Internet　of　Medical　Things　(IoMT)　has　great　potential　in　delivering　medical　services.　In　IoMT,　data　users　(e.g.,　doctors)　may　want　to　process　data　collected　by　sensors　attached　to　data　owners’　body　(e.g.,　patients).　As　sensors　lack　computing　resources,　confidential　outsourcing　the　data　to　a　server　becomes　necessary　due　to　its　sensitivity.　Using　homomorphic　encryption　raises　limitations　in　secure　processing.　First,　as　decrypting　the　processed　result　requires　the　data　owners’　secret　key,　they　must　be　online　or　share　it　with　data　users.　Second,　when　processing　is　performed　on　the　data　of　multiple　data　owners,　the　interaction　becomes　harder.　Finally,　if　the　processed　result　is　sensitive,　it　lacks　confidentiality　as　data　owners　may　access　it.　In　this　paper,　we　propose　a　non-interactive　homomorphic　multi-party　computation　(HMPC)　protocol,　addressing　the　limitations　efficiently.　In　HMPC,　data　owners　encrypt　their　data　with　their　own　key　and　store　it　in　a　cloud　server.　Then,　data　users　select　the　required　data　from　the　cloud　server　and　outsource　their　own　encrypted　data　to　the　server　for　processing.　Afterwards,　they　decrypt　the　result　regardless　of　the　circuit　computed　and　without　interaction　with　the　data　owners.　Our　security　and　performance　analyses　demonstrate　that　HMPC　is　provably　secure　and　applicable.　©　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature　2024.