Suppose you are a new administrator of a small company which recently introduced a simple PKI to ensure secure e-mail communication for its employees. As a first step you analyze the IT infrastructure.
1. You recognize that the CA of the PKI synchronizes its clock daily with an unauthenticated time server. What security problems could arise from this? How could the problems be detected? What are possible countermeasures?
2. What possible security problems arise if an adversary manages to alter the clock used by legitimate clients? What are appropriate countermeasures in this case?