CSCI 391 Practical Cryptology Spring 2015
RSA TEST PART 1

Answer all questions. Provide detailed explanation.
Open Material

IMPORTANT: Use base 26 system while converting strings to numbers

For numeric values of letters see HERE

• Problem 1 (25 points): Alice chooses the fllowing private key: p = 23, q = 113, and e = 11. She publishes her public key: m = 2599, e = 11, and receives the following ciphertext from Bob: 783. Find d and decrypt the message, or explain why it is impossible.

• Problem 2 (25 points): Alice publishes the following public key: m = 731 and e = 29. Bob would like to send Alice the following message: CAT. Encrypt the message or explain why it is impossible.

• Problem 3 (25 points): Alice publishes the following public key: m = 731 and e = 29. Bob would like to send Alice the following message: GO. Encrypt the message or explain why it is impossible.

• Problem 4 (25 points): Alice chooses the fllowing private key: p = 23, q = 113, and e = 13. She publishes her public key: m = 2599, e = 13, and receives the following ciphertext from Bob: DPR. Find d and decrypt the message, or explain why it is impossible.