ID-based structured multisignature schemes

The signing structure of a multisignature scheme specifies the signing order for all signers when signing messages, and any multisignature not obeying the specified signing order will be verified as invalid. In accordance with the different responsibilities of the participant signers, the signing structure of a multisignature scheme could be further classified as the following three types: serial, parallel and mixed, where the mixed structure is regarded as the mix of the serial and the parallel, Based on the well-known ID-based public key system, we will propose three ID-based structured multisignature schemes and each scheme respectively realizes the serial, parallel and mixed signing structures. In the proposed schemes, the length of a multisignature is fixed and the verification of a multisignature is efficient, regardless of the number of signers involved, Besides, any invalid partial multisignature can be effectively identified during the generation of the multisignature.