It was a wry comment about emanations security and TEMPEST (https://en.wikipedia.org/wiki/Tempest_%28codename%29 https://en.wikipedia.org/wiki/Tempest_%28codena

It was a wry comment about emanations security and TEMPEST (https://en.wikipedia.org/wiki/Tempest_%28codename%29 https://en.wikipedia.org/wiki/Tempest_%28codename%29), which people think about mainly for CRTs, with the implication I have no doubt there exist methods for remote differential power analysis of crypto operations as well. Helpfully in the mean time, someone has written a wiki page about some stuff we used to add to threat models: https://en.wikipedia.org/wiki/Radiofrequency_MASINT https://en.wikipedia.org/wiki/Radiofrequency_MASINT Just because you're paranoid doesn't mean they aren't actually using RF side channels to steal your keys and passphrases.