Swarm　robotics　realize　collaboration　through　information　interaction　among　robots.　One　of　the　key　aspects　of　stable　and　reliable　operation　of　swarm　robotics　is　protecting　the　privacy　and　content　of　the　interactive　data.　Blockchain　has　been　traditionally　applied　to　digital　currency　due　to　its　decentralization　and　high　security　features.　Since　robots　can　serve　as　a　node　in　blockchain,　and　both　swarm　robotics　and　blockchain　share　the　distributed　architecture,　there　is　great　potential　to　apply　blockchain　technology　to　ensure　the　security　of　interactive　data　in　swarm　robotics.　In　this　paper,　a　brief　review　of　the　current　studies　on　the　applying　blockchain　to　swarm　robotics　is　given.　In　addition,　a　blockchain　data　protection　method　is　employed　to　protect　the　data　integrity　and　privacy　of　swarm　robotics.　Finally,　a　simulation　using　the　swarm　robotics　simulator　and　the　Ethereum　blockchain　test　network　is　conducted.　Results　demonstrate　the　effectiveness　of　the　proposed　method.　©　2022,　The　Author(s),　under　exclusive　license　to　Springer　Nature　Singapore　Pte　Ltd.