anonymous authentication with subset queries (extended abstract)
We develop new schemes for anonymous authentication that support identity escrow. Our protocols also allow a prover to demonstrate membership in an arbitrary subset of users; key revocation is an important special case of this feature. Using the Fiat-Shamir heuristic, our interactive authentication protocols yield new constructions for non-interactive group signature schemes. We use the higher-residuosity assumption, which leads to greater efficiency and more natural security proofs than previous constructions. It also leads to an increased vulnerability to collusion attacks, although countermeasures are available.
anonymous authentication identity escrow group signature