  Recent results on source-channel coding for secure transmission show that
separation holds in several cases under some less-noisy conditions. However, it
has also been proved through a simple counterexample that pure analog schemes
can be optimal and hence outperform digital ones. According to these
observations and assuming matched-bandwidth, we present a novel hybrid
digital/analog scheme that aims to gather the advantages of both digital and
analog ones. In the quadratic Gaussian setup when side information is only
present at the eavesdropper, this strategy is proved to be optimal.
Furthermore, it outperforms both digital and analog schemes and cannot be
achieved via time-sharing. An application example to binary symmetric sources
with side information is also investigated.
