  We consider a two-relay network in which a source aims to communicate a
confidential message to a destination while keeping the message secret from the
relay nodes. In the first hop, the channels from the source to the relays are
assumed to be block-fading and the channel states change arbitrarily -possibly
non-stationary and non-ergodic- across blocks. When the relay feedback on the
states of the source-to-relay channels is available on the source with no
delay, we provide an encoding strategy to achieve the optimal delay. We next
consider the case in which there is one-block delayed relay feedback on the
states of the source-to-relay channels. We show that for a set of channel state
sequences, the optimal delay with one-block delayed feedback differs from the
optimal delay with no-delayed feedback at most one block.
