User interface toolkit mechanisms for securing interface elements

User interface toolkit research has traditionally assumed that developers have full control of an interface. This assumption is challenged by the mashup nature of many modern interfaces, in which different portions of a single interface are implemented by multiple, potentially mutually distrusting developers (e.g., an Android application embedding a third-party advertisement). We propose considering security as a primary goal for user interface toolkits. We motivate the need for security at this level by examining today's mashup scenarios, in which security and interface flexibility are not simultaneously achieved. We describe a security-aware user interface toolkit architecture that secures interface elements while providing developers with the flexibility and expressivity traditionally desired in a user interface toolkit. By challenging trust assumptions inherent in existing approaches, this architecture effectively addresses important interface-level security concerns.