For　the　first　time　we　investigate　cryptographic　applications　of　unambiguous　set　discrimination　in　quantum　oblivious　transfer.　In　particular,　using　techniques　for　unambiguous　set　discrimination,　we　present　a　novel　quantum　protocol　for　all-or-nothing　oblivious　transfer　(01).　Using　the　same　technique,　we　further　propose　an　efficient　and　economical　quantum　protocol　for　one-out-of-two　OT.　The　receiver　performs　only　Bell-state　measurements　(BSM)　to　attain　the　goal　of　all-or-nothing　OT　or　one-out-of-two　OT.　Moreover　in　the　second　protocol,　all　the　conclusive　and　inconclusive　results　are　useful　to　determine　the　sender＇s　secret　bits　so　that　the　qubit　efficiency　of　the　protocol　is　improved　to　100%.　Decoy-state-technology-like　detection　method　ensures　the　security　of　the　proposed　protocols.　(C)　2015　Elsevier　GmbH.　All　rights　reserved.