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.