Princeton University

School of Engineering & Applied Science

Layered Secrecy on Broadcast Networks

Shlomo Shamai (Shitz), Technion--Israel Institute of Technology
E-Quad, B205
Monday, February 8, 2016 - 3:00pm to 4:00pm

We review the setting of layered secrecy, addressing the degraded broadcast channel. The basic framework facilitates for a legitimate receiver who enjoys a better channel quality (channel state information, unavailable to the transmitter) to decode more secret messages, while the eavesdroppers with worse channel quality are kept ignorant of more messages. While this layered based secrecy coding approach (variable-to-fixed rate secrecy coding) is evaluated for degraded channels, the strategy is relevant to general settings, though not necessarily optimal. Examples of the approach for fading channels, where the legitimate and eavesdropping channels are corrupted by multiplicative random fading gains are presented.
We use a similar paradigm of a layered approach to address secret sharing problem, where groups of users are able to determine certain secrets by sharing their channel outputs, and other groups of users are kept ignorant of certain secrets even if they share their outputs.
In the concluding outlook, we discuss secret communication designs for different models.We also present secret capacity region results for the novel paradigm, of secrecy outside of a bounded range, focusing on simple models, for which it is shown that the secret capacity requires combinations of superposition coding, binning, and embedded codes, as well as sharing designs (as rate splitting).
(The talk is based on joint studies with S. Zou, Y. Liang, L. Lai and H.V. Poor)