  In this paper, inner and outer bounds on the capacity region of two-user
interference channels with two confidential messages have been proposed. By
adding secure multiplex coding to the error correction method in [15] which
achieves the best achievable capacity region for interference channel up to
now, we have shown that the improved secure capacity region compared with [2]
now is the whole Han-Kobayashi region. In addition, this construction not only
removes the rate loss incurred by adding dummy messages to achieve security,
but also change the original weak security condition in [2] to strong security.
Then the equivocation rate for a collection of secret messages has also been
evaluated, when the length of the message is finite or the information rate is
high, our result provides a good approximation for bounding the worst case
equivocation rate. Our results can be readily extended to the Gaussian
interference channel with little efforts.
