Nowadays,　Internet　of　things　(IoT)　become　more　and　more　popular.　At　the　same　time,　the　requirements　of　security　mechanism　for　multimedia　in　IoT　received　a　huge　concern.　Multimedia　data　is　easily　shared　by　devises,　applications　and　social　networks　set　by　IoT.　Therefore,　it　is　indispensable　to　guarantee　the　privacy　and　security　of　shared　multimedia　data.　In　this　paper,　we　address　the　secure　multimedia　data　sharing　problem　in　cloud　computing　by　designing　proxy　re-encryption　(PRE)　scheme.　Our　schemes　cope　with　the　issues　of　data　validity,　data　confidentiality　and　authentication　during　encrypted　multimedia　data　sharing.　Unlike　as　usually　done　in　the　literature,　we　present　a　CCA-secure　PRE　scheme　which　removes　pairings　firstly.　Then　we　design　a　refined　CCA-secure　PRE　scheme　called　publicly　verifiable　PRE　without　parings.　It　is　demonstrated　that　our　schemes　meet　not　only　the　security　and　high　efficiency　requirements　of　multimedia　data　sharing,　but　also　the　public　verifiability.　The　validity　of　ciphertext,　both　the　original　and　re-encrypted　ciphertext,　can　be　publicly　verified　which　brings　additional　efficiency　due　to　offloading　the　validity　check　of　ciphertexts　from　the　power-limited　clients　to　any　semi-honest　public　cloud.