Abstract.Weputforwardnewtechniquesfordesigningsignatureschemes.Asaresult,wepresentpracticalsignatureschemesbasedontheCDH,theRSA,andtheSISassumptions.Ourschemescomparefavorablywithexistingschemesbasedontheseassumptions.Ourcoreideaistheuseoftag-basedsignatures.Concretely,eachsignatures