1. A method comprising: receiving, at a computer comprising a processor, a request from a requestor, the request for a challenge question and a response comprising an answer to the challenge question, wherein the challenge question and the response are used to authenticate a user device; accessing, by the computer, event data corresponding to an event associated with the user device; generating, by the computer, the challenge question based upon the event data; generating, by the computer, the response based upon the event data, the response comprising a valid response to the challenge question; and providing, by the computer, the challenge question and the response to the requestor.