Alice & Bob
    Identity CA
    MTA Identity
    MTA Transport

Communication Entities

Communication Entities
Communication Entities
The diagram to the right shows the main entities that are part of the system. There can be an unlimited number of Mail Transfer Agents (MTA) that transport and store encrypted messages and a large number of Certificate Authorities that manage user identities. The client does everything that involves encryption and key-management and it ensures that confidential information stays where it has to be: at the client side only. The user is represented by the famous pair Alice and Bob and our attacker is called Eve.