  We study deterministic approximations of the Gaussian two-user multiple
access wiretap channel (G-MAC-WT) and the Gaussian wiretap channel with a
helper (G-WT-H). These approximations enable results beyond the recently shown
2/3 and 1/2 secure degrees of freedom (s.d.o.f.) for the G-MAC-WT and the
G-WT-H, respectively. While the s.d.o.f. were obtained by real interference
alignment, our approach uses signal-scale alignment. We show achievable schemes
which are independent of the rationality of the channel gains. Moreover, our
results can differentiate between channel strengths, in particular between both
users, and establishes secrecy rates dependent on this difference. We can show
that the resulting achievable secrecy rates tend to the s.d.o.f. for vanishing
channel gain differences. Moreover, we extend previous and develop new
techniques to prove general s.d.o.f. bounds for varying channel strengths and
show that our achievable schemes reach the bounds for certain channel gain
parameters. We believe that our analysis is the next step towards a
constant-gap analysis of the G-MAC-WT and the G-WT-H.
