A Flash advertisement is provided, and access to sensitive data associated with the Flash advertisement is restricted. First library code is stored at a first security domain, the first library code to control playback of the Flash advertisement; and second library code is stored at a second security domain, the second library code to access the sensitive data. An application at a third security domain is permitted to access the first library code, and only code residing at the first security domain is permitted to access the second library code.