medium10 pts · first answer countstoken-standardssmart-contract-security

Fee-on-transfer token deposits

A vault credits users with the amount argument after calling transferFrom(user, vault, amount). A token takes a 2% fee on every transfer. What goes wrong and how do you handle it?

A.Nothing; the fee is paid by the sender separatelyB.transferFrom reverts for fee tokens, so deposits always failC.The vault credits more than it received, so it becomes insolvent; measure the balance before and after the transfer and credit the differenceD.The vault receives more than expected; cap deposits at 98%

← Tokens that return nothing EIP-712 domain separator →