A Digital Multi-signature Scheme Based on ElGamal

Based on digital signature scheme,a new sequential digital multi-signature and a new broadcasting digital multi-signature based on DLP are proposed.The advantages of the proposed schemes are as follows : the multi-signature is a co-signature which is generated by multiple signers in collaborative and simultaneous manner,in which per signer generates partly signature.The length of the partly signatures does not grow with the number of the signers.The computation complicacy of the partly signature algorithm and the verification algorithm is independent of the signer′s number,and the new initial stage of the schemes is simple and the signatures of the schemes are random,and it needn’t to find inversion at the stage of signature or the stage of verification.The schemes are highly practical and secure.