  We consider the symmetric Gaussian interference channel where two users try
to enhance their secrecy rates in a cooperative manner. Artificial noise is
introduced along with useful information. We derive the power control and
artificial noise parameter for two kinds of optimal points, max-min point and
single user point. It is shown that there exists a critical value $P_c$ of the
power constraint, below which the max-min point is an optimal point on the
secrecy rate region, and above which time-sharing between single user points
achieves larger secrecy rate pairs. It is also shown that artificial noise can
help to enlarge the secrecy rate region, in particular on the single user
point.
