In　the　process　of　outsourcing　the　production　of　micro-electrode-dot-array(MEDA)　biochips,　the　unprotected　IP(intellectual　property)　of　the　chip　design　is　vulnerable　to　theft　or　overproduction　attacks.　This　paper　proposes　a　logic　encryption-based　IP　protection　scheme　for　micro-electrode-dot-array　biochips,　called　MEDAguard,　which　uses　waste　droplets　and　input　droplets　from　bioassay　to　form　logic　encryption　modules　to　lock　the　bioassay,　thereby　protecting　it　from　theft　during　the　outsourcing　process.　In　addition,　a　security　evaluation　metric　is　proposed　to　assess　whether　the　generated　biochemical　reagents　meet　the　concentration　criteria　for　compliance　against　the　brute-force　attack　method　most　commonly　used　to　break　the　key.　Finally,　several　simulations　are　used　to　simulate　a　brute-force　attack　on　MEDAguard,　and　the　results　show　that　MEDAguard　can　effectively　resist　brute-force　attacks.　©　2022,　Chinese　Institute　of　Electronics.　All　right　reserved.