CSCI 391 Practical Cryptology Spring 2015
RSA TEST Part 2
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
- (20 points) Find 23^73 mod 19 using fast modular exponentiation.
Write your
calculations for all steps.
- (20 points) True or False: with m = 24589181 and e= 13 it is possible
to encrypt any
all 5-letters words. Explain your answer.
- (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.
- (20 points) Suppose you know m = 22771241 and e = 13. Find p, q and d
and decrypt
the following message: BNKGLK
- (20 points) Suppose you know m = 192469, n = 191296 and e = 11. Find p
and q using
quadratic equation solutions. Find d and
decrypt the message EVEG.