?CAREER: Secure Communication via Source and Channel Randomness? Current cryptosystem design depends on two main kinds of algorithms: secret-key and public-key algorithms. Secret-key algorithms are simple and efficient but have key management difficulty. Public-key algorithms are simple in key management but are computationally costly and vulnerable to the man-in-the-middle attack. This research investigates the emerging physical layer security approaches, which either achieve secure communication without keys, or simplify key management by generating keys using powerful coding techniques. This research aims at facilitating implementation of the physical layer security approaches to practical wireless communication systems, and stimulating interdisciplinary collaborations among researchers in mathematics, computer science and electrical engineering. This research provides a comprehensive framework to solve the problems of keyless secure communication and key agreement (key generation and distribution) for a variety of communication environments including noncoherent communication, channels with compound states, fading channels, noisy eavesdropping, and multihop networks. To be specific, this research investigates robust secure communication under channel uncertainty and delay constraint, fundamental tradeoff in multi-key agreement for different terminal pairs, key agreement algorithms by jointly using source and channel randomness, and key agreement protocols in multihop networks by exploiting network coding. This program is strongly coupled with educational and curriculum development at the University of Hawaii, and involves development of an advanced monograph on the topic of physical layer security to help disseminate the progresses in this active area in and outside the communication society.
