(b) This question is about the RSA cipher, with the standard notations as in the lecture notes. i. Suppose the following parameters are chosen for the keys: n=91,e=5. Encrypt the plaintext number N + 11 with the above key, where N is the last digit of your student number. For example, if your student number is 190123456, you should encrypt the number 17, and if your student number is 219043210, you should encrypt the number 11. You should show your working steps, and in particular show how modular arithmetic can be used in the calculations to keep the numbers small and/or improve the efficiency of the calculations. [5 marks] ii. In this example, the value of n is small, so it is easy to work out the private key from the public key. Describe the steps to obtain the private key exponent d in this scenario. You do not need to actually work out the correct d value that correspond to the above given values. [3 marks]