Question

1. Bob has an RSA public key of

   (n, e) = (1363, 87)

   1. (a) What is Bob’s private key?

   2. (b) Bob receives the ciphertext which has been encrypted with his public key

      893, 1265, 406, 171, 980, 1040, 12, 1152, 573

      Decrypt the message.
      (You can use an appropriate package such as Matlab or Wolfram Alpha to do the calculations)

Answer 1

Use comments section for queries:

Part-A:

Here calculations are done using Wolfram alpha

In order to calculate Bobs private key we need to find such that

where .

Here

Thus Bobs private key is .

Part-B:

Now the message can be obtained from the given cyphertext using the following way

Using Wolfram Alpha

Thus the message is