  Alice and Bob want to share a secret key and to communicate an independent
message, both of which they desire to be kept secret from an eavesdropper Eve.
We study this problem of secret communication and secret key generation when
two resources are available -- correlated sources at Alice, Bob, and Eve, and a
noisy broadcast channel from Alice to Bob and Eve which is independent of the
sources. We are interested in characterizing the fundamental trade-off between
the rates of the secret message and secret key. We present an achievable
solution and prove its optimality for the parallel channels and sources case
when each sub-channel and source component satisfies a degradation order
(either in favor of the legitimate receiver or the eavesdropper). This includes
the case of jointly Gaussian sources and an additive Gaussian channel, for
which the secrecy region is evaluated.
