When　connecting　to　the　wireless　network　in　public　places,　users＇　personal　information　will　be　exposed　in　the　public　network,　which　is　easy　to　be　stolen　and　tampered　with　by　third　parties.　In　this　paper,　the　author　proposes　a　method　to　protect　user　information　when　connecting　to　public　wireless　networks　in　order　to　protect　users＇　privacy.　Random　linear　network　coding　is　used　to　encrypt　the　accessed　user　serial　number,　which　is　then　forwarded　to　the　upper　layer.　When　transmitted　to　a　specific　node,　the　encrypted　information　is　transmitted　to　the　server　for　information　decryption.　After　decoding　the　user　serial　number,　the　node　is　accessed.　In　this　way,　we　can　encrypt　user　information,　reduce　the　delay　time　of　forwarding,　and　improve　the　transmission　efficiency.　The　time　complexity　is　O(n2).　©　2019　IOP　Publishing　Ltd.　All　rights　reserved.