The Sender-Excited Secret Key Agreement Model: Capacity Theorems
The authors consider the fundamental limits of the secret key generation problem when the sources are excited by the sender. In many practical communication settings, the channel may be influenced by the parties involved. Similar to recent works on probing capacity and channels with action-dependent states, their system model captures such a scenario. They derive single-letter expressions for the secret key capacity. Their coding strategy involves wiretap channel coding and a key generation scheme. By assuming that the eavesdropper receives a degraded version of the legitimate receiver's observation, they also obtain a capacity result that does not involve any auxiliary random variables.