Asynchronous Group Authentication

Group authentication usually checks whether an individual user belongs to a pre-defined group each time but cannot authenticate all users at once without public key system. The paper proposes a Randomized component-based asynchronous (t,m,n) group authentication ((t,m,n)-RCAGA) scheme. In the scheme, each user employs the share of (t,n)-threshold secret sharing as the token, constructs a Randomized component (RC) with the share and verifies whether all users belong to a pre-defined group at once without requiring all users to release randomized components simultaneously. The proposed scheme is simple and flexible because each group member just uses a single share as the token and the scheme does not depend on any public key system. Analyses show the proposed scheme can resist up to t-1 group members conspiring to forge a token, and an adversary is unable to forge a valid token or derive a token from a RC.