AttackingtheDeFiEcosystemwithFlashLoansforFunandProfitKaihuaQin,LiyiZhou,BenjaminLivshits,andArthurGervaisImperialCollegeLondon,UnitedKingdom{kaihua.qin,liyi.zhou,b.livshits,a.gervais}@imperial.ac.ukAbstract.Creditallowsalendertoloanoutsurpluscapitaltoabor-rower.Inthetraditionaleconomy,creditbearstheriskthatthebor-rowermaydefaultonitsdebt,thelenderhencerequiresupfrontcollat-eralfromtheborrower,plusinterestfeepayments.Duetotheatomicityofblockchaintransactions,lenderscanofferflashloans,i.e.,loansthatareonlyvalidwithinonetransactionandmustberepaidbytheendofthattransaction.Thisconcepthasleadtoanumberofinterestingattackpossibilities,someofwhichwereexploitedinF...