1. A method for authenticating a user for a transaction, comprising: providing, by a device, a word string that comprises a random element; transmitting an audio segment, to a server computer, wherein the audio segment originated from the user; authenticating the user for the transaction based at least in part on a response, from the server computer, to the transmitted audio segment; and receiving, from the server computer, an indication that the user is authenticated for the transaction, wherein the indication is received after a delay in updating the fraud model for the user is updated with the audio segment upon the audio segment being held in a queue for a predetermined period of time, and when no fraud has been reported for the predetermined period of time.