Abstract: A server with processor(s) and memory receives a transaction request from a first device to perform a transaction with an account and determines a security level for the transaction. When the security level satisfies predetermined criterion, the server: instructs the first device to suspend the transaction and to display a first interface indicating the suspended transaction; and sends a confirmation request, to a second device associated with the account, for voice verification of the transaction. The server receives voice verification information from the second device that includes audio data provided by a user of the second device and determines whether the voice verification information matches stored account verification data corresponding to the account. When there is a match, the server: processes the transaction; and instructs the first device to complete the transaction and to replace display of the first interface with a second interface indicating the completed transaction.