Alice and Bob use the Die-Hellman key exchange protocol with common
prime modulus p = 11 and common base a = 2. An eavesdropper who knew
p and a noted that the number Alice sent to Bob was yA = 9 and the number
Bob sent to Alice was yB = 3.
a. What was Alice's secret random number xA?
b. What was the common secret key K generated for Alice and Bob by the
protocol?