A new service for digital mobile communications

We propose a new service for digital mobile communication systems which enables two or more users to hold a secure conference. Two requirements must be considered: privacy and authentication. Privacy is to ensure that an eavesdropper cannot intercept conversations. Authentication ensures that the service is not obtained fraudulently in order to avoid charge for usage. We present a new conference key distribution scheme for digital mobile communication systems. In the scheme, a group of users can generate a common secret key over the public channel to hold a secure conference.