Q2 Using the English alphabet (i.e., mod 26 arithmetic) let plaintext = {p1, p2, pn} and corresponding cipher text = {c1, c2, cn}. Suppose the encryption function is ci = pi + 10 (mod 26). You receive the cipher text message EWEM SC K QBOKD CMRYYV What are the decryption function, and the decrypted/recovered plaintext? What type of cipher is this? Show your steps.

Q3 You are Alice. You have agreed with your friend Bob that you will use the Diffie-Hellman public-key algorithm to exchange secret keys. You and Bob have agreed to use the public base g = 7 and public modulus p = 1013. You have secretly picked the value SA = 17. You begin the session by sending Bob your calculated value of TA. Bob responds by sending you the value TB = 839. What is the value of your shared secret key? Can you guess Bobs secret value SB and what it would be? Show each and every step of your calculations (for mod calculation, the following identity may be useful mod( X^n, p) = mod (mod(X,p)*mod(X^n-1, p), p) mod(X*Y,p) = mod(mod(X,p)*mod(Y,p),p)