Digital multisignature with distinguished signing authorities

The digital multisignature is signed by group members with knowledge of multiple private keys. Two ElGamal-type efficient multisignature schemes that can combine all individual signatures into a multisignature without any data expansion have previously been proposed. However, since in these two schemes all group members sign the same message, these schemes are called multisignature schemes with undistinguished signing authorities. The authors now modify these schemes and convert them to a multisignature scheme with distinguished signing authorities. Each group member is responsible for preparing and signing a partial group message