Secret Key Agreement: General Capacity and Second-Order Asymptotics

Masahito Hayashi; Himanshu Tyagi; Shun Watanabe

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arXiv · 1411.0735

Secret Key Agreement: General Capacity and Second-Order Asymptotics

Masahito Hayashi·Himanshu Tyagi·Shun Watanabe

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Abstract

We revisit the problem of secret key agreement using interactive public communication for two parties and propose a new secret key agreement protocol. The protocol attains the secret key capacity for general observations and attains the second-order asymptotic term in the maximum length of a secret key for independent and identically distributed observations. In contrast to the previously suggested secret key agreement protocols, the proposed protocol uses interactive communication. In fact, the standard one-way communication protocol used prior to this work fails to attain the asymptotic results above. Our converse proofs rely on a recently established upper bound for secret key lengths. Both our lower and upper bounds are derived in a single-shot setup and the asymptotic results are obtained as corollaries.

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Masahito Hayashi, Himanshu Tyagi, Shun Watanabe. 2014-11-03. Secret Key Agreement: General Capacity and Second-Order Asymptotics. https://arxiv.org/abs/1411.0735

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