Question:

(a) Explain how the Diffie-Hellman key establishment protocol works.

(b) Prove that the Diffie-Hellman key establishment protocol is vulnerable to a `man in the middle attack '.

(c) Alice and Bob uses the Diffie-Hellman protocol to communicate. In order to be certain that they are communicating with each other, they introduce authentication into the key establishment protocol by making use of the Key Exchange Algorithm. Explain how the Key Exchange Algorithm works.