The emerging Internet of Things (IoT) has several salient characteristics that differentiate it from existing wireless networking architectures. These include the deployment of very large numbers of (possibly) low-complexity terminals; the need for low-latency, short-packet communications (e.g., to support automation); light or no infrastructure; and primary applications of data gathering, inference and control. These characteristics shape the issue of security in the IoT, and an important aspect of this issue is the need for new fundamental insights about security that address these characteristics. This talk discussed recent research advances along these lines.