Multiterminal secrecy generation

In this survey presentation, we consider Shannon-theoretic secret key generation by multiple parties for two categories of models. In the first category, termed source models, multiple terminals are provided prior and privileged access to correlated signals. In the second category, called channel models, these terminals are connected by a secure noisy channel with multiple input and outputs. In both categories, a public noiseless channel of unlimited capacity is available additionally for accomplishing the goal of secrecy generation. The secret key is generated for a subset of the terminals, with the cooperation of remaining terminals (if any) through their public communication. We ask for single-letter characterizations of secrecy capacities for these models when secrecy is required from an eavesdropper that observes only the public communication and perhaps also a set of terminals disjoint from the secrecy seeking set. Complete results have been obtained for secret key capacity for the source model and the channel model with a single input, while partial results are available for the channel model with multiple inputs. These will be surveyed, and some open problems will be discussed.