  In this paper, intelligent reflecting surface (IRS) is proposed to enhance
the physical layer security in the Rician fading channel where the angular
direction of the eavesdropper is aligned with a legitimate user. In this
scenario, we consider a two-phase communication system under the active attacks
and passive eavesdropping. Particularly, in the first phase, the base station
avoids direct transmission to the attacked user. While, in the second phase,
other users cooperate to forward signals to the attacked user with the help of
IRS and energy harvesting technology. Under the active attacks, we investigate
an outage constrained beamforming design problem under the statistical cascaded
channel error model, which is solved by using the Bernstein-type inequality. As
for the passive eavesdropping, an average secrecy rate maximization problem is
formulated, which is addressed by a low complexity algorithm. Numerical results
show that the negative effect of the eavesdropper's channel error is greater
than that of the legitimate user.
