As a more trackable performance metric for secrecy capacity, the secure degrees of freedom (SDoF) are widely studied for most multiuser networks in the high signal to noise ratio (SNR) region. However, the SDoF for these networks under rank-deficiency and arbitrary antenna configurations have not yet been determined. In this paper, the SDoF of two-user general multiple-input multiple-output ( MIMO ) interference channel with confidential messages (ICCM) under rank-deficiency are derived. For the two-user rank-deficient MIMO ICCM, the model is generalized to fully asymmetric settings, where the transmitters and receivers are equipped with arbitrary antennas. The outer bound of SDoF is the union of three outer bounds that are based on the Fano's inequality and the secrecy constraints, the secrecy penalty lemma and the role of a helper lemma, and the transmitters cooperation, respectively. The SDoF region is subdivided into five regions according to the number of transceivers antennas, and each region has an achievability scheme with designed null space transmission and alignment techniques. Numerical results indicate that the SDoF increase at first and then decrease as the rank of the channel matrix decreases. The SDoF improve by increasing the transmitting antenna or reducing receiving antenna, but the effect of the transmitting antenna is greater.
%U https://jcupt.bupt.edu.cn/EN/10.19682/j.cnki.1005-8885.2022.1026