Answer Happy

Q4. (c) A group of users want to communicate securely and anonymously. Essentially, they only want to allow group members to participate in the message exchange: the messages should not be readable by outsiders, it should not be possible to link a specific user to a particular message, and outsiders should not be able to insert messages into the system. They decide to use a certificate authority to certify their public keys. They believe this can solve the message security and authentication problem, but are still unable to determine how they would be anonymous when communicating with each other. You are asked to design a protocol that enables them to achieve their objectives.