  In this paper, we investigate the secure rate-splitting for the two-user
multiple-input multiple-output (MIMO) broadcast channel with imperfect channel
state information at the transmitter (CSIT) and a multiple-antenna jammer,
where each receiver has an equal number of antennas and the jammer has perfect
channel state information (CSI). Specifically, we design a secure
rate-splitting multiple-access strategy, where the security of split private
and common messages is ensured by precoder design with joint nulling and
aligning the leakage information, regarding different antenna configurations.
Moreover, we show that the sum-secure degrees-of-freedom (SDoF) achieved by
secure rate-splitting is optimal and outperforms that by conventional
zero-forcing. Therefore, we reveal the sum-SDoF of the two-user MIMO broadcast
channel with imperfect CSIT and a jammer, and validate the superiority of
rate-splitting for the security purpose in this scenario with emphasis of MIMO.
