Secure degrees of freedom of the interference channel with no eavesdropper CSI

We consider the K-user interference channel with an external eavesdropper, with no eavesdropper's channel state information at the transmitters (CSIT). We determine the exact sum secure degrees of freedom (s.d.o.f.) for this channel by providing a new alignment based achievable scheme and a matching converse. Our results show that the lack of eavesdropper's CSIT does not have a significant impact on the optimal s.d.o.f. of the interference channel with an external eavesdropper, especially when the number of users is large.