Recent results have shown that structured codes can be used to construct goodchannel codes, source codes and physical layer network codes for Gaussianchannels. For Gaussian channels with secrecy constraints, however, efforts todate rely on random codes. In this work, we advocate that structured codes areuseful for providing secrecy, and show how to compute the secrecy rate whenstructured codes are used. In particular, we solve the problem of boundingequivocation rates with one important class of structured codes, i.e., nestedlattice codes. Having established this result, we next demonstrate the use ofstructured codes for secrecy in two-user Gaussian channels. In particular, withstructured codes, we prove that a positive secure degree of freedom isachievable for a large class of fully connected Gaussian channels as long asthe channel is not degraded. By way of this, for these channels, we establishthat structured codes outperform Gaussian random codes at high SNR. This classof channels include the two-user multiple access wiretap channel, the two-userinterference channel with confidential messages and the two-user interferencewiretap channel. A notable consequence of this result is that, unlike the casewith Gaussian random codes, using structured codes for both transmission andcooperative jamming, it is possible to achieve an arbitrary large secrecy rategiven enough power.
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