Holloway – University of London Egham , Surrey TW 20

We present a practical interactive conference key distribution system based on public keys, which is ‘proven’ secure provided the Diffie-Hellman problem is intractable. The system authenticates the users and allows them to compute their own conference key. A certain number of interactions is required, but the number of rounds is independent of the number of conference users. All users involved perform the same amount of computation and communication. Our technique for authentication can be extended and used as the basis for an authentication scheme which is ‘proven’ secure against any type of attack, provided the discrete logarithm problem is intractable. ********************** COVER PAGE ********************** ∗Research partly carried out while visiting the University of Wisconsin – Milwaukee. A Secure and Efficient Conference Key Distribution System (Extended Abstract) Abstract We present a practical interactive conference key distribution system based on public keys, which is ‘proven’ secure provided the Diffie-Hellman problem is intractable. The system authenticates the users and allows them to compute their own conference key. A certain number of interactions is required, but the number of rounds is independent of the number of conference users. All users involved perform the same amount of computation and communication. Our technique for authentication can be extended and used as the basis for an authentication scheme which is ‘proven’ secure against any type of attack, provided the discrete logarithm problem is intractable.