Inthispaper,weproposeanewlightweight64-bitblockcipher,whichwecallMIBS,suitableforresource-constraineddevices,suchaslow-costRFIDtags.Wealsostudyitshardwareimplementationef-ficiency,aswellasitssecurity.ThehardwareimplementationofMIBSrequires1400gateson