Simple-Yet-Efficient Construction and Revocation of Group Signatures

Group signatures are typically used to authenticate the signer of message while preserving the privacy of the signer. Group signature should be minimized to reduce potential communication overhead. We propose a novel short group signature scheme that generates constant-size group public key and constant-size group signature. The scheme, using pairing-friendly elliptic curves, is efficient in construction. We give the security proof under XDH and ECDL hardness assumptions in the BMW model. Furthermore, we propose two group membership revocation methods which provide revocation information only to verifiers. One revocation method exposes partial private key of revoked users, which requires less revocation information. The other revocation method includes mixed private key information without revealing the real private keys of revoked users. This method is simple in revocation check.