Highly　flexible　and　stable　plasmonic　nanopaper　comprised　of　silver　nanocubes　and　cellulose　nanofibres　was　fabricated　through　a　self-assembly-assisted　vacuum　filtration　method.　It　shows　significant　enhancement　of　the　fluorescence　emission　with　an　enhancement　factor　of　3.6　and　Raman　scattering　with　an　enhancement　factor　of　∼104,　excellent　mechanical　properties　with　tensile　strength　of　62.9　MPa　and　Young＇s　modulus　of　690.9　±　40　MPa,　and　a　random　distribution　of　Raman　intensity　across　the　whole　nanopaper.　The　plasmonic　nanopapers　were　encoded　with　multiplexed　optical　signals　including　surface　plasmon　resonance,　fluorescence　and　SERS　for　anti-counterfeiting　applications,　thus　increasing　security　levels.　The　surface　plasmon　resonance　and　fluorescence　information　is　used　as　the　first　layer　of　security　and　can　be　easily　verified　by　the　naked　eye,　while　the　unclonable　SERS　mapping　is　used　as　the　second　layer　of　security　and　can　be　readily　authenticated　by　Raman　spectroscopy　using　a　computer　vision　technique.　©　2020　The　Royal　Society　of　Chemistry.