Most people think of IoT devices in terms of their digital outputs, but these devices also output a wide variety of analog signals—noise, heat, EM radiation, power fluctuations. These are typically waste at best and security vulnerabilities at worst, but the DARPA LADS program asked the question: Can we use these to enhance the security of the device? Red Balloon Security was able to definitively answer yes, using an Optical AESOP. Instead of transmitting Symbiote telemetry through network packets, as is standard, Symbiotes configured to work with Optical AESOP blink a LED on a device’s case. An air-gapped system with a photodiode received and decoded these messages, allowing for a fully segregated AESOP system that could not be disabled by outside attackers. Red Balloon Security demonstrated the potential of this device with the “cyber smoke detector”, an air-gapped optical AESOP simultaneously monitoring a half-dozen devices of interest to the US military, sounding an alarm off any were hacked.