简介:AllwatermarksaresharedintoshadowimagesusingVCS(VisualCryptographyScheme).Onlyonespecificshadow(asanewwatermark)isembeddedintothehostsignalandtheotheronesaredistributedtoeveryuserineachgroupasakey.Inthewatermarkingextractionprocedure,usersindifferentgroupcanobtaindifferentwatermarkbycombiningtheirshadowswiththeextractedonefromthewatermarkedsignal.Analysisandexperimentalresultsshowthatthenewwatermarkingmethodisnovel,secureandrobust.