  This paper establishes inner bounds on the secrecy capacity regions for the
general 3-receiver broadcast channel with one common and one confidential
message sets. We consider two setups. The first is when the confidential
message is to be sent to two receivers and kept secret from the third receiver.
Achievability is established using indirect decoding, Wyner wiretap channel
coding, and the new idea of generating secrecy from a publicly available
superposition codebook. The inner bound is shown to be tight for a class of
reversely degraded broadcast channels and when both legitimate receivers are
less noisy than the third receiver. The second setup investigated in this paper
is when the confidential message is to be sent to one receiver and kept secret
from the other two receivers. Achievability in this case follows from Wyner
wiretap channel coding and indirect decoding. This inner bound is also shown to
be tight for several special cases.
