On concurrent identification protocols (extended abstract)

Abstract

We consider communication networks in which it is not possible to identify the source of a message which is broadcasted through the network. A natural question is whether it is possible for two users to identify each other concurrently, through a secure two-party protocol. We show that more than the existence of a secure Public Key Cryptosystem should be assumed in order to present a secure protocol for concurrent identification. We present two concurrent identification protocols: The first one relies on the existence of a center who has distributed “identification tags” to the users; while the second protocol relies on the distribution of “experimental sequences” by instances of a pre-protocol which have taken place between every two users.