Abstract or Summary:
We present a deniable, anonymous group authentication (DAGA) protocol that provides anonymity, proportionality, deniability and forward anonymity. The anonymity property allows a user to authenticate as some group member without revealing exactly which one. Proportionality ensures that a client can authenticate only once as a unique group member per round. Deniability makes it possible to deny ever participating in a protocol. Finally, forward anonymity offers protection in case of a compromise of user’s private key after the protocol’s completion.