Secure and efficient group blind signature scheme

Group blind signature is a special signature combined group signature and blind signature,which meets all advantages of both group and blind signature.Group blind signature is a useful basic tool in design of E-cash system.The paper proposes a secure and efficient group blind signature based on a group signature which is not coalition-resistant by adding random number to the secret key and introducing blind signature of knowledge.The scheme is coalition-resistant and can meet all security re-quirements of group blind signature.