Natural Web Interfaces

W e’re venturing into the era of the Internet of Things (IoT). As computing devices become smaller, smarter, and ubiquitous, computing has begun to embed into our environments by attaching to physical objects or things. IoT is bringing computing both onto our bodies and into our daily surroundings. Examples of onbody computing devices include human activity trackers, smart watches, and semi-permanent insulin pumps. Examples of in-environment computing devices include intelligent thermostats, smart appliances, remotely controllable household equipment, and weather-based automated lawn irrigation systems. Although IoT devices often have compute power close to those of conventional computing devices from a few years ago, one of the ways in which typical IoT devices differ is that they lack conventional user interfaces in the form of keyboards, mice, and touchscreens. Examples of such computing devices include the Fitbit activity tracker, sewable computing devices such as the Arduino Lilypad, and smart fabrics. A motivation for eliminating such user interfaces isn’t so much to reduce the cost as that the conventional interfaces often aren’t appropriate for the intended applications. For example, a smart fabric can have embedded antennas and communicate information about the person wearing the fabric to devices such as smartphones, but it wouldn’t quite make sense to attach a touchscreen to a shirt or a keypad to a Fitbit. This lack of a user interface gives rise to a fundamentally challenging question: How do we authenticate and authorize users for the IoT, where we lack conventional user interfaces? For example, one of the latest features of the Apple Watch is that if a user owns a (sufficiently new version of) Macbook Pro, an iPhone, and an Apple Watch, the user can set up the Macbook Pro to automatically unlock without entering a password. More specifically, as soon as the user opens the lid of her Macbook Pro, the laptop automatically unlocks if the following four conditions are satisfied: