How to converse securely in a conference

A conference key is a secret common key among a group of users by which they can encrypt and decrypt messages to converse securely in a conference. This paper proposes a conference key distribution protocol for networking system. A lock is used to lock the conference key and is constructed such that only the private keys of legitimate users are matched. Therefore the lock is then put on the pubic directory or communicated to the attended users, only legitimate users can open it and reveal the conference key. The construction of a lock is straightforward and the revelation of conference key is quite simple