Converse results for secrecy generation over channels

We revisit the problem of secret key agreement in channel models, where in addition to a noisy, albeit secure channel, the terminals have access to a noiseless public communication channel. We show a strong converse for the secret key capacity in the point-to-point model and give upper bounds for the general case. Underlying our proofs is a recently discovered single-shot converse for secret key rates in multiterminal source models.