DARPA is putting $36m to fund the Leveraging the Analog Domain for Security (LADS) Program (PDF). The agency is looking for proposals for "enhanced cyber defense through analysis of involuntary analog emissions," including things like "electromagnetic emissions, acoustic emanations, power fluctuations and thermal output variations." At the root of the program is frustration and a lack of confidence in digital monitoring and protection technologies developed for general purpose computing devices like desktops, laptops and servers.
The information security community's focus on "defense in-depth" approaches to cyber defense are ill suited for embedded systems because of cost, complexity or resource limitations. Even if that were possible, DARPA notes that "attackers have repeatedly demonstrated the ability to pierce protection boundaries, exploiting the fact that any security logic ultimately executes within the same computing unit as the rest of the (compromised) device software and the attacker's code."