After reading through the paper[1] it appears that the only security afforded is an ability to detect energy fluctuations caused by a MITM attacker? A public channel is then assumed to exist to allow both parties to broadcast the monitored energy levels to each other for comparison (evidently over a high bandwidth link and with low latency). A further assumption appears to be made that an attacker is unable to perform a MITM attack on the public broadcast link.
I am naturally sceptical of research of this nature that does not mention:
* practical implementation issues such as the required accuracy of clock synchronisation, required A2D converter parameters, required tolerances for electronic components, etc.
* emanation security/side channel considerations (timing analysis, power analysis and filtering, etc)
* prior work and existing equipment in the space of protected cabling: pressurised cable monitoring, time-domain reflectometry, etc.