should be.)