Full keyboards are difficult to implement on small mobile devices, and are sometimes replaced by keypads, with multiple characters assigned to each key. The Multitap method is often used for text entry on devices with keypads. While conceptually simple, Multitap requires one or more key presses to enter each desired letter, and is relatively inefficient from the standpoint of the number of keystrokes required to enter each word. It also requires a significant amount of visual searching to find a needed letter on a key.

    This talk presents our research on an enhanced Multitap method that uses predictive next-letter highlighting to aid visual searching and dynamic letter sequence re-ordering. Testing shows that this method, when compared to LetterWise, offers increased entry speeds, fewer errors, and greater novice user satisfaction.

    Protecting the privacy of sensitive information is an important consideration in the design of mobile devices and applications. As computing becomes more pervasive, users are able to access information in places such as airports, stores, and restaurants. When personal information is accessed in such public places, it needs to be shielded from strangers. Techniques are needed for the mobile environment to ensure that sensitive information is kept safe, yet still easily accessible and readily understandable in a variety of contexts. In addition, the user should not be required to actively protect sensitive data, but should feel secure in the fact that the application will automatically protect the data.

    To this end, we have been developing ways to display sensitive information on mobile devices such that it is not readily identifiable to an outside observer.\uffff We discuss our work to date, our ongoing investigations, and call for more research into this important aspect of ubiquitous computing.