Authorized Group Signature

All the group signature schemes available are supposed that all members have the same right to sign and can not be used in the cases where different members have different rights.To cover this shortage,this paper introduces a concept of the authorized group signature and proposes an authorized group signature scheme to implement it.The authors add a new party,the right manager,and a new procedure,AUTHORIZE procedure to the standard group signatures to achieve the authorized group signatures.In the proposed authorized group signature scheme,the signer can sign a signature only when he knows both a secret key of one group member and a secret certificate so he can sign only in his own right authorized by the right manager,and the verifier can verify the signer's right by verifying the corresponding public certificate.