Wiretap Secret Key Capacity of Tree-PIN
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Secret key agreement (SKA) is an essential primitive in cryptography and information security. In a multiterminal key agreement problem, there are a set of terminals each having access to a component of vector random variable. The goal of the terminals is to establish a shared key among a designated subset of terminals. This problem has been studied under different assumptions about the adversary's information, the most general case corresponding to the setting where adversary's information is represented by a random variable that is correlated with all terminals' variables. Secret key capacity for this general adversary that is known as the wiretap adversary, is not known in the general case. In this paper, we calculate the wiretap secret key capacity of a Tree-PIN, and present a protocol that achieves this capacity for SKA among an arbitrary subset of terminals. We relate our work with known results and discuss future directions for research.
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