CSCI 391 Practical Cryptology
RSA TEST

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

Useful link: Wolfram|Alpha: Computational Knowledge Engine

1. (20 points) Find 23^73 mod 19 using fast modular exponentiation. Write your calculations for all steps.
2. (20 points) True or False: with m = 24589181 and e= 13 it is possible to encrypt any all 5-letters words. Explain your answer.
3. (20 points) Alice publishes m = 22771241 and e = 13. And Bob would like to encrypt plaintext GAME. Encrypt the message or explain why it is impossible.
4. (20 points) Suppose you know m = 22771241 and e = 13. Find p, q and d and decrypt the following message: BNKGLK
5. (20 points) Bob would like to send Alice the following message: one. First, pretend you are Alice, make the public and private key, then encrypt Bob's message. Explain.