ID-based group signature

The authors present an ID-based group signature which is based on ordinary ID-based signature schemes such as Ohta-Okamoto´s scheme and Guillou-Quisquater´s scheme. Thus, the group signature is verified from the identities of group members. A signer proves that, by verifiable encryption of his ordinary signature, a group authority can identify him and, by Schoenmaker´s method, he proves that he knows a signature of a group member