The objective of this research is to build new measurement-based methods for secure secret key establishment between two wireless devices, without ever communicating the secret key, using diverse physical characteristics of the wireless medium, notably an innovative measurement called temporal link signatures, and using device mobility. The intellectual merits of this research include (i) collection of extensive measurements and characterization of spatial and temporal behavior of wireless link signatures in a variety of indoor and outdoor settings, (ii) determination of the shared secret space in different settings through the use of analytical methods and the measurement data, (iii) novel methods for enhancing the length of the shared secrets to make them robust against brute force attacks, (iv) novel methods for dealing with asymmetric measurements of link signatures, and (v) a complete, implementable methodology, with specific configuration recommendations, for secure secret key establishment in real scenarios. This research will have a significant broad impacts. It generates a large amount of measurement data useful for various future wireless communications and security research; this data is and will continue to be available to the research community through the NSF-funded CRAWDAD repository. The results of this research potentially make mobile applications safer to use in ways that require far less complex management and far less computation than the existing cryptographic methods; these results benefit both security and goals of using mobility in green applications. Finally in broader impacts, this research will be used in conjunction with the PI's existing NSF STEP project for creating learning modules for high school students to demonstrate the problems and limitations of public key cryptosystems and the need for new ideas for secret key establishment.
CT-ISG: Opportunistic Secret Key Exchange Using Wireless Link Characteristics and Device Mobility