  We consider the Gaussian wiretap channel with M helpers, where no
eavesdropper channel state information (CSI) is available at the legitimate
entities. The exact secure d.o.f. of the Gaussian wiretap channel with M
helpers with perfect CSI at the transmitters was found in [1], [2] to be
M/(M+1). One of the key ingredients of the optimal achievable scheme in [1],
[2] is to align cooperative jamming signals with the information symbols at the
eavesdropper to limit the information leakage rate. This required perfect
eavesdropper CSI at the transmitters. Motivated by the recent result in [3], we
propose a new achievable scheme in which cooperative jamming signals span the
entire space of the eavesdropper, but are not exactly aligned with the
information symbols. We show that this scheme achieves the same secure d.o.f.
of M/(M+1) in [1], [2] but does not require any eavesdropper CSI; the
transmitters blindly cooperative jam the eavesdropper.
