Alice and Bob use the Diffie-Hellman key exchange protocol with the common prime p= 157 and generator g=5. a) ( 2 points) Suppose Alice picks her private number as a=64. Determine the public message she should send to Bob. Show your steps. b) (2 points) Suppose Bob picks his private number as b=94. During the key exchange phase, he received the number calculated in (a). Determine the shared secret key, kAB. Show your steps