Q2. You are asked to build a system for carpooling. The idea is that users can get rides with other users, but want to keep it fair. So for example, if Alice offers a ride to Bob and Ahmed, she should be able to get free rides (of the same value) in return. Furthermore, Bob and Ahmed should each provide rides of equivalent value to some other user. Furthermore, for simplicity, we will consider that all rides values are in the range from 1 to some upper value n (based on distance, for example). We should be able to produce a report of ride credit and debt for each user when needed. The system should ensure we can achieve authentication, non-repudiation, integrity, and confidentiality of all ride transactions and data. You are asked to: (a) outline the system/protocol (please express your answer in protocol notation or as an interaction diagram) to fulfill those requirements; (b) show all assumptions and preconditions; and (c) show/prove that the requirements are met