COSI

We study communication problems where undetectability or location privacy is required. Such secrecy requirements are important, e.g., for “smart devices” which only communicate scarcely to send short messages, where much sensitive information is contained not in the messages, but in who is sending the message, when, and from where, etc. Recent works on “covert communication” provided a theoretical framework for analyzing undetectability. For a broad class of channels, the “square-root law” holds: the number of bits that can be communicated covertly is proportional to the square root of total communication time. This implies that the maximum bits per second for covert communication tends to zero as total communication time grows. In this project we explore new channel models and try to find scenarios where positive-rate covert communication is possible. We also further explore the square-root scenario to bridge the gap between theoretical results and real-life applications.