A system and method for online payment are described. The method includes receiving, from a vendor server, a payment amount, an identifier of a user and an identifier of a vendor; sending an indication of a payment to a user device associated with the identifier of the user; receiving, from the user device, a confirmation of the payment; receiving, from the user device, supplementary information generated when or after the user confirms the payment; determining legitimacy of the transaction based on the supplementary information; and making the payment from a financial account associated with the user identifier to a financial account associated with the identifier of the vendor if the transaction is legitimate.