1. A method in a data processing system for trusted application event auditing, the method comprising: registering a callback function with an audit service, wherein the callback function is trusted code associated with a first callback function identifier; registering an event receiver, and associating the event receiver with the callback function; registering a second callback function identifier with the audit service; associating the second callback function identifier with the callback function; providing the second callback function identifier from a trusted application to the event receiver in response to seeking validation of the trusted application; receiving an event having the second callback function identifier at the event receiver, wherein the received event comprises an event identifier; calling the audit service with the second callback function identifier being included as an argument of the callback function; identifying the callback function based on matching the second callback function identifier to the first callback function identifier; calling the callback function to validate authenticity of the event, wherein the calling comprises calling the callback function using the event identifier; and removing the second callback function identifier from registration in the audit service in response to the second callback function identifier being included as the argument of the callback function.